List<T>.Sort List<T>.Sort List<T>.Sort List<T>.Sort Method

定义

使用指定或默认的 IComparer<T> 实现或提供的 Comparison<T> 委托对 List<T> 中的元素或部分元素进行排序,以比较列表元素。Sorts the elements or a portion of the elements in the List<T> using either the specified or default IComparer<T> implementation or a provided Comparison<T> delegate to compare list elements.

重载

Sort(Comparison<T>) Sort(Comparison<T>) Sort(Comparison<T>) Sort(Comparison<T>)

使用指定的 Comparison<T>,对整个 List<T> 中的元素进行排序。Sorts the elements in the entire List<T> using the specified Comparison<T>.

Sort(Int32, Int32, IComparer<T>) Sort(Int32, Int32, IComparer<T>) Sort(Int32, Int32, IComparer<T>) Sort(Int32, Int32, IComparer<T>)

使用指定的比较器对 List<T> 中某个范围内的元素进行排序。Sorts the elements in a range of elements in List<T> using the specified comparer.

Sort() Sort() Sort() Sort()

使用默认比较器对整个 List<T> 中的元素进行排序。Sorts the elements in the entire List<T> using the default comparer.

Sort(IComparer<T>) Sort(IComparer<T>) Sort(IComparer<T>) Sort(IComparer<T>)

使用指定的比较器对整个 List<T> 中的元素进行排序。Sorts the elements in the entire List<T> using the specified comparer.

Sort(Comparison<T>) Sort(Comparison<T>) Sort(Comparison<T>) Sort(Comparison<T>)

使用指定的 Comparison<T>,对整个 List<T> 中的元素进行排序。Sorts the elements in the entire List<T> using the specified Comparison<T>.

public:
 void Sort(Comparison<T> ^ comparison);
public void Sort (Comparison<T> comparison);
member this.Sort : Comparison<'T> -> unit
Public Sub Sort (comparison As Comparison(Of T))

参数

comparison
Comparison<T> Comparison<T> Comparison<T> Comparison<T>

比较元素时要使用的 Comparison<T>The Comparison<T> to use when comparing elements.

异常

comparison 的实现导致排序时出现错误。The implementation of comparison caused an error during the sort. 例如,将某个项与其自身比较时,comparison 可能不返回 0。For example, comparison might not return 0 when comparing an item with itself.

示例

下面的代码演示简单Sort业务Sort对象上的和方法重载。The following code demonstrates the Sort and Sort method overloads on a simple business object. 调用方法会导致为部件类型使用默认比较器, Sort并使用匿名方法实现方法。 SortCalling the Sort method results in the use of the default comparer for the Part type, and the Sort method is implemented using an anonymous method.

using System;
using System.Collections.Generic;
// Simple business object. A PartId is used to identify the type of part 
// but the part name can change. 
public class Part : IEquatable<Part> , IComparable<Part>
{
    public string PartName { get; set; }

    public int PartId { get; set; }

    public override string ToString()
    {
        return "ID: " + PartId + "   Name: " + PartName;
    }
    public override bool Equals(object obj)
    {
        if (obj == null) return false;
        Part objAsPart = obj as Part;
        if (objAsPart == null) return false;
        else return Equals(objAsPart);
    }
    public int SortByNameAscending(string name1, string name2)
    {
        
        return name1.CompareTo(name2);
    }

    // Default comparer for Part type.
    public int CompareTo(Part comparePart)
    {
          // A null value means that this object is greater.
        if (comparePart == null)
            return 1;
            
        else
            return this.PartId.CompareTo(comparePart.PartId);
    }
    public override int GetHashCode()
    {
        return PartId;
    }
    public bool Equals(Part other)
    {
        if (other == null) return false;
        return (this.PartId.Equals(other.PartId));
    }
    // Should also override == and != operators.

}
public class Example
{
    public static void Main()
    {
        // Create a list of parts.
        List<Part> parts = new List<Part>();

        // Add parts to the list.
        parts.Add(new Part() { PartName = "regular seat", PartId = 1434 });
        parts.Add(new Part() { PartName= "crank arm", PartId = 1234 });
        parts.Add(new Part() { PartName = "shift lever", PartId = 1634 }); ;
        // Name intentionally left null.
        parts.Add(new Part() {  PartId = 1334 });
        parts.Add(new Part() { PartName = "banana seat", PartId = 1444 });
        parts.Add(new Part() { PartName = "cassette", PartId = 1534 });
       

        // Write out the parts in the list. This will call the overridden 
        // ToString method in the Part class.
        Console.WriteLine("\nBefore sort:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }


        // Call Sort on the list. This will use the 
        // default comparer, which is the Compare method 
        // implemented on Part.
        parts.Sort();


        Console.WriteLine("\nAfter sort by part number:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }
       
        // This shows calling the Sort(Comparison(T) overload using 
        // an anonymous method for the Comparison delegate. 
        // This method treats null as the lesser of two values.
        parts.Sort(delegate(Part x, Part y)
        {
            if (x.PartName == null && y.PartName == null) return 0;
            else if (x.PartName == null) return -1;
            else if (y.PartName == null) return 1;
            else return x.PartName.CompareTo(y.PartName);
        });

        Console.WriteLine("\nAfter sort by name:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }
       
        /*
       
            Before sort:
        ID: 1434   Name: regular seat
        ID: 1234   Name: crank arm
        ID: 1634   Name: shift lever
        ID: 1334   Name:
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette

        After sort by part number:
        ID: 1234   Name: crank arm
        ID: 1334   Name:
        ID: 1434   Name: regular seat
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette
        ID: 1634   Name: shift lever

        After sort by name:
        ID: 1334   Name:
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette
        ID: 1234   Name: crank arm
        ID: 1434   Name: regular seat
        ID: 1634   Name: shift lever

         */

    }
}
Imports System.Collections.Generic

' Simple business object. A PartId is used to identify the type of part 
' but the part name can change. 
Public Class Part
    Implements IEquatable(Of Part)
    Implements IComparable(Of Part)
    Public Property PartName() As String
        Get
            Return m_PartName
        End Get
        Set(value As String)
            m_PartName = Value
        End Set
    End Property
    Private m_PartName As String

    Public Property PartId() As Integer
        Get
            Return m_PartId
        End Get
        Set(value As Integer)
            m_PartId = Value
        End Set
    End Property
    Private m_PartId As Integer

    Public Overrides Function ToString() As String
        Return "ID: " & PartId & "   Name: " & PartName
    End Function

    Public Overrides Function Equals(obj As Object) As Boolean
        If obj Is Nothing Then
            Return False
        End If
        Dim objAsPart As Part = TryCast(obj, Part)
        If objAsPart Is Nothing Then
            Return False
        Else
            Return Equals(objAsPart)
        End If
    End Function

    Public Function SortByNameAscending(name1 As String, name2 As String) As Integer

        Return name1.CompareTo(name2)
    End Function

    ' Default comparer for Part.
    Public Function CompareTo(comparePart As Part) As Integer _
            Implements IComparable(Of ListSortVB.Part).CompareTo
        ' A null value means that this object is greater.
        If comparePart Is Nothing Then
            Return 1
        Else

            Return Me.PartId.CompareTo(comparePart.PartId)
        End If
    End Function
    Public Overrides Function GetHashCode() As Integer
        Return PartId
    End Function
    Public Overloads Function Equals(other As Part) As Boolean Implements IEquatable(Of ListSortVB.Part).Equals
        If other Is Nothing Then
            Return False
        End If
        Return (Me.PartId.Equals(other.PartId))
    End Function
    ' Should also override == and != operators.

