Tuple<T1>.IStructuralComparable.CompareTo(Object, IComparer) 方法

定义

使用指定的比较器将当前的 Tuple<T1> 对象与指定对象进行比较,并返回一个整数,该整数指示当前对象在排序顺序中的位置是在指定对象之前、之后还是与其相同。Compares the current Tuple<T1> object to a specified object by using a specified comparer, and returns an integer that indicates whether the current object is before, after, or in the same position as the specified object in the sort order.

 virtual int System.Collections.IStructuralComparable.CompareTo(System::Object ^ other, System::Collections::IComparer ^ comparer) = System::Collections::IStructuralComparable::CompareTo;
int IStructuralComparable.CompareTo (object other, System.Collections.IComparer comparer);
Function CompareTo (other As Object, comparer As IComparer) As Integer Implements IStructuralComparable.CompareTo

参数

other
Object

要与当前实例进行比较的对象。An object to compare with the current instance.

comparer
IComparer

提供用于比较的自定义规则的对象。An object that provides custom rules for comparison.

返回

一个带符号整数,指示此实例和 other 在排序顺序中的相对位置,如下表所示。A signed integer that indicates the relative position of this instance and other in the sort order, as shown in the following table.

Value 说明Description
负整数A negative integer 此实例位于 other 之前。This instance precedes other.
Zero 此实例在排序顺序中的位置与 other 相同。This instance and other have the same position in the sort order.
正整数A positive integer 此实例位于 other 之后。This instance follows other.

实现

异常

other 不是 Tuple<T1> 对象。other is not a Tuple<T1> object.

示例

下面的示例定义了一个名为DescendingComparer的泛型类IComparer<T> , 该类实现接口。The following example defines a generic class named DescendingComparer that implements the IComparer<T> interface. DescendingComparer通过反转特定类型的默认比较器返回的值, 对对象进行降序排序, 而不是按升序排序。DescendingComparer sorts objects in descending rather than ascending order by reversing the value returned by the default comparer for a particular type. 然后, 将泛型DescendingComparer类的实例传递Array.Sort(Array, IComparer)给方法Tuple<T1> , 以便按降序对对象数组进行排序。An instance of the generic DescendingComparer class is then passed to the Array.Sort(Array, IComparer) method to sort an array of Tuple<T1> objects in descending order. 请注意, 该示例不会直接调用IStructuralComparable.CompareTo方法。Note that the example does not directly call the IStructuralComparable.CompareTo method. 此方法由Array.Sort(Array, IComparer)方法为数组中的每个元素隐式调用。This method is called implicitly by the Array.Sort(Array, IComparer) method for each element in the array.

using System;
using System.Collections.Generic;

public class DescendingComparer<T> : IComparer<T>
{
    public int Compare(T x, T y) 
    {
        return -1 * Comparer<T>.Default.Compare(x, y);
    }
}

class CompareTo2
{
   static void Main()
   {
       Tuple<Double>[] values = { Tuple.Create(13.54),
                                  Tuple.Create(Double.NaN),
                                  Tuple.Create(-189.42993),
                                  Tuple.Create(Double.PositiveInfinity),
                                  Tuple.Create(Double.Epsilon),
                                  Tuple.Create(1.934E-17),
                                  Tuple.Create(Double.NegativeInfinity),
                                  Tuple.Create(-0.000000000003588),
                                  null };
       Console.WriteLine("The values in unsorted order:");
       foreach (var value in values)
           if (value != null)
               Console.WriteLine("   {0}", value.Item1);
           else
               Console.WriteLine("   <null>");
       Console.WriteLine();

       Array.Sort(values, new DescendingComparer<Tuple<Double>>());

       Console.WriteLine("The values sorted in descending order:");
       foreach (var value in values)
           if (value != null)
               Console.WriteLine("   {0}", value.Item1);
           else
               Console.WriteLine("   <null>");
    }
}
// The example displays the following output:
//      The values in unsorted order:
//         13.54
//         NaN
//         -189.42993
//         Infinity
//         4.94065645841247E-324
//         1.934E-17
//         -Infinity
//         -3.588E-12
//
//      The values sorted in descending order:
//         Infinity
//         13.54
//         1.934E-17
//         4.94065645841247E-324
//         -3.588E-12
//         -189.42993
//         -Infinity
//         NaN
Imports System.Collections.Generic

Public Class DescendingComparer(Of T) : Implements IComparer(Of T)
    Public Function Compare(ByVal x As T, ByVal y As T) As Integer Implements IComparer(Of T).Compare
        Return -1 * Comparer(Of T).Default.Compare(x, y)
    End Function
End Class

Module Example
    Sub Main()
        Dim values() = { Tuple.Create(13.54),
                         Tuple.Create(Double.NaN),
                         Tuple.Create(-189.42993),
                         Tuple.Create(Double.PositiveInfinity),
                         Tuple.Create(Double.Epsilon),
                         Tuple.Create(1.934E-17),
                         Tuple.Create(Double.NegativeInfinity),
                         Tuple.Create(-0.000000000003588),
                         Nothing}

        Console.WriteLine("The values in unsorted order:")
        For Each value As Tuple(Of Double) In values
            If value IsNot Nothing Then
                Console.WriteLine("   {0}", value.Item1)
            Else
                Console.WriteLine("   <null>")
            End If
        Next
        Console.WriteLine()

        Array.Sort(values, New DescendingComparer(Of Tuple(Of Double)))

        Console.WriteLine("The values sorted in descending order:")
        For Each value As Tuple(Of Double) In values
            If value IsNot Nothing Then
                Console.WriteLine("   {0}", value.Item1)
            Else
                Console.WriteLine("   <null>")
            End If
        Next
    End Sub
End Module
' The example displays the following output:
'      The values in unsorted order:
'         13.54
'         NaN
'         -189.42993
'         Infinity
'         4.94065645841247E-324
'         1.934E-17
'         -Infinity
'         -3.588E-12
'
'      The values sorted in descending order:
'         Infinity
'         13.54
'         1.934E-17
'         4.94065645841247E-324
'         -3.588E-12
'         -189.42993
'         -Infinity
'         NaN

注解

尽管可以直接调用此方法, 但它最常见的方法是包含IComparer参数的集合排序方法, 以对集合的成员进行排序。Although this method can be called directly, it is most commonly called by collection sorting methods that include IComparer parameters to order the members of a collection. 例如, 它Array.Sort(Array, IComparer)由方法Add和使用SortedList.SortedList(IComparer)构造函数实例化的SortedList对象的方法调用。For example, it is called by the Array.Sort(Array, IComparer) method and the Add method of a SortedList object that is instantiated by using the SortedList.SortedList(IComparer) constructor.

注意

IStructuralComparable.CompareTo方法旨在用于排序操作。The IStructuralComparable.CompareTo method is intended for use in sorting operations. 如果比较的主要目的是确定两个对象是否相等, 则不应使用此方法。It should not be used when the primary purpose of a comparison is to determine whether two objects are equal. 若要确定两个对象是否相等, 请IStructuralEquatable.Equals调用方法。To determine whether two objects are equal, call the IStructuralEquatable.Equals method.

适用于

另请参阅