Hashtable.CopyTo(Array, Int32) Method

Definition

Namespace:

System.Collections

Assemblies:

netstandard.dll, System.Runtime.dll

Source:

Hashtable.cs

Copies the Hashtable elements to a one-dimensional Array instance at the specified index.

C#

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

Parameters

array

Array

The one-dimensional Array that is the destination of the DictionaryEntry objects copied from Hashtable. The Array must have zero-based indexing.

arrayIndex

Int32

The zero-based index in array at which copying begins.

Implements

CopyTo(Array, Int32)

Exceptions

ArgumentNullException

array is null.

ArgumentOutOfRangeException

arrayIndex is less than zero.

ArgumentException

array is multidimensional.

-or-

The number of elements in the source Hashtable is greater than the available space from arrayIndex to the end of the destination array.

InvalidCastException

The type of the source Hashtable cannot be cast automatically to the type of the destination array.

Examples

The following example shows how to copy the list of keys or the list of values in a Hashtable into a one-dimensional Array.

C#

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

*/

Remarks

The elements are copied to the Array in the same order in which the enumerator iterates through the Hashtable.

To copy only the keys in the Hashtable, use Hashtable.Keys.CopyTo.

To copy only the values in the Hashtable, use Hashtable.Values.CopyTo.

This method is an O(n) operation, where n is Count.

Applies to

See also

• Array
• DictionaryEntry
• GetEnumerator()