End Class
Public Class Example
    Public Shared Sub Main()
        ' Create a list of parts.
        Dim parts As New List(Of Part)()

        ' Add parts to the list.
        parts.Add(New Part() With { _
             .PartName = "regular seat", _
             .PartId = 1434 _
        })
        parts.Add(New Part() With { _
             .PartName = "crank arm", _
             .PartId = 1234 _
        })
        parts.Add(New Part() With { _
             .PartName = "shift lever", _
             .PartId = 1634 _
        })


        ' Name intentionally left null.
        parts.Add(New Part() With { _
             .PartId = 1334 _
        })
        parts.Add(New Part() With { _
             .PartName = "banana seat", _
             .PartId = 1444 _
        })
        parts.Add(New Part() With { _
             .PartName = "cassette", _
             .PartId = 1534 _
        })


        ' Write out the parts in the list. This will call the overridden 
        ' ToString method in the Part class.
        Console.WriteLine(vbLf & "Before sort:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next


        ' Call Sort on the list. This will use the 
        ' default comparer, which is the Compare method 
        ' implemented on Part.
        parts.Sort()


        Console.WriteLine(vbLf & "After sort by part number:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next

        ' This shows calling the Sort(Comparison(T) overload using 
        ' an anonymous delegate method. 
        ' This method treats null as the lesser of two values.
        parts.Sort(Function(x As Part, y As Part)
                             If x.PartName Is Nothing AndAlso y.PartName Is Nothing Then
                                 Return 0
                             ElseIf x.PartName Is Nothing Then
                                 Return -1
                             ElseIf y.PartName Is Nothing Then
                                 Return 1
                             Else
                                 Return x.PartName.CompareTo(y.PartName)
                             End If
                         End Function)
        

        Console.WriteLine(vbLf & "After sort by name:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next

        '
        '        
        '            Before sort:
        '            ID: 1434   Name: regular seat
        '            ID: 1234   Name: crank arm
        '            ID: 1634   Name: shift lever
        '            ID: 1334   Name:
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '
        '            After sort by part number:
        '            ID: 1234   Name: crank arm
        '            ID: 1334   Name:
        '            ID: 1434   Name: regular seat
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '            ID: 1634   Name: shift lever
        '
        '            After sort by name:
        '            ID: 1334   Name:
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '            ID: 1234   Name: crank arm
        '            ID: 1434   Name: regular seat
        '            ID: 1634   Name: shift lever

    End Sub
End Class

下面的示例演示Sort(Comparison<T>)方法重载。The following example demonstrates the Sort(Comparison<T>) method overload.

该示例定义了一个名为CompareDinosByLength的字符串的替代比较方法。The example defines an alternative comparison method for strings, named CompareDinosByLength. 此方法的工作方式如下:首先, 对这些比较的值null进行测试, 并将空引用视为小于非空引用。This method works as follows: First, the comparands are tested for null, and a null reference is treated as less than a non-null. 其次, 比较字符串长度, 较长的字符串被认为更大。Second, the string lengths are compared, and the longer string is deemed to be greater. 第三, 如果长度相等, 则使用普通字符串比较。Third, if the lengths are equal, ordinary string comparison is used.

List<T>创建一个字符串, 并以无特定顺序填充四个字符串。A List<T> of strings is created and populated with four strings, in no particular order. 此列表还包括一个空字符串和一个空引用。The list also includes an empty string and a null reference. 显示列表, 使用Comparison<T> CompareDinosByLength表示方法的泛型委托进行排序, 并再次显示。The list is displayed, sorted using a Comparison<T> generic delegate representing the CompareDinosByLength method, and displayed again.

using namespace System;
using namespace System::Collections::Generic;

int CompareDinosByLength(String^ x, String^ y)
{
    if (x == nullptr)
    {
        if (y == nullptr)
        {
            // If x is null and y is null, they're
            // equal. 
            return 0;
        }
        else
        {
            // If x is null and y is not null, y
            // is greater. 
            return -1;
        }
    }
    else
    {
        // If x is not null...
        //
        if (y == nullptr)
            // ...and y is null, x is greater.
        {
            return 1;
        }
        else
        {
            // ...and y is not null, compare the 
            // lengths of the two strings.
            //
            int retval = x->Length.CompareTo(y->Length);

            if (retval != 0)
            {
                // If the strings are not of equal length,
                // the longer string is greater.
                //
                return retval;
            }
            else
            {
                // If the strings are of equal length,
                // sort them with ordinary string comparison.
                //
                return x->CompareTo(y);
            }
        }
    }
};

void Display(List<String^>^ list)
{
    Console::WriteLine();
    for each(String^ s in list)
    {
        if (s == nullptr)
            Console::WriteLine("(null)");
        else
            Console::WriteLine("\"{0}\"", s);
    }
};

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();
    dinosaurs->Add("Pachycephalosaurus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("");
    dinosaurs->Add(nullptr);
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Deinonychus");
    Display(dinosaurs);

    Console::WriteLine("\nSort with generic Comparison<String^> delegate:");
    dinosaurs->Sort(
        gcnew Comparison<String^>(CompareDinosByLength));
    Display(dinosaurs);

}

/* This code example produces the following output:

"Pachycephalosaurus"
"Amargasaurus"
""
(null)
"Mamenchisaurus"
"Deinonychus"

Sort with generic Comparison<String^> delegate:

(null)
""
"Deinonychus"
"Amargasaurus"
"Mamenchisaurus"
"Pachycephalosaurus"
 */
using System;
using System.Collections.Generic;

public class Example
{
    private static int CompareDinosByLength(string x, string y)
    {
        if (x == null)
        {
            if (y == null)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == null)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x.Length.CompareTo(y.Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x.CompareTo(y);
                }
            }
        }
    }

    public static void Main()
    {
        List<string> dinosaurs = new List<string>();
        dinosaurs.Add("Pachycephalosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("");
        dinosaurs.Add(null);
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");
        Display(dinosaurs);

        Console.WriteLine("\nSort with generic Comparison<string> delegate:");
        dinosaurs.Sort(CompareDinosByLength);
        Display(dinosaurs);

    }

    private static void Display(List<string> list)
    {
        Console.WriteLine();
        foreach( string s in list )
        {
            if (s == null)
                Console.WriteLine("(null)");
            else
                Console.WriteLine("\"{0}\"", s);
        }
    }
}

/* This code example produces the following output:

"Pachycephalosaurus"
"Amargasaurus"
""
(null)
"Mamenchisaurus"
"Deinonychus"

Sort with generic Comparison<string> delegate:

(null)
""
"Deinonychus"
"Amargasaurus"
"Mamenchisaurus"
"Pachycephalosaurus"
 */
Imports System.Collections.Generic

Public Class Example

    Private Shared Function CompareDinosByLength( _
        ByVal x As String, ByVal y As String) As Integer

        If x Is Nothing Then
            If y Is Nothing Then 
                ' If x is Nothing and y is Nothing, they're
                ' equal. 
                Return 0
            Else
                ' If x is Nothing and y is not Nothing, y
                ' is greater. 
                Return -1
            End If
        Else
            ' If x is not Nothing...
            '
            If y Is Nothing Then
                ' ...and y is Nothing, x is greater.
                Return 1
            Else
                ' ...and y is not Nothing, compare the 
                ' lengths of the two strings.
                '
                Dim retval As Integer = _
                    x.Length.CompareTo(y.Length)

                If retval <> 0 Then 
                    ' If the strings are not of equal length,
                    ' the longer string is greater.
                    '
                    Return retval
                Else
                    ' If the strings are of equal length,
                    ' sort them with ordinary string comparison.
                    '
                    Return x.CompareTo(y)
                End If
            End If
        End If

    End Function

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)
        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("")
        dinosaurs.Add(Nothing)
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Deinonychus")
        Display(dinosaurs)

        Console.WriteLine(vbLf & "Sort with generic Comparison(Of String) delegate:")
        dinosaurs.Sort(AddressOf CompareDinosByLength)
        Display(dinosaurs)

    End Sub

    Private Shared Sub Display(ByVal lis As List(Of String))
        Console.WriteLine()
        For Each s As String In lis
            If s Is Nothing Then
                Console.WriteLine("(Nothing)")
            Else
                Console.WriteLine("""{0}""", s)
            End If
        Next
    End Sub
End Class

' This code example produces the following output:
'
'"Pachycephalosaurus"
'"Amargasaurus"
'""
'(Nothing)
'"Mamenchisaurus"
'"Deinonychus"
'
'Sort with generic Comparison(Of String) delegate:
'
'(Nothing)
'""
'"Deinonychus"
'"Amargasaurus"
'"Mamenchisaurus"
'"Pachycephalosaurus"

注解

如果comparison提供了, 则使用委托表示List<T>的方法对的元素进行排序。If comparison is provided, the elements of the List<T> are sorted using the method represented by the delegate.

