Hashtable.CopyTo(Array, Int32) 方法

定义

命名空间:

System.Collections

程序集:

System.Runtime.dll

Source:

Hashtable.cs

将 Hashtable 元素复制到一维 Array 实例中的指定索引位置。

public:
 virtual void CopyTo(Array ^ array, int arrayIndex);

public virtual void CopyTo (Array array, int arrayIndex);

abstract member CopyTo : Array * int -> unit
override this.CopyTo : Array * int -> unit

Public Overridable Sub CopyTo (array As Array, arrayIndex As Integer)

参数

array

Array

一维 Array，它是从 DictionaryEntry 复制的 Hashtable 对象的目标位置。 Array 必须具有从零开始的索引。

arrayIndex

Int32

array 中从零开始的索引，从此处开始复制。

实现

CopyTo(Array, Int32)

例外

ArgumentNullException

array 为 null。

ArgumentOutOfRangeException

arrayIndex 小于零。

ArgumentException

array 是多维的。

或

源 Hashtable 中的元素个数大于从 arrayIndex 到目标 array 末尾之间的可用空间。

InvalidCastException

无法自动将源 Hashtable 的类型转换为目标 array 的类型。

示例

以下示例演示如何将 中的键列表或值 Hashtable 列表复制到一维 Array中。

using namespace System;
using namespace System::Collections;
void PrintValues( array<String^>^myArr, char mySeparator );
int main()
{
   
   // Creates and initializes the source Hashtable.
   Hashtable^ mySourceHT = gcnew Hashtable;
   mySourceHT->Add( "A", "valueA" );
   mySourceHT->Add( "B", "valueB" );
   
   // Creates and initializes the one-dimensional target Array.
   array<String^>^myTargetArray = gcnew array<String^>(15);
   myTargetArray[ 0 ] = "The";
   myTargetArray[ 1 ] = "quick";
   myTargetArray[ 2 ] = "brown";
   myTargetArray[ 3 ] = "fox";
   myTargetArray[ 4 ] = "jumps";
   myTargetArray[ 5 ] = "over";
   myTargetArray[ 6 ] = "the";
   myTargetArray[ 7 ] = "lazy";
   myTargetArray[ 8 ] = "dog";
   
   // Displays the values of the target Array.
   Console::WriteLine( "The target Array contains the following before:" );
   PrintValues( myTargetArray, ' ' );
   
   // Copies the keys in the source Hashtable to the target Hashtable, starting at index 6.
   Console::WriteLine( "After copying the keys, starting at index 6:" );
   mySourceHT->Keys->CopyTo( myTargetArray, 6 );
   
   // Displays the values of the target Array.
   PrintValues( myTargetArray, ' ' );
   
   // Copies the values in the source Hashtable to the target Hashtable, starting at index 6.
   Console::WriteLine( "After copying the values, starting at index 6:" );
   mySourceHT->Values->CopyTo( myTargetArray, 6 );
   
   // Displays the values of the target Array.
   PrintValues( myTargetArray, ' ' );
}

void PrintValues( array<String^>^myArr, char mySeparator )
{
   for ( int i = 0; i < myArr->Length; i++ )
      Console::Write( "{0}{1}", mySeparator, myArr[ i ] );
   Console::WriteLine();
}

/* 
 This code produces the following output.
 
 The target Array contains the following before:
  The quick brown fox jumps over the lazy dog
 After copying the keys, starting at index 6:
  The quick brown fox jumps over B A dog
 After copying the values, starting at index 6:
  The quick brown fox jumps over valueB valueA dog

 */

using System;
using System.Collections;
public class SamplesHashtable
{

   public static void Main()
   {
      // Creates and initializes the source Hashtable.
      var mySourceHT = new Hashtable();
      mySourceHT.Add("A", "valueA");
      mySourceHT.Add("B", "valueB");

