Visual Basic > Windows and Controls

Disable a Windows Close Button

Disable a Windows Close Button

This sample will show you how to disable the little 'X' close button found on the upper right of every window.  To do this what we will do is use a couple of API calls to remove the Close menu item from the windows system menu.  Doing this will disable the close button.  When you try out this sample, you may want to have an alternate way to close your window.

Insert this code into a .bas module

Option Explicit

Public Declare Function GetSystemMenu Lib "user32" _
    (ByVal hwnd As Long, _
     ByVal bRevert As Long) As Long

Public Declare Function RemoveMenu Lib "user32" _
    (ByVal hMenu As Long, _
     ByVal nPosition As Long, _
     ByVal wFlags As Long) As Long

Public Const MF_BYPOSITION = &H400&


Public Sub DisableCloseWindowButton(frm As Form)

    Dim hSysMenu As Long

    'Get the handle to this windows
    'system menu
    hSysMenu = GetSystemMenu(frm.hwnd, 0)

    'Remove the Close menu item
    'This will also disable the close button
    RemoveMenu hSysMenu, 6, MF_BYPOSITION

    'Lastly, we remove the seperator bar
    RemoveMenu hSysMenu, 5, MF_BYPOSITION

End Sub
'--end code block
Now call the DisableCloseWindowButton from your forms load event.

Private Sub Form_Load()
    DisableCloseWindowButton Me
End Sub
'--end code block