如果comparisonnull ,ArgumentNullException则引发。If comparison is null, an ArgumentNullException is thrown.

此方法使用Array.Sort, 它将应用反省排序, 如下所示:This method uses Array.Sort, which applies the introspective sort as follows:

  • 如果分区大小少于16个元素, 则使用插入排序算法If the partition size is fewer than 16 elements, it uses an insertion sort algorithm

  • 如果分区数超过2个 log n, 其中n是输入数组的范围, 则使用Heapsort算法。If the number of partitions exceeds 2 log n, where n is the range of the input array, it uses a Heapsort algorithm.

  • 否则, 它将使用快速排序算法。Otherwise, it uses a Quicksort algorithm.

此实现执行不稳定的排序;也就是说, 如果两个元素相等, 则可能不会保留它们的顺序。This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. 相反, 稳定排序会保留相等元素的顺序。In contrast, a stable sort preserves the order of elements that are equal.

平均而言, 此方法为 o (n log n) 操作, 其中n Count为; 在最坏情况下, 它是一个 o (n2) 操作。On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n2) operation.

另请参阅

Sort(Int32, Int32, IComparer<T>) Sort(Int32, Int32, IComparer<T>) Sort(Int32, Int32, IComparer<T>) Sort(Int32, Int32, IComparer<T>)

使用指定的比较器对 List<T> 中某个范围内的元素进行排序。Sorts the elements in a range of elements in List<T> using the specified comparer.

public:
 void Sort(int index, int count, System::Collections::Generic::IComparer<T> ^ comparer);
public void Sort (int index, int count, System.Collections.Generic.IComparer<T> comparer);
member this.Sort : int * int * System.Collections.Generic.IComparer<'T> -> unit
Public Sub Sort (index As Integer, count As Integer, comparer As IComparer(Of T))

参数

index
Int32 Int32 Int32 Int32

要排序范围的从零开始的起始索引。The zero-based starting index of the range to sort.

count
Int32 Int32 Int32 Int32

要排序的范围的长度。The length of the range to sort.

comparer
IComparer<T> IComparer<T> IComparer<T> IComparer<T>

比较元素时要使用的 IComparer<T> 实现,若要使用默认比较器 Default,则为 nullThe IComparer<T> implementation to use when comparing elements, or null to use the default comparer Default.

异常

index 小于 0。index is less than 0.

-or- count 小于 0。count is less than 0.

indexcount 未在 List<T> 中指定有效范围。index and count do not specify a valid range in the List<T>.

-or- comparer 的实现导致排序时出现错误。The implementation of comparer caused an error during the sort. 例如,将某个项与其自身比较时,comparer 可能不返回 0。For example, comparer might not return 0 when comparing an item with itself.

comparernull,且默认比较器 Default 找不到 IComparable<T> 泛型接口或类型为 TIComparable 接口的实现。comparer is null, and the default comparer Default cannot find implementation of the IComparable<T> generic interface or the IComparable interface for type T.

示例

下面的示例演示Sort(Int32, Int32, IComparer<T>)方法重载BinarySearch(Int32, Int32, T, IComparer<T>)和方法重载。The following example demonstrates the Sort(Int32, Int32, IComparer<T>) method overload and the BinarySearch(Int32, Int32, T, IComparer<T>) method overload.

该示例定义了一个名为 DinoCompare 的字符串的替代比较器IComparer<string> ,IComparer(Of String)该比较器IComparer<String^>实现了C++(在 Visual Basic 中的 Visual) 泛型接口。The example defines an alternative comparer for strings named DinoCompare, which implements the IComparer<string> (IComparer(Of String) in Visual Basic, IComparer<String^> in Visual C++) generic interface. 比较器的工作方式如下:首先, 对这些比较的值null进行测试, 并将空引用视为小于非空引用。The comparer works as follows: First, the comparands are tested for null, and a null reference is treated as less than a non-null. 其次, 比较字符串长度, 较长的字符串被认为更大。Second, the string lengths are compared, and the longer string is deemed to be greater. 第三, 如果长度相等, 则使用普通字符串比较。Third, if the lengths are equal, ordinary string comparison is used.

创建List<T>一个字符串, 并使用5个 herbivorous 恐龙和3个 carnivorous 恐龙的名称填充。A List<T> of strings is created and populated with the names of five herbivorous dinosaurs and three carnivorous dinosaurs. 这两个组中的每个组的名称不是任何特定的排序顺序。Within each of the two groups, the names are not in any particular sort order. 随即显示列表, 使用替代比较器对 herbivores 的范围进行排序, 并再次显示该列表。The list is displayed, the range of herbivores is sorted using the alternate comparer, and the list is displayed again.

然后BinarySearch(Int32, Int32, T, IComparer<T>) , 使用方法重载仅搜索 "Brachiosaurus" 的 herbivores 范围。The BinarySearch(Int32, Int32, T, IComparer<T>) method overload is then used to search only the range of herbivores for "Brachiosaurus". 找不到该字符串, C#并将该C++ Xor BinarySearch(Int32, Int32, T, IComparer<T>)方法返回的负数的按位求补 (在和视觉对象中为 ~ Visual Basic) 用作插入新字符串的索引。The string is not found, and the bitwise complement (the ~ operator in C# and Visual C++, Xor -1 in Visual Basic) of the negative number returned by the BinarySearch(Int32, Int32, T, IComparer<T>) method is used as an index for inserting the new string.

using namespace System;
using namespace System::Collections::Generic;

public ref class DinoComparer: IComparer<String^>
{
public:
    virtual int Compare(String^ x, String^ y)
    {
        if (x == nullptr)
        {
            if (y == nullptr)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == nullptr)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x->Length.CompareTo(y->Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x->CompareTo(y);
                }
            }
        }
    }
};

void Display(List<String^>^ list)
{
    Console::WriteLine();
    for each(String^ s in list)
    {
        Console::WriteLine(s);
    }
};

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();

    dinosaurs->Add("Pachycephalosaurus");
    dinosaurs->Add("Parasauralophus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("Galimimus");
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Deinonychus");
    dinosaurs->Add("Oviraptor");
    dinosaurs->Add("Tyrannosaurus");

    int herbivores = 5;
    Display(dinosaurs);

    DinoComparer^ dc = gcnew DinoComparer();

    Console::WriteLine("\nSort a range with the alternate comparer:");
    dinosaurs->Sort(0, herbivores, dc);
    Display(dinosaurs);

    Console::WriteLine("\nBinarySearch a range and Insert \"{0}\":",
            "Brachiosaurus");

    int index = dinosaurs->BinarySearch(0, herbivores, "Brachiosaurus", dc);

    if (index < 0)
    {
        dinosaurs->Insert(~index, "Brachiosaurus");
        herbivores++;
    }

    Display(dinosaurs);
}

/* This code example produces the following output:

Pachycephalosaurus
Parasauralophus
Amargasaurus
Galimimus
Mamenchisaurus
Deinonychus
Oviraptor
Tyrannosaurus

Sort a range with the alternate comparer:

