Knowledge Base

FIX: A gradual memory leak occurs in a WinForm application when you create, modify, or remove a MenuItem property for an MDI form in the .NET Framework 1.1

Article ID: 873429

Article Last Modified on 4/7/2006

APPLIES TO

Microsoft .NET Framework 1.1

SYMPTOMS

When you create, modify, or remove a MenuItem property for a Multiple Document Interface (MDI) form in Microsoft .NET Framework 1.1 Service Pack 1 (SP1), a GDI resource leak occurs, and there is gradual increase in the application memory usage. This problem occurs when you create a WinForm application that uses an MDI form.

RESOLUTION

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Microsoft .NET Framework 1.1 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Date         Time   Version            Size    File name
---------------------------------------------------------------------------
23-Jul-2004  15:36  1.1.4322.1064   1,703,936  System.design.dll
23-Jul-2004  15:29  1.1.4322.1064     466,944  System.drawing.dll
23-Jul-2004  15:36  1.1.4322.1064   2,043,904  System.windows.forms.dll

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

Steps to reproduce the problem

Create a Visual Basic .NET MDI Form by using the following code.

Private Sub frmStart_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load

Menu = MenuMainSetup()


End Sub




Public Function MenuMainSetup() As MainMenu

' Set up main menu with 1 item (Member) and two subitems (Open and Close Member)




Dim mnuMain As New MainMenu




Dim mitAdd As New MenuItem("Member")


mitAdd.MergeType = MenuMerge.MergeItems


mitAdd.MergeOrder = 1


Dim i As Integer = mnuMain.MenuItems.Add(mitAdd)





mitAdd = New MenuItem("Open", New EventHandler(AddressOf zOpenChild))


mitAdd.MergeType = MenuMerge.MergeItems

mitAdd.MergeOrder = 1


mnuMain.MenuItems(i).MenuItems.Add(mitAdd)



mitAdd = New MenuItem("Close Member")


mitAdd.MergeType = MenuMerge.MergeItems


mitAdd.Visible = False


mitAdd.MergeOrder = 2


mnuMain.MenuItems(i).MenuItems.Add(mitAdd)




mitAdd = New MenuItem("Test GC", New EventHandler(AddressOf Test))


mitAdd.MergeType = MenuMerge.MergeItems


mitAdd.MergeOrder = 3


mnuMain.MenuItems(i).MenuItems.Add(mitAdd)





Return mnuMain


End Function




Public Function MenuSubSetup() As MainMenu


' Set up additional History menu item to go in Member menu


Dim mnuMain As New MainMenu


Dim mitAdd As New MenuItem("Member")


mitAdd.MergeType = MenuMerge.MergeItems


mitAdd.MergeOrder = 1


Dim i As Integer = mnuMain.MenuItems.Add(mitAdd)





mitAdd = New MenuItem("History")


mitAdd.MergeType = MenuMerge.MergeItems


mitAdd.MergeOrder = 4


mnuMain.MenuItems(i).MenuItems.Add(mitAdd)


mitAdd = Nothing


Return mnuMain


End Function




Private Sub zOpenChild(ByVal sender As System.Object, ByVal e As System.EventArgs)


' Open our only child


Dim f As New frmMemLeak



f.MdiParent = Me


f.Show()


End Sub




Private Sub Test(ByVal sender As System.Object, ByVal e As System.EventArgs)

GC.Collect()


GC.WaitForPendingFinalizers()


End Sub

Create a Windows Form by using the following code.

Region " Windows Form Designer generated code "



Public Class frmMemLeak : Inherits System.Windows.Forms.Form





#Region " Windows Form Designer generated code "





Public Sub New()


MyBase.New()





'This call is required by the Windows Form Designer.


InitializeComponent()





'Add any initialization after the InitializeComponent() call



End Sub



'Form overrides dispose to clean up the component list.


Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)


If disposing Then


If Not (components Is Nothing) Then


components.Dispose()


End If
End If


MyBase.Dispose(disposing)


End Sub



'Required by the Windows Form Designer


Private components As System.ComponentModel.IContainer





'NOTE: The following procedure is required by the Windows Form Designer


'It can be modified using the Windows Form Designer. 


'Do not modify it using the code editor.


Private WithEvents cmdClose As System.Windows.Forms.Button


<System.Diagnostics.DebuggerStepThrough()> 



Private Sub InitializeComponent()


Me.cmdClose = New System.Windows.Forms.Button


Me.SuspendLayout()


'


'cmdClose


'

Me.cmdClose.Location = New System.Drawing.Point(16, 16)


Me.cmdClose.Name = "cmdClose"


Me.cmdClose.TabIndex = 5


Me.cmdClose.Text = "Close"


'


'frmMemLeak


'


Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)


Me.ClientSize = New System.Drawing.Size(104, 61)


Me.Controls.Add(Me.cmdClose)


Me.Name = "frmMemLeak"


Me.Text = "Leak"


Me.ResumeLayout(False)

End Sub





#End Region




Private Sub frmMemLeak_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load


' Disable the Close Member menu item




MdiParent.Menu.MenuItems(0).MenuItems(1).Enabled = False



End Sub





Private Sub frmMemLeak_Activated(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Activated


' Add the History menu item to the Member menu


Menu = CType(MdiParent, frmStart).MenuSubSetup





End Sub





Private Sub cmdClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdClose.Click



MdiParent.Menu.MenuItems(0).MenuItems(1).Enabled = True



Me.Close()



End Sub


End Class

Run the application.
In the application, click Member, and then click Open.
In the application, click Member, and then click Test GC.
Repeat steps 4 and 5 several times to create the leak.

For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbbug kbfix kbqfe kbhotfixserver KB873429

Microsoft KB Archive/873429

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