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ArrayList.IsFixedSize Property

Gets a value indicating whether the ArrayList has a fixed size.

Namespace:  System.Collections
Assembly:  mscorlib (in mscorlib.dll)

public virtual bool IsFixedSize { get; }

Property Value

Type: System.Boolean
true if the ArrayList has a fixed size; otherwise, false. The default is false.

Implements

IList.IsFixedSize

A collection with a fixed size does not allow the addition or removal of elements after the collection is created, but it allows the modification of existing elements.

A collection with a fixed size is simply a collection with a wrapper that prevents adding and removing elements; therefore, if changes are made to the underlying collection, including the addition or removal of elements, the fixed-size collection reflects those changes.

Retrieving the value of this property is an O(1) operation.

The following code example shows how to create a fixed-size wrapper around an ArrayList.

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

   public static void Main()  {

      // Creates and initializes a new ArrayList.
      ArrayList myAL = new ArrayList();
      myAL.Add( "The" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );
      myAL.Add( "jumped" );
      myAL.Add( "over" );
      myAL.Add( "the" );
      myAL.Add( "lazy" );
      myAL.Add( "dog" );

      // Create a fixed-size wrapper around the ArrayList.
      ArrayList myFixedSizeAL = ArrayList.FixedSize( myAL );

      // Display whether the ArrayLists have a fixed size or not.
      Console.WriteLine( "myAL {0}.", myAL.IsFixedSize ? "has a fixed size" : "does not have a fixed size" );
      Console.WriteLine( "myFixedSizeAL {0}.", myFixedSizeAL.IsFixedSize ? "has a fixed size" : "does not have a fixed size" );
      Console.WriteLine();

      // Display both ArrayLists.
      Console.WriteLine( "Initially," );
      Console.Write( "Standard  :" );
      PrintValues( myAL, ' ' );
      Console.Write( "Fixed size:" );
      PrintValues( myFixedSizeAL, ' ' );

      // Sort is allowed in the fixed-size ArrayList.
      myFixedSizeAL.Sort();

      // Display both ArrayLists.
      Console.WriteLine( "After Sort," );
      Console.Write( "Standard  :" );
      PrintValues( myAL, ' ' );
      Console.Write( "Fixed size:" );
      PrintValues( myFixedSizeAL, ' ' );

      // Reverse is allowed in the fixed-size ArrayList.
      myFixedSizeAL.Reverse();

      // Display both ArrayLists.
      Console.WriteLine( "After Reverse," );
      Console.Write( "Standard  :" );
      PrintValues( myAL, ' ' );
      Console.Write( "Fixed size:" );
      PrintValues( myFixedSizeAL, ' ' );

      // Add an element to the standard ArrayList.
      myAL.Add( "AddMe" );

      // Display both ArrayLists.
      Console.WriteLine( "After adding to the standard ArrayList," );
      Console.Write( "Standard  :" );
      PrintValues( myAL, ' ' );
      Console.Write( "Fixed size:" );
      PrintValues( myFixedSizeAL, ' ' );
      Console.WriteLine();

      // Adding or inserting elements to the fixed-size ArrayList throws an exception. 
      try  {
         myFixedSizeAL.Add( "AddMe2" );
      } catch ( Exception myException )  {
         Console.WriteLine("Exception: " + myException.ToString());
      }
      try  {
         myFixedSizeAL.Insert( 3, "InsertMe" );
      } catch ( Exception myException )  {
         Console.WriteLine("Exception: " + myException.ToString());
      }
   }

   public static void PrintValues( IEnumerable myList, char mySeparator )  {
      foreach ( Object obj in myList )
         Console.Write( "{0}{1}", mySeparator, obj );
      Console.WriteLine();
   }

}
/*
This code produces the following output.

myAL does not have a fixed size.
myFixedSizeAL has a fixed size.

Initially,
Standard  : The quick brown fox jumped over the lazy dog
Fixed size: The quick brown fox jumped over the lazy dog
After Sort,
Standard  : brown dog fox jumped lazy over quick the The
Fixed size: brown dog fox jumped lazy over quick the The
After Reverse,
Standard  : The the quick over lazy jumped fox dog brown
Fixed size: The the quick over lazy jumped fox dog brown
After adding to the standard ArrayList,
Standard  : The the quick over lazy jumped fox dog brown AddMe
Fixed size: The the quick over lazy jumped fox dog brown AddMe

Exception: System.NotSupportedException: Collection was of a fixed size.
   at System.Collections.FixedSizeArrayList.Add(Object obj)
   at SamplesArrayList.Main()
Exception: System.NotSupportedException: Collection was of a fixed size.
   at System.Collections.FixedSizeArrayList.Insert(Int32 index, Object obj)
   at SamplesArrayList.Main()

*/

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0
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