Galimimus
Amargasaurus
Mamenchisaurus
Parasauralophus
Pachycephalosaurus
Deinonychus
Oviraptor
Tyrannosaurus

BinarySearch a range and Insert "Brachiosaurus":

Galimimus
Amargasaurus
Brachiosaurus
Mamenchisaurus
Parasauralophus
Pachycephalosaurus
Deinonychus
Oviraptor
Tyrannosaurus
 */
using System;
using System.Collections.Generic;

public class DinoComparer: IComparer<string>
{
    public int Compare(string x, string y)
    {
        if (x == null)
        {
            if (y == null)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == null)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x.Length.CompareTo(y.Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x.CompareTo(y);
                }
            }
        }
    }
}

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();

        dinosaurs.Add("Pachycephalosaurus");
        dinosaurs.Add("Parasauralophus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Galimimus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");
        dinosaurs.Add("Oviraptor");
        dinosaurs.Add("Tyrannosaurus");

        int herbivores = 5;
        Display(dinosaurs);

        DinoComparer dc = new DinoComparer();

        Console.WriteLine("\nSort a range with the alternate comparer:");
        dinosaurs.Sort(0, herbivores, dc);
        Display(dinosaurs);

        Console.WriteLine("\nBinarySearch a range and Insert \"{0}\":",
            "Brachiosaurus");

        int index = dinosaurs.BinarySearch(0, herbivores, "Brachiosaurus", dc);

        if (index < 0)
        {
            dinosaurs.Insert(~index, "Brachiosaurus");
            herbivores++;
        }

        Display(dinosaurs);
    }

    private static void Display(List<string> list)
    {
        Console.WriteLine();
        foreach( string s in list )
        {
            Console.WriteLine(s);
        }
    }
}

/* This code example produces the following output:

Pachycephalosaurus
Parasauralophus
Amargasaurus
Galimimus
Mamenchisaurus
Deinonychus
Oviraptor
Tyrannosaurus

Sort a range with the alternate comparer:

Galimimus
Amargasaurus
Mamenchisaurus
Parasauralophus
Pachycephalosaurus
Deinonychus
Oviraptor
Tyrannosaurus

BinarySearch a range and Insert "Brachiosaurus":

Galimimus
Amargasaurus
Brachiosaurus
Mamenchisaurus
Parasauralophus
Pachycephalosaurus
Deinonychus
Oviraptor
Tyrannosaurus
 */
Imports System.Collections.Generic

Public Class DinoComparer
    Implements IComparer(Of String)

    Public Function Compare(ByVal x As String, _
        ByVal y As String) As Integer _
        Implements IComparer(Of String).Compare

        If x Is Nothing Then
            If y Is Nothing Then 
                ' If x is Nothing and y is Nothing, they're
                ' equal. 
                Return 0
            Else
                ' If x is Nothing and y is not Nothing, y
                ' is greater. 
                Return -1
            End If
        Else
            ' If x is not Nothing...
            '
            If y Is Nothing Then
                ' ...and y is Nothing, x is greater.
                Return 1
            Else
                ' ...and y is not Nothing, compare the 
                ' lengths of the two strings.
                '
                Dim retval As Integer = _
                    x.Length.CompareTo(y.Length)

                If retval <> 0 Then 
                    ' If the strings are not of equal length,
                    ' the longer string is greater.
                    '
                    Return retval
                Else
                    ' If the strings are of equal length,
                    ' sort them with ordinary string comparison.
                    '
                    Return x.CompareTo(y)
                End If
            End If
        End If
    End Function
End Class

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Parasauralophus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Galimimus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Deinonychus")
        dinosaurs.Add("Oviraptor")
        dinosaurs.Add("Tyrannosaurus")

        Dim herbivores As Integer = 5
        Display(dinosaurs)

        Dim dc As New DinoComparer

        Console.WriteLine(vbLf & _
            "Sort a range with the alternate comparer:")
        dinosaurs.Sort(0, herbivores, dc)
        Display(dinosaurs)

        Console.WriteLine(vbLf & _
            "BinarySearch a range and Insert ""{0}"":", _
            "Brachiosaurus")

        Dim index As Integer = _
            dinosaurs.BinarySearch(0, herbivores, "Brachiosaurus", dc)

        If index < 0 Then
            index = index Xor -1
            dinosaurs.Insert(index, "Brachiosaurus")
            herbivores += 1
        End If

        Display(dinosaurs)

    End Sub

    Private Shared Sub Display(ByVal lis As List(Of String))
        Console.WriteLine()
        For Each s As String In lis
            Console.WriteLine(s)
        Next
    End Sub
End Class

' This code example produces the following output:
'
'Pachycephalosaurus
'Parasauralophus
'Amargasaurus
'Galimimus
'Mamenchisaurus
'Deinonychus
'Oviraptor
'Tyrannosaurus
'
'Sort a range with the alternate comparer:
'
'Galimimus
'Amargasaurus
'Mamenchisaurus
'Parasauralophus
'Pachycephalosaurus
'Deinonychus
'Oviraptor
'Tyrannosaurus
'
'BinarySearch a range and Insert "Brachiosaurus":
'
'Galimimus
'Amargasaurus
'Brachiosaurus
'Mamenchisaurus
'Parasauralophus
'Pachycephalosaurus
'Deinonychus
'Oviraptor
'Tyrannosaurus

注解

如果comparer提供了, 则使用指定IComparer<T>List<T>实现对的元素进行排序。If comparer is provided, the elements of the List<T> are sorted using the specified IComparer<T> implementation.

如果comparer Comparer<T>.Defaultnull, 则默认比较器将检查T类型是否IComparable<T>实现泛型接口, 并使用该实现 (如果可用)。If comparer is null, the default comparer Comparer<T>.Default checks whether type T implements the IComparable<T> generic interface and uses that implementation, if available. 否则, Comparer<T>.Default将检查类型T是否实现IComparable接口。If not, Comparer<T>.Default checks whether type T implements the IComparable interface. 如果类型T未实现任何一个接口, Comparer<T>.Default则会InvalidOperationException引发。If type T does not implement either interface, Comparer<T>.Default throws an InvalidOperationException.

此方法使用Array.Sort, 它将应用反省排序, 如下所示:This method uses Array.Sort, which applies the introspective sort as follows:

  • 如果分区大小少于16个元素, 则使用插入排序算法If the partition size is fewer than 16 elements, it uses an insertion sort algorithm

  • 如果分区数超过2个 log n, 其中n是输入数组的范围, 则使用Heapsort算法。If the number of partitions exceeds 2 log n, where n is the range of the input array, it uses a Heapsort algorithm.

  • 否则, 它将使用快速排序算法。Otherwise, it uses a Quicksort algorithm.

此实现执行不稳定的排序;也就是说, 如果两个元素相等, 则可能不会保留它们的顺序。This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. 相反, 稳定排序会保留相等元素的顺序。In contrast, a stable sort preserves the order of elements that are equal.

平均而言, 此方法为 o (n log n) 操作, 其中n Count为; 在最坏情况下, 它是一个 o (n2) 操作。On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n2) operation.

另请参阅

Sort() Sort() Sort() Sort()

使用默认比较器对整个 List<T> 中的元素进行排序。Sorts the elements in the entire List<T> using the default comparer.

public:
 void Sort();
public void Sort ();
member this.Sort : unit -> unit
Public Sub Sort ()

异常

此默认比较器 Default 无法找到 IComparable<T> 泛型接口或类型为 TIComparable 接口的实现。The default comparer Default cannot find an implementation of the IComparable<T> generic interface or the IComparable interface for type T.

