IList 接口
定义
表示可按照索引单独访问的对象的非泛型集合。Represents a non-generic collection of objects that can be individually accessed by index.
public interface class IList : System::Collections::ICollectionpublic interface IList : System.Collections.ICollection[System.Runtime.InteropServices.ComVisible(true)]
public interface IList : System.Collections.ICollectiontype IList = interface
interface ICollection
interface IEnumerablePublic Interface IList
Implements ICollection- 派生
- 属性
- 实现
示例
下面的示例演示 IList 接口的实现以创建具有固定大小的简单列表。The following example demonstrates the implementation of the IList interface to create a simple, fixed-size list.
using System;
using System.Collections;
class Program
{
static void Main()
{
var test = new SimpleList();
// Populate the List.
Console.WriteLine("Populate the List");
test.Add("one");
test.Add("two");
test.Add("three");
test.Add("four");
test.Add("five");
test.Add("six");
test.Add("seven");
test.Add("eight");
test.PrintContents();
Console.WriteLine();
// Remove elements from the list.
Console.WriteLine("Remove elements from the list");
test.Remove("six");
test.Remove("eight");
test.PrintContents();
Console.WriteLine();
// Add an element to the end of the list.
Console.WriteLine("Add an element to the end of the list");
test.Add("nine");
test.PrintContents();
Console.WriteLine();
// Insert an element into the middle of the list.
Console.WriteLine("Insert an element into the middle of the list");
test.Insert(4, "number");
test.PrintContents();
Console.WriteLine();
// Check for specific elements in the list.
Console.WriteLine("Check for specific elements in the list");
Console.WriteLine($"List contains \"three\": {test.Contains("three")}");
Console.WriteLine($"List contains \"ten\": {test.Contains("ten")}");
}
}
class SimpleList : IList
{
private object[] _contents = new object[8];
private int _count;
public SimpleList()
{
_count = 0;
}
// IList Members
public int Add(object value)
{
if (_count < _contents.Length)
{
_contents[_count] = value;
_count++;
return (_count - 1);
}
return -1;
}
public void Clear()
{
_count = 0;
}
public bool Contains(object value)
{
for (int i = 0; i < Count; i++)
{
if (_contents[i] == value)
{
return true;
}
}
return false;
}
public int IndexOf(object value)
{
for (int i = 0; i < Count; i++)
{
if (_contents[i] == value)
{
return i;
}
}
return -1;
}
public void Insert(int index, object value)
{
if ((_count + 1 <= _contents.Length) && (index < Count) && (index >= 0))
{
_count++;
for (int i = Count - 1; i > index; i--)
{
_contents[i] = _contents[i - 1];
}
_contents[index] = value;
}
}
public bool IsFixedSize
{
get
{
return true;
}
}
public bool IsReadOnly
{
get
{
return false;
}
}
public void Remove(object value)
{
RemoveAt(IndexOf(value));
}
public void RemoveAt(int index)
{
if ((index >= 0) && (index < Count))
{
for (int i = index; i < Count - 1; i++)
{
_contents[i] = _contents[i + 1];
}
_count--;
}
}
public object this[int index]
{
get
{
return _contents[index];
}
set
{
_contents[index] = value;
}
}
// ICollection members.
public void CopyTo(Array array, int index)
{
for (int i = 0; i < Count; i++)
{
array.SetValue(_contents[i], index++);
}
}
public int Count
{
get
{
return _count;
}
}
public bool IsSynchronized
{
get
{
return false;
}
}
// Return the current instance since the underlying store is not
// publicly available.
public object SyncRoot
{
get
{
return this;
}
}
// IEnumerable Members
public IEnumerator GetEnumerator()
{
// Refer to the IEnumerator documentation for an example of
// implementing an enumerator.
throw new NotImplementedException("The method or operation is not implemented.");
}
public void PrintContents()
{
Console.WriteLine($"List has a capacity of {_contents.Length} and currently has {_count} elements.");
Console.Write("List contents:");
for (int i = 0; i < Count; i++)
{
Console.Write($" {_contents[i]}");
}
Console.WriteLine();
}
}
// This code produces output similar to the following:
// Populate the List:
// List has a capacity of 8 and currently has 8 elements.
// List contents: one two three four five six seven eight
//
// Remove elements from the list:
// List has a capacity of 8 and currently has 6 elements.