      // Creates and initializes the one-dimensional target Array.
      var myTargetArray = new String[15];
      myTargetArray[0] = "The";
      myTargetArray[1] = "quick";
      myTargetArray[2] = "brown";
      myTargetArray[3] = "fox";
      myTargetArray[4] = "jumps";
      myTargetArray[5] = "over";
      myTargetArray[6] = "the";
      myTargetArray[7] = "lazy";
      myTargetArray[8] = "dog";

      // Displays the values of the target Array.
      Console.WriteLine("The target Array contains the following before:");
      PrintValues(myTargetArray, ' ');

      // Copies the keys in the source Hashtable to the target Hashtable, starting at index 6.
      Console.WriteLine("After copying the keys, starting at index 6:");
      mySourceHT.Keys.CopyTo(myTargetArray, 6);

      // Displays the values of the target Array.
      PrintValues(myTargetArray, ' ');

      // Copies the values in the source Hashtable to the target Hashtable, starting at index 6.
      Console.WriteLine("After copying the values, starting at index 6:");
      mySourceHT.Values.CopyTo(myTargetArray, 6);

      // Displays the values of the target Array.
      PrintValues(myTargetArray, ' ');
   }

   public static void PrintValues(String[] myArr, char mySeparator)
   {
      for (int i = 0; i < myArr.Length; i++)
         Console.Write($"{mySeparator}{myArr[i]}");
      Console.WriteLine();
   }
}
/*
This code produces the following output.

The target Array contains the following before:
 The quick brown fox jumps over the lazy dog
After copying the keys, starting at index 6:
 The quick brown fox jumps over B A dog
After copying the values, starting at index 6:
 The quick brown fox jumps over valueB valueA dog

*/

Imports System.Collections

Public Class SamplesHashtable

    Public Shared Sub Main()

        ' Creates and initializes the source Hashtable.
        Dim mySourceHT As New Hashtable()
        mySourceHT.Add("A", "valueA")
        mySourceHT.Add("B", "valueB")

        ' Creates and initializes the one-dimensional target Array.
        Dim myTargetArray(14) As String
        myTargetArray(0) = "The"
        myTargetArray(1) = "quick"
        myTargetArray(2) = "brown"
        myTargetArray(3) = "fox"
        myTargetArray(4) = "jumps"
        myTargetArray(5) = "over"
        myTargetArray(6) = "the"
        myTargetArray(7) = "lazy"
        myTargetArray(8) = "dog"

        ' Displays the values of the target Array.
        Console.WriteLine("The target Array contains the following before:")
        PrintValues(myTargetArray, " "c)

        ' Copies the keys in the source Hashtable to the target Hashtable, starting at index 6.
        Console.WriteLine("After copying the keys, starting at index 6:")
        mySourceHT.Keys.CopyTo(myTargetArray, 6)

        ' Displays the values of the target Array.
        PrintValues(myTargetArray, " "c)

        ' Copies the values in the source Hashtable to the target Hashtable, starting at index 6.
        Console.WriteLine("After copying the values, starting at index 6:")
        mySourceHT.Values.CopyTo(myTargetArray, 6)

        ' Displays the values of the target Array.
        PrintValues(myTargetArray, " "c)

    End Sub

    Public Shared Sub PrintValues(myArr As String(), mySeparator As Char)
        For i As Integer = 0 To myArr.Length - 1
            Console.Write($"{mySeparator}{myArr(i)}")
        Next i
        Console.WriteLine()
    End Sub

End Class


' This code produces the following output.
' 
' The target Array contains the following before:
'  The quick brown fox jumps over the lazy dog
' After copying the keys, starting at index 6:
'  The quick brown fox jumps over A B dog
' After copying the values, starting at index 6:
'  The quick brown fox jumps over valueA valueB dog

注解

元素将按照枚举器循环访问 的相同顺序复制到 Array 。Hashtable

若要仅复制 中的 Hashtable密钥，请使用 Hashtable.Keys.CopyTo。

若要仅复制 中的 Hashtable值，请使用 Hashtable.Values.CopyTo。

此方法是一个 O(n) 操作，其中 n 是 Count。

另请参阅

• Array
• DictionaryEntry
• GetEnumerator()