示例

下面的示例向List<String>对象添加一些名称, 以未排序的顺序显示列表, Sort调用方法, 然后显示已排序的列表。The following example adds some names to a List<String> object, displays the list in unsorted order, calls the Sort method, and then displays the sorted list.

using System;
using System.Collections.Generic;

public class Example
{
   public static void Main()
   {
      String[] names = { "Samuel", "Dakota", "Koani", "Saya", "Vanya", "Jody",
                         "Yiska", "Yuma", "Jody", "Nikita" };
      var nameList = new List<String>();
      nameList.AddRange(names);
      Console.WriteLine("List in unsorted order: ");
      foreach (var name in nameList)
         Console.Write("   {0}", name);

      Console.WriteLine(Environment.NewLine);

      nameList.Sort();
      Console.WriteLine("List in sorted order: ");
      foreach (var name in nameList)
         Console.Write("   {0}", name);

      Console.WriteLine();
   }
}
// The example displays the following output:
//    List in unsorted order:
//       Samuel   Dakota   Koani   Saya   Vanya   Jody   Yiska   Yuma   Jody   Nikita
//
//    List in sorted order:
//       Dakota   Jody   Jody   Koani   Nikita   Samuel   Saya   Vanya   Yiska   Yuma
Imports System.Collections.Generic

Module Example
   Public Sub Main()
      Dim names() As String = { "Samuel", "Dakota", "Koani", "Saya",
                                "Vanya", "Jody", "Yiska", "Yuma", 
                                "Jody", "Nikita" }
      Dim nameList As New List(Of String)()
      nameList.AddRange(names)
      Console.WriteLine("List in unsorted order: ")
      For Each name In nameList
         Console.Write("   {0}", name)
      Next
      Console.WriteLine(vbCrLf)

      nameList.Sort()
      Console.WriteLine("List in sorted order: ")
      For Each name In nameList
         Console.Write("   {0}", name)
      Next
      Console.WriteLine()
    End Sub
End Module
' The example displays the following output:
'    List in unsorted order:
'       Samuel   Dakota   Koani   Saya   Vanya   Jody   Yiska   Yuma   Jody   Nikita
'
'    List in sorted order:
'       Dakota   Jody   Jody   Koani   Nikita   Samuel   Saya   Vanya   Yiska   Yuma

下面的代码演示简单Sort()业务Sort(Comparison<T>)对象上的和方法重载。The following code demonstrates the Sort() and Sort(Comparison<T>) method overloads on a simple business object. 调用方法会导致为部件类型使用默认比较器, Sort(Comparison<T>)并使用匿名方法实现方法。 Sort()Calling the Sort() method results in the use of the default comparer for the Part type, and the Sort(Comparison<T>) method is implemented by using an anonymous method.

using System;
using System.Collections.Generic;
// Simple business object. A PartId is used to identify the type of part 
// but the part name can change. 
public class Part : IEquatable<Part> , IComparable<Part>
{
    public string PartName { get; set; }

    public int PartId { get; set; }

    public override string ToString()
    {
        return "ID: " + PartId + "   Name: " + PartName;
    }
    public override bool Equals(object obj)
    {
        if (obj == null) return false;
        Part objAsPart = obj as Part;
        if (objAsPart == null) return false;
        else return Equals(objAsPart);
    }
    public int SortByNameAscending(string name1, string name2)
    {
        
        return name1.CompareTo(name2);
    }

    // Default comparer for Part type.
    public int CompareTo(Part comparePart)
    {
          // A null value means that this object is greater.
        if (comparePart == null)
            return 1;
            
        else
            return this.PartId.CompareTo(comparePart.PartId);
    }
    public override int GetHashCode()
    {
        return PartId;
    }
    public bool Equals(Part other)
    {
        if (other == null) return false;
        return (this.PartId.Equals(other.PartId));
    }
    // Should also override == and != operators.

}
public class Example
{
    public static void Main()
    {
        // Create a list of parts.
        List<Part> parts = new List<Part>();

        // Add parts to the list.
        parts.Add(new Part() { PartName = "regular seat", PartId = 1434 });
        parts.Add(new Part() { PartName= "crank arm", PartId = 1234 });
        parts.Add(new Part() { PartName = "shift lever", PartId = 1634 }); ;
        // Name intentionally left null.
        parts.Add(new Part() {  PartId = 1334 });
        parts.Add(new Part() { PartName = "banana seat", PartId = 1444 });
        parts.Add(new Part() { PartName = "cassette", PartId = 1534 });
       

        // Write out the parts in the list. This will call the overridden 
        // ToString method in the Part class.
        Console.WriteLine("\nBefore sort:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }


        // Call Sort on the list. This will use the 
        // default comparer, which is the Compare method 
        // implemented on Part.
        parts.Sort();


        Console.WriteLine("\nAfter sort by part number:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }
       
        // This shows calling the Sort(Comparison(T) overload using 
        // an anonymous method for the Comparison delegate. 
        // This method treats null as the lesser of two values.
        parts.Sort(delegate(Part x, Part y)
        {
            if (x.PartName == null && y.PartName == null) return 0;
            else if (x.PartName == null) return -1;
            else if (y.PartName == null) return 1;
            else return x.PartName.CompareTo(y.PartName);
        });

        Console.WriteLine("\nAfter sort by name:");
        foreach (Part aPart in parts)
        {
            Console.WriteLine(aPart);
        }
       
        /*
       
            Before sort:
        ID: 1434   Name: regular seat
        ID: 1234   Name: crank arm
        ID: 1634   Name: shift lever
        ID: 1334   Name:
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette

        After sort by part number:
        ID: 1234   Name: crank arm
        ID: 1334   Name:
        ID: 1434   Name: regular seat
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette
        ID: 1634   Name: shift lever

        After sort by name:
        ID: 1334   Name:
        ID: 1444   Name: banana seat
        ID: 1534   Name: cassette
        ID: 1234   Name: crank arm
        ID: 1434   Name: regular seat
        ID: 1634   Name: shift lever

         */

    }
}
Imports System.Collections.Generic

' Simple business object. A PartId is used to identify the type of part 
' but the part name can change. 
Public Class Part
    Implements IEquatable(Of Part)
    Implements IComparable(Of Part)
    Public Property PartName() As String
        Get
            Return m_PartName
        End Get
        Set(value As String)
            m_PartName = Value
        End Set
    End Property
    Private m_PartName As String

    Public Property PartId() As Integer
        Get
            Return m_PartId
        End Get
        Set(value As Integer)
            m_PartId = Value
        End Set
    End Property
    Private m_PartId As Integer

    Public Overrides Function ToString() As String
        Return "ID: " & PartId & "   Name: " & PartName
    End Function

    Public Overrides Function Equals(obj As Object) As Boolean
        If obj Is Nothing Then
            Return False
        End If
        Dim objAsPart As Part = TryCast(obj, Part)
        If objAsPart Is Nothing Then
            Return False
        Else
            Return Equals(objAsPart)
        End If
    End Function

    Public Function SortByNameAscending(name1 As String, name2 As String) As Integer

        Return name1.CompareTo(name2)
    End Function

    ' Default comparer for Part.
    Public Function CompareTo(comparePart As Part) As Integer _
            Implements IComparable(Of ListSortVB.Part).CompareTo
        ' A null value means that this object is greater.
        If comparePart Is Nothing Then
            Return 1
        Else

            Return Me.PartId.CompareTo(comparePart.PartId)
        End If
    End Function
    Public Overrides Function GetHashCode() As Integer
        Return PartId
    End Function
    Public Overloads Function Equals(other As Part) As Boolean Implements IEquatable(Of ListSortVB.Part).Equals
        If other Is Nothing Then
            Return False
        End If
        Return (Me.PartId.Equals(other.PartId))
    End Function
    ' Should also override == and != operators.