// List contents: one two three four five seven
//
// Add an element to the end of the list:
// List has a capacity of 8 and currently has 7 elements.
// List contents: one two three four five seven nine
//
// Insert an element into the middle of the list:
// List has a capacity of 8 and currently has 8 elements.
// List contents: one two three four number five seven nine
//
// Check for specific elements in the list:
// List contains "three": True
// List contains "ten": False
Imports System.Collections
Public Class Program
Shared Sub Main()
Dim myList As New SimpleList()
' Populate the List.
Console.WriteLine("Populate the List")
myList.Add("one")
myList.Add("two")
myList.Add("three")
myList.Add("four")
myList.Add("five")
myList.Add("six")
myList.Add("seven")
myList.Add("eight")
myList.PrintContents()
Console.WriteLine()
' Remove elements from the list.
Console.WriteLine("Remove elements from the list")
myList.Remove("six")
myList.Remove("eight")
myList.PrintContents()
Console.WriteLine()
' Add an element to the end of the list.
Console.WriteLine("Add an element to the end of the list")
myList.Add("nine")
myList.PrintContents()
Console.WriteLine()
' Insert an element into the middle of the list.
Console.WriteLine("Insert an element into the middle of the list")
myList.Insert(4, "number")
myList.PrintContents()
Console.WriteLine()
' Check for specific elements in the list.
Console.WriteLine("Check for specific elements in the list")
Console.WriteLine($"List contains 'three': {myList.Contains("three")}")
Console.WriteLine($"List contains 'ten': {myList.Contains("ten")}")
End Sub
End Class
Public Class SimpleList
Implements IList
Private _contents(7) As Object
Private _count As Integer
Public Sub New()
_count = 0
End Sub
' IList members.
Public Function Add(ByVal value As Object) As Integer Implements IList.Add
If _count < _contents.Length Then
_contents(_count) = value
_count += 1
Return _count - 1
End If
Return -1
End Function
Public Sub Clear() Implements IList.Clear
_count = 0
End Sub
Public Function Contains(ByVal value As Object) As Boolean Implements IList.Contains
For i As Integer = 0 To Count - 1
If _contents(i) = value Then Return True
Next
Return False
End Function
Public Function IndexOf(ByVal value As Object) As Integer Implements IList.IndexOf
For i As Integer = 0 To Count - 1
If _contents(i) = value Then Return i
Next
Return -1
End Function
Public Sub Insert(ByVal index As Integer, ByVal value As Object) Implements IList.Insert
If _count + 1 <= _contents.Length AndAlso index < Count AndAlso index >= 0 Then
_count += 1
For i As Integer = Count - 1 To index Step -1
_contents(i) = _contents(i - 1)
Next
_contents(index) = value
End If
End Sub
Public ReadOnly Property IsFixedSize() As Boolean Implements IList.IsFixedSize
Get
Return True
End Get
End Property
Public ReadOnly Property IsReadOnly() As Boolean Implements IList.IsReadOnly
Get
Return False
End Get
End Property
Public Sub Remove(ByVal value As Object) Implements IList.Remove
RemoveAt(IndexOf(value))
End Sub
Public Sub RemoveAt(ByVal index As Integer) Implements IList.RemoveAt
if index >= 0 AndAlso index < Count Then
for i As Integer = index To Count - 2
_contents(i) = _contents(i + 1)
Next
_count -= 1
End If
End Sub
Public Property Item(ByVal index As Integer) As Object Implements IList.Item
Get
Return _contents(index)
End Get
Set(ByVal value As Object)
_contents(index) = value
End Set
End Property
' ICollection members.
Public Sub CopyTo(ByVal array As Array, ByVal index As Integer) Implements ICollection.CopyTo
For i As Integer = 0 To Count - 1
array.SetValue(_contents(i), index)
index += 1
Next
End Sub
Public ReadOnly Property Count() As Integer Implements ICollection.Count
Get
Return _count
End Get
End Property
Public ReadOnly Property IsSynchronized() As Boolean Implements ICollection.IsSynchronized
Get
Return False
End Get
End Property
' Return the current instance since the underlying store is not
' publicly available.
Public ReadOnly Property SyncRoot() As Object Implements ICollection.SyncRoot
Get
Return Me
End Get
End Property
' IEnumerable members.
