ConditionalWeakTable<TKey,TValue>.Add(TKey, TValue) メソッド

定義

名前空間:

System.Runtime.CompilerServices

アセンブリ:

System.Runtime.dll

ソース:

ConditionalWeakTable.cs

テーブルにキーを追加します。

public:
 void Add(TKey key, TValue value);

public void Add (TKey key, TValue value);

member this.Add : 'Key * 'Value -> unit

Public Sub Add (key As TKey, value As TValue)

パラメーター

key

TKey

追加するキー。 key は、プロパティのアタッチ先となるオブジェクトを表します。

value

TValue

キーのプロパティ値。

例外

ArgumentNullException

key が nullです。

ArgumentException

key が既に存在します。

例

次の例では、 MainClass クラスと、 インスタンスに関する情報を MainInfo 提供する クラスを MainClass 定義します。 次に、 メソッドを Add 呼び出して、 MainClass オブジェクトとそのアタッチされた MainInfo オブジェクトをテーブルに ConditionalWeakTable<TKey,TValue> 追加します。 この例では、 メソッドと GetValue メソッドのGetOrCreateValue呼び出しを示し、キーと値のペアをテーブルに追加し、 メソッドに対してTryGetValue既存のキーの値を取得します。

using System;
using System.Reflection;
using System.Runtime.CompilerServices;

public class Example
{
   string Name; 
   
   public Example(string name)
   {
      this.Name = name;
   }
   
   public override string ToString()
   {
      return this.Name;
   }
}

// Define a class to contain information about each Example instance.
public class ExampleInfo
{
   public string Name;
   public int Methods;
   public int Properties;
   
   public override string ToString()
   {
      return String.Format("{0}: {1} Methods, {2} Properties", 
                           this.Name, this.Methods, this.Properties);
   }
}

public class ExampleTest
{
   private static BindingFlags flags = BindingFlags.Public | BindingFlags.Instance;

   public static void Main()
   {
      Example ex1 = new Example("ex1");
      Example ex2 = new Example("ex2");
      Example ex3 = new Example("ex3");
      
      ExampleInfo exInfo1 = new ExampleInfo(); 
      exInfo1.Name = ex1.ToString();
      exInfo1.Methods = ex1.GetType().GetMethods(flags).Length;
      exInfo1.Properties = ex1.GetType().GetProperties(flags).Length;
      
      ExampleInfo exInfo3 = new ExampleInfo(); 
      exInfo3.Name = ex3.ToString();
      exInfo3.Methods = ex3.GetType().GetMethods(flags).Length;
      exInfo3.Properties = ex3.GetType().GetProperties(flags).Length;

      var attached = new ConditionalWeakTable<Example, ExampleInfo>();
      ExampleInfo value = null;

      // Attach a property to ex1 using the Add method, then retrieve it.
      attached.Add(ex1, exInfo1);
      if (attached.TryGetValue(ex1, out value))
         Console.WriteLine("{0}, {1}", ex1, value);
      else
         Console.WriteLine("{0} does not have an attached property.", ex1);

      // Attempt to retrieve the value attached to ex2.
      value = attached.GetValue(ex2, ExampleTest.CreateAttachedValue);      
      if (attached.TryGetValue(ex2, out value))
         Console.WriteLine("{0}, {1}", ex2, value);
      else 
         Console.WriteLine("{0} does not have an attached property.", ex2);
      
      // Attempt to retrieve the value attached to ex3.
      value = attached.GetOrCreateValue(ex3);
      Console.WriteLine("{0}, {1}", ex3, value);
   }

   public static ExampleInfo CreateAttachedValue(Example ex)
   {
      ExampleInfo info = new ExampleInfo();
      info.Name = ex.ToString();
      info.Methods = ex.GetType().GetMethods(flags).Length;
      info.Properties = ex.GetType().GetProperties(flags).Length;
      return info;
   }
}
// The example displays the following output:
//       ex1, ex1: 4 Methods, 0 Properties
//       ex2, ex2: 4 Methods, 0 Properties
//       ex3, : 0 Methods, 0 Properties

Imports System.Reflection
Imports System.Runtime.CompilerServices

Public Class Example
   Public Name As String
   
   Public Sub New(name As String)
      Me.Name = name
   End Sub
   
   Public Overrides Function ToString() As String
      Return Me.Name
   End Function
End Class

' Define a class to contain information about each Example instance.
Public Class ExampleInfo
   Public Name As String
   Public Methods As Integer
   Public Properties As Integer
   
   Public Overrides Function ToString() As String
      Return String.Format("{0}: {1} Methods, {2} Properties", _
                           Me.Name, Me.Methods, Me.Properties)
   End Function
End Class

Module TestExample

   Private flags As BindingFlags = BindingFlags.Public Or BindingFlags.Instance

   Public Sub Main()
      Dim ex1 As New Example("ex1")
      Dim ex2 As New Example("ex2")
      Dim ex3 As New Example("ex3")
      
      Dim exInfo1 As New ExampleInfo() 
      exInfo1.Name = ex1.ToString()
      exInfo1.Methods = ex1.GetType().GetMethods(flags).Count
      exInfo1.Properties = ex1.GetType().GetProperties(flags).Count
      
      Dim exInfo3 As New ExampleInfo() 
      exInfo3.Name = ex3.ToString()
      exInfo3.Methods = ex3.GetType().GetMethods(flags).Count
      exInfo3.Properties = ex3.GetType().GetProperties(flags).Count

      Dim attached As New ConditionalWeakTable(Of Example, ExampleInfo)
      Dim value As ExampleInfo = Nothing

      ' Attach a property to ex1 using the Add method, then retrieve it.
      attached.Add(ex1, exInfo1)
      If attached.TryGetValue(ex1, value) Then
         Console.WriteLine("{0}, {1}", ex1, value)
      Else
         Console.WriteLine("{0} does not have an attached property.", ex1)
      End If

      ' Attempt to retrieve the value attached to ex2.
      value = attached.GetValue(ex2, AddressOf TestExample.CreateAttachedValue)      
      If attached.TryGetValue(ex2, value) Then
         Console.WriteLine("{0}, {1}", ex2, value)
      Else 
         Console.WriteLine("{0} does not have an attached property.", ex2)
      End If
      
      ' Atttempt to retrieve the value attached to ex3.
      value = attached.GetOrCreateValue(ex3)
      Console.WriteLine("{0}, {1}", ex3, value)
   End Sub
   
   Public Function CreateAttachedValue(ex As Example) As ExampleInfo
      Dim info As New ExampleInfo()
      info.Name = ex.ToString()
      info.Methods = ex.GetType().GetMethods(flags).Count
      info.Properties = ex.GetType().GetProperties(flags).Count
      Return info
   End Function
End Module
' The example displays the following output:
'       ex1, ex1: 4 Methods, 0 Properties
'       ex2, ex2: 4 Methods, 0 Properties
'       ex3, : 0 Methods, 0 Properties

注釈

オブジェクト内のすべてのキーは一 ConditionalWeakTable<TKey,TValue> 意である必要があります。 キーが同じオブジェクトを参照している場合は一意ではありません (つまり、メソッドに引数として渡すと が Object.ReferenceEquals 返されます true)。

追加操作中にキーがガベージ コレクションされた場合、既存のキーと値のペアが削除され、例外がスローされずに新しいキーと値のペアが追加されます。

こちらもご覧ください

• GetOrCreateValue(TKey)