End Class
Public Class Example
    Public Shared Sub Main()
        ' Create a list of parts.
        Dim parts As New List(Of Part)()

        ' Add parts to the list.
        parts.Add(New Part() With { _
             .PartName = "regular seat", _
             .PartId = 1434 _
        })
        parts.Add(New Part() With { _
             .PartName = "crank arm", _
             .PartId = 1234 _
        })
        parts.Add(New Part() With { _
             .PartName = "shift lever", _
             .PartId = 1634 _
        })


        ' Name intentionally left null.
        parts.Add(New Part() With { _
             .PartId = 1334 _
        })
        parts.Add(New Part() With { _
             .PartName = "banana seat", _
             .PartId = 1444 _
        })
        parts.Add(New Part() With { _
             .PartName = "cassette", _
             .PartId = 1534 _
        })


        ' Write out the parts in the list. This will call the overridden 
        ' ToString method in the Part class.
        Console.WriteLine(vbLf & "Before sort:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next


        ' Call Sort on the list. This will use the 
        ' default comparer, which is the Compare method 
        ' implemented on Part.
        parts.Sort()


        Console.WriteLine(vbLf & "After sort by part number:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next

        ' This shows calling the Sort(Comparison(T) overload using 
        ' an anonymous delegate method. 
        ' This method treats null as the lesser of two values.
        parts.Sort(Function(x As Part, y As Part)
                             If x.PartName Is Nothing AndAlso y.PartName Is Nothing Then
                                 Return 0
                             ElseIf x.PartName Is Nothing Then
                                 Return -1
                             ElseIf y.PartName Is Nothing Then
                                 Return 1
                             Else
                                 Return x.PartName.CompareTo(y.PartName)
                             End If
                         End Function)
        

        Console.WriteLine(vbLf & "After sort by name:")
        For Each aPart As Part In parts
            Console.WriteLine(aPart)
        Next

        '
        '        
        '            Before sort:
        '            ID: 1434   Name: regular seat
        '            ID: 1234   Name: crank arm
        '            ID: 1634   Name: shift lever
        '            ID: 1334   Name:
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '
        '            After sort by part number:
        '            ID: 1234   Name: crank arm
        '            ID: 1334   Name:
        '            ID: 1434   Name: regular seat
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '            ID: 1634   Name: shift lever
        '
        '            After sort by name:
        '            ID: 1334   Name:
        '            ID: 1444   Name: banana seat
        '            ID: 1534   Name: cassette
        '            ID: 1234   Name: crank arm
        '            ID: 1434   Name: regular seat
        '            ID: 1634   Name: shift lever

    End Sub
End Class

下面的示例演示Sort()方法重载BinarySearch(T)和方法重载。The following example demonstrates the Sort() method overload and the BinarySearch(T) method overload. List<T>创建一个字符串, 并以无特定顺序填充四个字符串。A List<T> of strings is created and populated with four strings, in no particular order. 将显示并排序列表, 并再次显示该列表。The list is displayed, sorted, and displayed again.

然后, 使用Insert 方法重载搜索两个不在列表中的字符串,该方法BinarySearch(T)用于插入它们。The BinarySearch(T) method overload is then used to search for two strings that are not in the list, and the Insert method is used to insert them. 在每种情况下BinarySearch , 方法的返回值为负, 因为字符串不在列表中。The return value of the BinarySearch method is negative in each case, because the strings are not in the list. 采用按位求补 ( C#和视觉对象C++中的 ~ Xor运算符, Visual Basic 中的), 此负数将生成列表中大于搜索字符串的第一个元素的索引, 并在此位置插入保留排序顺序。Taking the bitwise complement (the ~ operator in C# and Visual C++, Xor -1 in Visual Basic) of this negative number produces the index of the first element in the list that is larger than the search string, and inserting at this location preserves the sort order. 第二个搜索字符串大于列表中的任何元素, 因此插入位置在列表的末尾。The second search string is larger than any element in the list, so the insertion position is at the end of the list.

using namespace System;
using namespace System::Collections::Generic;

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();

    dinosaurs->Add("Pachycephalosaurus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Deinonychus");

    Console::WriteLine();
    for each(String^ dinosaur in dinosaurs)
    {
        Console::WriteLine(dinosaur);
    }

    Console::WriteLine("\nSort");
    dinosaurs->Sort();

    Console::WriteLine();
    for each(String^ dinosaur in dinosaurs)
    {
        Console::WriteLine(dinosaur);
    }

    Console::WriteLine("\nBinarySearch and Insert \"Coelophysis\":");
    int index = dinosaurs->BinarySearch("Coelophysis");
    if (index < 0)
    {
        dinosaurs->Insert(~index, "Coelophysis");
    }

    Console::WriteLine();
    for each(String^ dinosaur in dinosaurs)
    {
        Console::WriteLine(dinosaur);
    }

    Console::WriteLine("\nBinarySearch and Insert \"Tyrannosaurus\":");
    index = dinosaurs->BinarySearch("Tyrannosaurus");
    if (index < 0)
    {
        dinosaurs->Insert(~index, "Tyrannosaurus");
    }

    Console::WriteLine();
    for each(String^ dinosaur in dinosaurs)
    {
        Console::WriteLine(dinosaur);
    }
}

/* This code example produces the following output:

Pachycephalosaurus
Amargasaurus
Mamenchisaurus
Deinonychus

Sort

Amargasaurus
Deinonychus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Coelophysis":

Amargasaurus
Coelophysis
Deinonychus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Tyrannosaurus":

Amargasaurus
Coelophysis
Deinonychus
Mamenchisaurus
Pachycephalosaurus
Tyrannosaurus
 */
using System;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();

        dinosaurs.Add("Pachycephalosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\nSort");
        dinosaurs.Sort();

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\nBinarySearch and Insert \"Coelophysis\":");
        int index = dinosaurs.BinarySearch("Coelophysis");
        if (index < 0)
        {
            dinosaurs.Insert(~index, "Coelophysis");
        }

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }

        Console.WriteLine("\nBinarySearch and Insert \"Tyrannosaurus\":");
        index = dinosaurs.BinarySearch("Tyrannosaurus");
        if (index < 0)
        {
            dinosaurs.Insert(~index, "Tyrannosaurus");
        }

        Console.WriteLine();
        foreach(string dinosaur in dinosaurs)
        {
            Console.WriteLine(dinosaur);
        }
    }
}

/* This code example produces the following output:

Pachycephalosaurus
Amargasaurus
Mamenchisaurus
Deinonychus

Sort

Amargasaurus
Deinonychus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Coelophysis":

Amargasaurus
Coelophysis
Deinonychus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Tyrannosaurus":

Amargasaurus
Coelophysis
Deinonychus
Mamenchisaurus
Pachycephalosaurus
Tyrannosaurus
 */
Imports System.Collections.Generic

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)

        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Deinonychus")

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & "Sort")
        dinosaurs.Sort

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "BinarySearch and Insert ""Coelophysis"":")
        Dim index As Integer = dinosaurs.BinarySearch("Coelophysis")
        If index < 0 Then
            index = index Xor -1
            dinosaurs.Insert(index, "Coelophysis")
        End If

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

        Console.WriteLine(vbLf & _
            "BinarySearch and Insert ""Tyrannosaurus"":")
        index = dinosaurs.BinarySearch("Tyrannosaurus")
        If index < 0 Then
            index = index Xor -1
            dinosaurs.Insert(index, "Tyrannosaurus")
        End If

        Console.WriteLine()
        For Each dinosaur As String In dinosaurs
            Console.WriteLine(dinosaur)
        Next

    End Sub
End Class

' This code example produces the following output:
'
'Pachycephalosaurus
'Amargasaurus
'Mamenchisaurus
'Deinonychus
'
'Sort
'
'Amargasaurus
'Deinonychus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Coelophysis":
'
'Amargasaurus
'Coelophysis
'Deinonychus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Tyrannosaurus":
'
'Amargasaurus
'Coelophysis
'Deinonychus
'Mamenchisaurus
'Pachycephalosaurus
'Tyrannosaurus

注解

此方法使用类型Comparer<T>.Default T的默认比较器来确定列表元素的顺序。This method uses the default comparer Comparer<T>.Default for type T to determine the order of list elements. 属性检查类型T是否实现IComparable<T>泛型接口, 并使用该实现 (如果可用)。 Comparer<T>.DefaultThe Comparer<T>.Default property checks whether type T implements the IComparable<T> generic interface and uses that implementation, if available. 否则, Comparer<T>.Default将检查类型T是否实现IComparable接口。If not, Comparer<T>.Default checks whether type T implements the IComparable interface. 如果类型T未实现任何一个接口, Comparer<T>.Default则会InvalidOperationException引发。If type T does not implement either interface, Comparer<T>.Default throws an InvalidOperationException.

