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GC.Collect Method ()

Forces an immediate garbage collection of all generations.

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

Public Shared Sub Collect

public static void Collect ()
public static function Collect ()
Not applicable.

Use this method to try to reclaim all memory that is inaccessible.

All objects, regardless of how long they have been in memory, are considered for collection; however, objects that are referenced in managed code are not collected. Use this method to force the system to try to reclaim the maximum amount of available memory.

The following example demonstrates how to use the Collect method to perform a collection on all generations of memory. The code generates a number of unused objects, and then calls the Collect method to clean them from memory.

Imports System

Namespace GCCollect_Example
    Class MyGCCollectClass
        Private Const maxGarbage As Integer = 1000

        Shared Sub Main()
            'Put some objects in memory.
            Console.WriteLine("Memory used before collection: {0}", GC.GetTotalMemory(False))

            'Collect all generations of memory.
            Console.WriteLine("Memory used after full collection: {0}", GC.GetTotalMemory(True))
        End Sub

        Shared Sub MakeSomeGarbage()
            Dim vt As Version

            Dim i As Integer
            For i = 0 To maxGarbage - 1
                'Create objects and release them to fill up memory
                'with unused objects.
                vt = New Version()
            Next i
        End Sub
    End Class
End Namespace

package GCCollectExample ; 

import System.* ;

class MyGCCollectClass
    private static final int maxGarbage = 1000;

    public static void main(String[] args)
        // Put some objects in memory.
        Console.WriteLine("Memory used before collection: {0}", 

        // Collect all generations of memory.
        Console.WriteLine("Memory used after full collection: {0}", 
    } //main

    static void MakeSomeGarbage()
        Version vt;

        for (int i = 0; i < maxGarbage; i++) {
            // Create objects and release them to fill up memory
            // with unused objects.
            vt = new Version();
    } //MakeSomeGarbage
} //MyGCCollectClass

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

XNA Framework

Supported in: 1.0