Public Function GetEnumerator() As IEnumerator Implements IEnumerable.GetEnumerator
' Refer to the IEnumerator documentation for an example of
' implementing an enumerator.
Throw New NotImplementedException("The method or operation is not implemented.")
End Function
Public Sub PrintContents()
Console.WriteLine($"List has a capacity of {_contents.Length} and currently has {_count} elements.")
Console.Write("List contents:")
For i As Integer = 0 To Count - 1
Console.Write($" {_contents(i)}")
Next
Console.WriteLine()
End Sub
End Class
' This code produces output similar to the following:
' Populate the List:
' List has a capacity of 8 and currently has 8 elements.
' List contents: one two three four five six seven eight
'
' Remove elements from the list:
' List has a capacity of 8 and currently has 6 elements.
' List contents: one two three four five seven
'
' Add an element to the end of the list:
' List has a capacity of 8 and currently has 7 elements.
' List contents: one two three four five seven nine
'
' Insert an element into the middle of the list:
' List has a capacity of 8 and currently has 8 elements.
' List contents: one two three four number five seven nine
'
' Check for specific elements in the list:
' List contains "three": True
' List contains "ten": False
注解
IList 是 ICollection 接口的后代，是所有非泛型列表的基接口。IList is a descendant of the ICollection interface and is the base interface of all non-generic lists. IList 实现分为三个类别：只读、固定大小和可变大小。IList implementations fall into three categories: read-only, fixed-size, and variable-size. 不能修改只读 IList。A read-only IList cannot be modified. 固定大小的 IList 不允许添加或删除元素，但允许修改现有元素。A fixed-size IList does not allow the addition or removal of elements, but it allows the modification of existing elements. 可变大小 IList 允许添加、移除和修改元素。A variable-size IList allows the addition, removal, and modification of elements.
有关此接口的泛型版本，请参阅 System.Collections.Generic.IList<T>。For the generic version of this interface, see System.Collections.Generic.IList<T>.
属性
| Count |
获取 ICollection 中包含的元素数。Gets the number of elements contained in the ICollection. (继承自 ICollection) |
| IsFixedSize |
获取一个值，该值指示 IList 是否具有固定大小。Gets a value indicating whether the IList has a fixed size. |
| IsReadOnly |
获取一个值，用于指示 IList 是否为只读。Gets a value indicating whether the IList is read-only. |
| IsSynchronized |
获取一个值，该值指示是否同步对 ICollection 的访问（线程安全）。Gets a value indicating whether access to the ICollection is synchronized (thread safe). (继承自 ICollection) |
| Item[Int32] |
获取或设置指定索引处的元素。Gets or sets the element at the specified index. |
| SyncRoot |
获取可用于同步对 ICollection 的访问的对象。Gets an object that can be used to synchronize access to the ICollection. (继承自 ICollection) |
方法
| Add(Object) | |
| Clear() | |
| Contains(Object) |
确定 IList 是否包含特定值。Determines whether the IList contains a specific value. |
| CopyTo(Array, Int32) |
从特定的 ICollection 索引开始，将 Array 的元素复制到一个 Array 中。Copies the elements of the ICollection to an Array, starting at a particular Array index. (继承自 ICollection) |
| GetEnumerator() |
返回循环访问集合的枚举器。Returns an enumerator that iterates through a collection. (继承自 IEnumerable) |
| IndexOf(Object) |
确定 IList 中特定项的索引。Determines the index of a specific item in the IList. |
| Insert(Int32, Object) |
将项插入到 IList 中的指定索引处。Inserts an item to the IList at the specified index. |
| Remove(Object) |
从 IList 中删除特定对象的第一个匹配项。Removes the first occurrence of a specific object from the IList. |
| RemoveAt(Int32) |
移除位于指定索引处的 IList 项。Removes the IList item at the specified index. |
扩展方法
| Cast<TResult>(IEnumerable) |
将 IEnumerable 的元素强制转换为指定的类型。Casts the elements of an IEnumerable to the specified type. |
| OfType<TResult>(IEnumerable) |
根据指定类型筛选 IEnumerable 的元素。Filters the elements of an IEnumerable based on a specified type. |
| AsParallel(IEnumerable) |
启用查询的并行化。Enables parallelization of a query. |
| AsQueryable(IEnumerable) |
将 IEnumerable 转换为 IQueryable。Converts an IEnumerable to an IQueryable. |