此方法使用Array.Sort方法, 该方法应用反省排序, 如下所示:This method uses the Array.Sort method, which applies the introspective sort as follows:

  • 如果分区大小少于16个, 则使用插入排序算法。If the partition size is fewer than 16 elements, it uses an insertion sort algorithm.

  • 如果分区数超过2个 log n, 其中n是输入数组的范围, 则使用 Heapsort 算法。If the number of partitions exceeds 2 log n, where n is the range of the input array, it uses a Heapsort algorithm.

  • 否则, 它将使用快速排序算法。Otherwise, it uses a Quicksort algorithm.

此实现执行不稳定的排序;也就是说, 如果两个元素相等, 则可能不会保留它们的顺序。This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. 相反, 稳定排序会保留相等元素的顺序。In contrast, a stable sort preserves the order of elements that are equal.

平均而言, 此方法为 o (n log n) 操作, 其中n Count为; 在最坏情况下, 它是一个 o (n2) 操作。On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n2) operation.

另请参阅

Sort(IComparer<T>) Sort(IComparer<T>) Sort(IComparer<T>) Sort(IComparer<T>)

使用指定的比较器对整个 List<T> 中的元素进行排序。Sorts the elements in the entire List<T> using the specified comparer.

public:
 void Sort(System::Collections::Generic::IComparer<T> ^ comparer);
public void Sort (System.Collections.Generic.IComparer<T> comparer);
member this.Sort : System.Collections.Generic.IComparer<'T> -> unit
Public Sub Sort (comparer As IComparer(Of T))

参数

comparer
IComparer<T> IComparer<T> IComparer<T> IComparer<T>

比较元素时要使用的 IComparer<T> 实现,若要使用默认比较器 Default,则为 nullThe IComparer<T> implementation to use when comparing elements, or null to use the default comparer Default.

异常

comparernull,且默认比较器 Default 找不到 IComparable<T> 泛型接口或类型为 TIComparable 接口的实现。comparer is null, and the default comparer Default cannot find implementation of the IComparable<T> generic interface or the IComparable interface for type T.

comparer 的实现导致排序时出现错误。The implementation of comparer caused an error during the sort. 例如,将某个项与其自身比较时,comparer 可能不返回 0。For example, comparer might not return 0 when comparing an item with itself.

示例

下面的示例演示Sort(IComparer<T>)方法重载BinarySearch(T, IComparer<T>)和方法重载。The following example demonstrates the Sort(IComparer<T>) method overload and the BinarySearch(T, IComparer<T>) method overload.

该示例定义了一个名为 DinoCompare 的字符串的替代比较器IComparer<string> ,IComparer(Of String)该比较器IComparer<String^>实现了C++(在 Visual Basic 中的 Visual) 泛型接口。The example defines an alternative comparer for strings named DinoCompare, which implements the IComparer<string> (IComparer(Of String) in Visual Basic, IComparer<String^> in Visual C++) generic interface. 比较器的工作方式如下:首先, 对这些比较的值null进行测试, 并将空引用视为小于非空引用。The comparer works as follows: First, the comparands are tested for null, and a null reference is treated as less than a non-null. 其次, 比较字符串长度, 较长的字符串被认为更大。Second, the string lengths are compared, and the longer string is deemed to be greater. 第三, 如果长度相等, 则使用普通字符串比较。Third, if the lengths are equal, ordinary string comparison is used.

List<T>创建一个字符串, 并以无特定顺序填充四个字符串。A List<T> of strings is created and populated with four strings, in no particular order. 随即显示列表, 使用替代比较器对其进行排序, 并再次显示。The list is displayed, sorted using the alternate comparer, and displayed again.

然后, 使用方法重载搜索多个不在列表中的字符串 (采用备用比较器)。 BinarySearch(T, IComparer<T>)The BinarySearch(T, IComparer<T>) method overload is then used to search for several strings that are not in the list, employing the alternate comparer. Insert方法用于插入字符串。The Insert method is used to insert the strings. 这两个方法SearchAndInsert都位于名为的函数中, 同时还包含用于采用按位求补的代码 (Visual Basic 和Xor C# C++中的 ~ 运算符), BinarySearch(T, IComparer<T>)并使用返回的负数作为用于插入新字符串的索引。These two methods are located in the function named SearchAndInsert, along with code to take the bitwise complement (the ~ operator in C# and Visual C++, Xor -1 in Visual Basic) of the negative number returned by BinarySearch(T, IComparer<T>) and use it as an index for inserting the new string.

using namespace System;
using namespace System::Collections::Generic;

public ref class DinoComparer: IComparer<String^>
{
public:
    virtual int Compare(String^ x, String^ y)
    {
        if (x == nullptr)
        {
            if (y == nullptr)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == nullptr)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x->Length.CompareTo(y->Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x->CompareTo(y);
                }
            }
        }
    }
};

void SearchAndInsert(List<String^>^ list, String^ insert, 
    DinoComparer^ dc)
{
    Console::WriteLine("\nBinarySearch and Insert \"{0}\":", insert);

    int index = list->BinarySearch(insert, dc);

    if (index < 0)
    {
        list->Insert(~index, insert);
    }
};

void Display(List<String^>^ list)
{
    Console::WriteLine();
    for each(String^ s in list)
    {
        Console::WriteLine(s);
    }
};

void main()
{
    List<String^>^ dinosaurs = gcnew List<String^>();
    dinosaurs->Add("Pachycephalosaurus");
    dinosaurs->Add("Amargasaurus");
    dinosaurs->Add("Mamenchisaurus");
    dinosaurs->Add("Deinonychus");
    Display(dinosaurs);

    DinoComparer^ dc = gcnew DinoComparer();

    Console::WriteLine("\nSort with alternate comparer:");
    dinosaurs->Sort(dc);
    Display(dinosaurs);

    SearchAndInsert(dinosaurs, "Coelophysis", dc);
    Display(dinosaurs);

    SearchAndInsert(dinosaurs, "Oviraptor", dc);
    Display(dinosaurs);

    SearchAndInsert(dinosaurs, "Tyrannosaur", dc);
    Display(dinosaurs);

    SearchAndInsert(dinosaurs, nullptr, dc);
    Display(dinosaurs);
}

/* This code example produces the following output:

Pachycephalosaurus
Amargasaurus
Mamenchisaurus
Deinonychus

Sort with alternate comparer:

Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Coelophysis":

Coelophysis
Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Oviraptor":

Oviraptor
Coelophysis
Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Tyrannosaur":

Oviraptor
Coelophysis
Deinonychus
Tyrannosaur
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "":


