ArrayList.TrimToSize Method
Sets the capacity to the actual number of elements in the ArrayList.
Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)
| Exception | Condition |
|---|---|
| NotSupportedException | The ArrayList is read-only. -or- The ArrayList has a fixed size. |
This method can be used to minimize a collection's memory overhead if no new elements will be added to the collection.
To reset a ArrayList to its initial state, call the Clear method before calling TrimToSize. Trimming an empty ArrayList sets the capacity of the ArrayList to the default capacity.
This method is an O(n) operation, where n is Count.
The following code example shows how to trim the unused portions of the ArrayList and how to clear the values of the 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" ); // Displays the count, capacity and values of the ArrayList. Console.WriteLine( "Initially," ); Console.WriteLine( " Count : {0}", myAL.Count ); Console.WriteLine( " Capacity : {0}", myAL.Capacity ); Console.Write( " Values:" ); PrintValues( myAL ); // Trim the ArrayList. myAL.TrimToSize(); // Displays the count, capacity and values of the ArrayList. Console.WriteLine( "After TrimToSize," ); Console.WriteLine( " Count : {0}", myAL.Count ); Console.WriteLine( " Capacity : {0}", myAL.Capacity ); Console.Write( " Values:" ); PrintValues( myAL ); // Clear the ArrayList. myAL.Clear(); // Displays the count, capacity and values of the ArrayList. Console.WriteLine( "After Clear," ); Console.WriteLine( " Count : {0}", myAL.Count ); Console.WriteLine( " Capacity : {0}", myAL.Capacity ); Console.Write( " Values:" ); PrintValues( myAL ); // Trim the ArrayList again. myAL.TrimToSize(); // Displays the count, capacity and values of the ArrayList. Console.WriteLine( "After the second TrimToSize," ); Console.WriteLine( " Count : {0}", myAL.Count ); Console.WriteLine( " Capacity : {0}", myAL.Capacity ); Console.Write( " Values:" ); PrintValues( myAL ); } public static void PrintValues( IEnumerable myList ) { foreach ( Object obj in myList ) Console.Write( " {0}", obj ); Console.WriteLine(); } } /* This code produces the following output. Initially, Count : 5 Capacity : 16 Values: The quick brown fox jumped After TrimToSize, Count : 5 Capacity : 5 Values: The quick brown fox jumped After Clear, Count : 0 Capacity : 5 Values: After the second TrimToSize, Count : 0 Capacity : 16 Values: */
Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
