Classic VB - How can I Hide/Unhide the Form's "X" Button

[MartinLiss]

Credit for the Hide/Unhide code goes to crptcblade.

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 Declare Function DrawMenuBar Lib "user32" (ByVal hwnd  _
As Long) As Long
 
Private Const MF_BYCOMMAND = &H0&
Private Const SC_CLOSE = &HF060&
 
Public Sub SetXState(frm As Form, blnState As Boolean)
    Dim hMenu As Long
 
    hMenu = GetSystemMenu(frm.hwnd, blnState)
    Call RemoveMenu(hMenu, SC_CLOSE, MF_BYCOMMAND)
    Call DrawMenuBar(frm.hwnd)
 
End Sub

Example of Usage:

Private Sub Command1_Click()
    If opt(0).Value = True Then 
        SetXState Me, True   'enable the X button
    ElseIf opt(1).Value = True Then
        SetXState Me, False  'disable the X button
    End If
End Sub

You can however avoid all that and just do this

Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
    If UnloadMode = vbFormControlMenu Then
        cmdExit = True ' Change cmdExit to the name of your exit command button
                       ' and the code behind that button will be executed
    End If
End Sub