SortedDictionary<TKey,TValue>.IDictionary.Contains(Object) 方法

定义

命名空间:

System.Collections.Generic

程序集:

System.Collections.dll

程序集:

System.dll

程序集:

netstandard.dll

确定是否 IDictionary 包含带有指定键的元素。

 virtual bool System.Collections.IDictionary.Contains(System::Object ^ key) = System::Collections::IDictionary::Contains;

bool IDictionary.Contains (object key);

abstract member System.Collections.IDictionary.Contains : obj -> bool
override this.System.Collections.IDictionary.Contains : obj -> bool

Function Contains (key As Object) As Boolean Implements IDictionary.Contains

参数

key

Object

要在 IDictionary 中定位的键。

返回

Boolean

如果 true 包含具有键的元素，则为 IDictionary；否则为 false。

实现

Contains(Object)

例外

ArgumentNullException

key 上声明的默认值为 null。

示例

下面的代码示例演示如何将 IDictionary.Contains 接口的方法 System.Collections.IDictionary 与 a SortedDictionary<TKey,TValue>. 该示例演示了如果提供了错误的数据类型的键，该方法将 false 返回该方法。

代码示例是为 IDictionary.Add 该方法提供的大型示例的一部分，包括输出。

using System;
using System.Collections;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create a new sorted dictionary of strings, with string keys,
        // and access it using the IDictionary interface.
        //
        IDictionary openWith = new SortedDictionary<string, string>();

        // Add some elements to the dictionary. There are no
        // duplicate keys, but some of the values are duplicates.
        // IDictionary.Add throws an exception if incorrect types
        // are supplied for key or value.
        openWith.Add("txt", "notepad.exe");
        openWith.Add("bmp", "paint.exe");
        openWith.Add("dib", "paint.exe");
        openWith.Add("rtf", "wordpad.exe");

Imports System.Collections
Imports System.Collections.Generic

Public Class Example
    
    Public Shared Sub Main() 

        ' Create a new sorted dictionary of strings, with string keys,
        ' and access it using the IDictionary interface.
        '
        Dim openWith As IDictionary = _
            New SortedDictionary(Of String, String)
        
        ' Add some elements to the dictionary. There are no 
        ' duplicate keys, but some of the values are duplicates.
        ' IDictionary.Add throws an exception if incorrect types
        ' are supplied for key or value.
        openWith.Add("txt", "notepad.exe")
        openWith.Add("bmp", "paint.exe")
        openWith.Add("dib", "paint.exe")
        openWith.Add("rtf", "wordpad.exe")

// Contains can be used to test keys before inserting
// them.
if (!openWith.Contains("ht"))
{
    openWith.Add("ht", "hypertrm.exe");
    Console.WriteLine("Value added for key = \"ht\": {0}",
        openWith["ht"]);
}

// IDictionary.Contains returns false if the wrong data
// type is supplied.
Console.WriteLine("openWith.Contains(29.7) returns {0}",
    openWith.Contains(29.7));

' Contains can be used to test keys before inserting 
' them.
If Not openWith.Contains("ht") Then
    openWith.Add("ht", "hypertrm.exe")
    Console.WriteLine("Value added for key = ""ht"": {0}", _
        openWith("ht"))
End If

' IDictionary.Contains returns False if the wrong data 
' type is supplied.
Console.WriteLine("openWith.Contains(29.7) returns {0}", _
    openWith.Contains(29.7))

    }
}

    End Sub

End Class

注解

此方法返回false的类型是否key不可分配给键SortedDictionary<TKey,TValue>类型的TKey类型。

此方法是 O (日志n) 操作，其中n。Count