Oviraptor
Coelophysis
Deinonychus
Tyrannosaur
Amargasaurus
Mamenchisaurus
Pachycephalosaurus
 */
using System;
using System.Collections.Generic;

public class DinoComparer: IComparer<string>
{
    public int Compare(string x, string y)
    {
        if (x == null)
        {
            if (y == null)
            {
                // If x is null and y is null, they're
                // equal. 
                return 0;
            }
            else
            {
                // If x is null and y is not null, y
                // is greater. 
                return -1;
            }
        }
        else
        {
            // If x is not null...
            //
            if (y == null)
                // ...and y is null, x is greater.
            {
                return 1;
            }
            else
            {
                // ...and y is not null, compare the 
                // lengths of the two strings.
                //
                int retval = x.Length.CompareTo(y.Length);

                if (retval != 0)
                {
                    // If the strings are not of equal length,
                    // the longer string is greater.
                    //
                    return retval;
                }
                else
                {
                    // If the strings are of equal length,
                    // sort them with ordinary string comparison.
                    //
                    return x.CompareTo(y);
                }
            }
        }
    }
}

public class Example
{
    public static void Main()
    {
        List<string> dinosaurs = new List<string>();
        dinosaurs.Add("Pachycephalosaurus");
        dinosaurs.Add("Amargasaurus");
        dinosaurs.Add("Mamenchisaurus");
        dinosaurs.Add("Deinonychus");
        Display(dinosaurs);

        DinoComparer dc = new DinoComparer();

        Console.WriteLine("\nSort with alternate comparer:");
        dinosaurs.Sort(dc);
        Display(dinosaurs);

        SearchAndInsert(dinosaurs, "Coelophysis", dc);
        Display(dinosaurs);

        SearchAndInsert(dinosaurs, "Oviraptor", dc);
        Display(dinosaurs);

        SearchAndInsert(dinosaurs, "Tyrannosaur", dc);
        Display(dinosaurs);

        SearchAndInsert(dinosaurs, null, dc);
        Display(dinosaurs);
    }

    private static void SearchAndInsert(List<string> list, 
        string insert, DinoComparer dc)
    {
        Console.WriteLine("\nBinarySearch and Insert \"{0}\":", insert);

        int index = list.BinarySearch(insert, dc);

        if (index < 0)
        {
            list.Insert(~index, insert);
        }
    }

    private static void Display(List<string> list)
    {
        Console.WriteLine();
        foreach( string s in list )
        {
            Console.WriteLine(s);
        }
    }
}

/* This code example produces the following output:

Pachycephalosaurus
Amargasaurus
Mamenchisaurus
Deinonychus

Sort with alternate comparer:

Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Coelophysis":

Coelophysis
Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Oviraptor":

Oviraptor
Coelophysis
Deinonychus
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "Tyrannosaur":

Oviraptor
Coelophysis
Deinonychus
Tyrannosaur
Amargasaurus
Mamenchisaurus
Pachycephalosaurus

BinarySearch and Insert "":


Oviraptor
Coelophysis
Deinonychus
Tyrannosaur
Amargasaurus
Mamenchisaurus
Pachycephalosaurus
 */
Imports System.Collections.Generic

Public Class DinoComparer
    Implements IComparer(Of String)

    Public Function Compare(ByVal x As String, _
        ByVal y As String) As Integer _
        Implements IComparer(Of String).Compare

        If x Is Nothing Then
            If y Is Nothing Then 
                ' If x is Nothing and y is Nothing, they're
                ' equal. 
                Return 0
            Else
                ' If x is Nothing and y is not Nothing, y
                ' is greater. 
                Return -1
            End If
        Else
            ' If x is not Nothing...
            '
            If y Is Nothing Then
                ' ...and y is Nothing, x is greater.
                Return 1
            Else
                ' ...and y is not Nothing, compare the 
                ' lengths of the two strings.
                '
                Dim retval As Integer = _
                    x.Length.CompareTo(y.Length)

                If retval <> 0 Then 
                    ' If the strings are not of equal length,
                    ' the longer string is greater.
                    '
                    Return retval
                Else
                    ' If the strings are of equal length,
                    ' sort them with ordinary string comparison.
                    '
                    Return x.CompareTo(y)
                End If
            End If
        End If
    End Function
End Class

Public Class Example

    Public Shared Sub Main()

        Dim dinosaurs As New List(Of String)
        dinosaurs.Add("Pachycephalosaurus")
        dinosaurs.Add("Amargasaurus")
        dinosaurs.Add("Mamenchisaurus")
        dinosaurs.Add("Deinonychus")
        Display(dinosaurs)

        Dim dc As New DinoComparer

        Console.WriteLine(vbLf & "Sort with alternate comparer:")
        dinosaurs.Sort(dc)
        Display(dinosaurs)

        SearchAndInsert(dinosaurs, "Coelophysis", dc)
        Display(dinosaurs)

        SearchAndInsert(dinosaurs, "Oviraptor", dc)
        Display(dinosaurs)

        SearchAndInsert(dinosaurs, "Tyrannosaur", dc)
        Display(dinosaurs)

        SearchAndInsert(dinosaurs, Nothing, dc)
        Display(dinosaurs)
    End Sub

    Private Shared Sub SearchAndInsert( _
        ByVal lis As List(Of String), _
        ByVal insert As String, ByVal dc As DinoComparer)

        Console.WriteLine(vbLf & _
            "BinarySearch and Insert ""{0}"":", insert)

        Dim index As Integer = lis.BinarySearch(insert, dc)

        If index < 0 Then
            index = index Xor -1
            lis.Insert(index, insert)
        End If
    End Sub

    Private Shared Sub Display(ByVal lis As List(Of String))
        Console.WriteLine()
        For Each s As String In lis
            Console.WriteLine(s)
        Next
    End Sub
End Class

' This code example produces the following output:
'
'Pachycephalosaurus
'Amargasaurus
'Mamenchisaurus
'Deinonychus
'
'Sort with alternate comparer:
'
'Deinonychus
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Coelophysis":
'
'Coelophysis
'Deinonychus
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Oviraptor":
'
'Oviraptor
'Coelophysis
'Deinonychus
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "Tyrannosaur":
'
'Oviraptor
'Coelophysis
'Deinonychus
'Tyrannosaur
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus
'
'BinarySearch and Insert "":
'
'
'Oviraptor
'Coelophysis
'Deinonychus
'Tyrannosaur
'Amargasaurus
'Mamenchisaurus
'Pachycephalosaurus

注解

如果comparer提供了, 则使用指定IComparer<T>List<T>实现对的元素进行排序。If comparer is provided, the elements of the List<T> are sorted using the specified IComparer<T> implementation.

如果comparer Comparer<T>.Defaultnull, 则默认比较器将检查T类型是否IComparable<T>实现泛型接口, 并使用该实现 (如果可用)。If comparer is null, the default comparer Comparer<T>.Default checks whether type T implements the IComparable<T> generic interface and uses that implementation, if available. 否则, Comparer<T>.Default将检查类型T是否实现IComparable接口。If not, Comparer<T>.Default checks whether type T implements the IComparable interface. 如果类型T未实现任何一个接口, Comparer<T>.Default则会InvalidOperationException引发。If type T does not implement either interface, Comparer<T>.Default throws an InvalidOperationException.

此方法使用Array.Sort方法, 该方法应用反省排序, 如下所示:This method uses the Array.Sort method, which applies the introspective sort as follows:

  • 如果分区大小少于16个, 则使用插入排序算法。If the partition size is fewer than 16 elements, it uses an insertion sort algorithm.

  • 如果分区数超过2个 log n, 其中n是输入数组的范围, 则使用 Heapsort 算法。If the number of partitions exceeds 2 log n, where n is the range of the input array, it uses a Heapsort algorithm.

  • 否则, 它将使用快速排序算法。Otherwise, it uses a Quicksort algorithm.

此实现执行不稳定的排序;也就是说, 如果两个元素相等, 则可能不会保留它们的顺序。This implementation performs an unstable sort; that is, if two elements are equal, their order might not be preserved. 相反, 稳定排序会保留相等元素的顺序。In contrast, a stable sort preserves the order of elements that are equal.

平均而言, 此方法为 o (n log n) 操作, 其中n Count为; 在最坏情况下, 它是一个 o (n2) 操作。On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n2) operation.

另请参阅

适用于