NameObjectCollectionBase.BaseAdd(String, Object) 方法

定义

命名空间:

System.Collections.Specialized

程序集:

System.Collections.Specialized.dll

Source:

NameObjectCollectionBase.cs

将具有指定键和值的项添加到 NameObjectCollectionBase 实例中。

protected:
 void BaseAdd(System::String ^ name, System::Object ^ value);

protected void BaseAdd (string? name, object? value);

member this.BaseAdd : string * obj -> unit

Protected Sub BaseAdd (name As String, value As Object)

参数

name

String

要添加的项的 String 键。 键可以是 null。

value

Object

要添加的项的 Object 值。 该值可以为 null。

例外

NotSupportedException

该集合是只读的。

示例

下面的代码示例使用 BaseAdd 通过 中的 IDictionary元素创建新的 NameObjectCollectionBase 。

#using <system.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
public ref class MyCollection: public NameObjectCollectionBase
{
private:
   DictionaryEntry _de;

public:

   property DictionaryEntry Item [ int ]
   {
      // Gets a key-and-value pair (DictionaryEntry) using an index.
      DictionaryEntry get( int index )
      {
         _de.Key = this->BaseGetKey( index );
         _de.Value = this->BaseGet( index );
         return (_de);
      }
   }

   // Adds elements from an IDictionary* into the new collection.
   MyCollection( IDictionary^ d )
   {
      IEnumerator^ myEnum = d->GetEnumerator();
      while ( myEnum->MoveNext() )
      {
         DictionaryEntry^ de = safe_cast<DictionaryEntry^>(myEnum->Current);
         this->BaseAdd( safe_cast<String^>(de->Key), de->Value );
      }
   }
};

int main()
{
   // Creates and initializes a new MyCollection instance.
   IDictionary^ d = gcnew ListDictionary;
   d->Add( "red", "apple" );
   d->Add( "yellow", "banana" );
   d->Add( "green", "pear" );
   MyCollection^ myCol = gcnew MyCollection( d );

   // Displays the keys and values of the MyCollection instance.
   for ( int i = 0; i < myCol->Count; i++ )
   {
      Console::WriteLine( "[{0}] : {1}, {2}", i, myCol->Item[ i ].Key, myCol->Item[ i ].Value );
   }
}

/*
This code produces the following output.

[0] : red, apple
[1] : yellow, banana
[2] : green, pear

*/

using System;
using System.Collections;
using System.Collections.Specialized;

public class MyCollection : NameObjectCollectionBase  {

   private DictionaryEntry _de = new DictionaryEntry();

   // Gets a key-and-value pair (DictionaryEntry) using an index.
   public DictionaryEntry this[ int index ]  {
      get  {
         _de.Key = this.BaseGetKey( index );
         _de.Value = this.BaseGet( index );
         return( _de );
      }
   }

   // Adds elements from an IDictionary into the new collection.
   public MyCollection( IDictionary d )  {
      foreach ( DictionaryEntry de in d )  {
         this.BaseAdd( (String) de.Key, de.Value );
      }
   }
}

public class SamplesNameObjectCollectionBase  {

   public static void Main()  {

      // Creates and initializes a new MyCollection instance.
      IDictionary d = new ListDictionary();
      d.Add( "red", "apple" );
      d.Add( "yellow", "banana" );
      d.Add( "green", "pear" );
      MyCollection myCol = new MyCollection( d );

      // Displays the keys and values of the MyCollection instance.
      for ( int i = 0; i < myCol.Count; i++ )  {
         Console.WriteLine( "[{0}] : {1}, {2}", i, myCol[i].Key, myCol[i].Value );
      }
   }
}


/*
This code produces the following output.

[0] : red, apple
[1] : yellow, banana
[2] : green, pear

*/

Imports System.Collections
Imports System.Collections.Specialized

Public Class MyCollection
   Inherits NameObjectCollectionBase

   Private _de As New DictionaryEntry()

   ' Gets a key-and-value pair (DictionaryEntry) using an index.
   Default Public ReadOnly Property Item(index As Integer) As DictionaryEntry
      Get
         _de.Key = Me.BaseGetKey(index)
         _de.Value = Me.BaseGet(index)
         Return _de
      End Get
   End Property

   ' Adds elements from an IDictionary into the new collection.
   Public Sub New(d As IDictionary)
      Dim de As DictionaryEntry
      For Each de In  d
         Me.BaseAdd(CType(de.Key, [String]), de.Value)
      Next de
   End Sub

End Class


Public Class SamplesNameObjectCollectionBase   

   Public Shared Sub Main()

      ' Creates and initializes a new MyCollection instance.
      Dim d = New ListDictionary()
      d.Add("red", "apple")
      d.Add("yellow", "banana")
      d.Add("green", "pear")
      Dim myCol As New MyCollection(d)

      ' Displays the keys and values of the MyCollection instance.
      Dim i As Integer
      For i = 0 To myCol.Count - 1
         Console.WriteLine("[{0}] : {1}, {2}", i, myCol(i).Key, myCol(i).Value)
      Next i

   End Sub

End Class


'This code produces the following output.
'
'[0] : red, apple
'[1] : yellow, banana
'[2] : green, pear

注解

如果 Count 已等于 容量，则通过自动重新分配内部数组来增加 的 NameObjectCollectionBase 容量，并在添加新元素之前将现有元素复制到新数组。

如果 Count 小于容量，则此方法为 O (1) 操作。 如果需要增加容量以适应新元素，此方法将成为 O (n) 操作，其中 n 为 Count。