Disabled/Enabled the Max/Min button of a form at runtime.

Anybody know how to disabled/enabled the maximized/minimized button of a form at runtime?

You can use the SetWindowLong API, eg.

In a Module..

Code:

---

Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowPos Lib "user32" (ByVal hwnd As Long, ByVal hWndInsertAfter As Long, ByVal x As Long, ByVal y As Long, ByVal cx As Long, ByVal cy As Long, ByVal wFlags As Long) As Long

Private Const SWP_FRAMECHANGED = &H20
Private Const SWP_NOACTIVATE = &H10
Private Const SWP_NOMOVE = &H2
Private Const SWP_NOSIZE = &H1
Private Const WS_MAXIMIZEBOX = &H10000
Private Const WS_MINIMIZEBOX = &H20000
Private Const GWL_STYLE = (-16)

Public Sub MinBox(ByRef oForm As Form, Optional ByVal bEnabled As Boolean = True)
    Dim lStyle As Long
    lStyle = GetWindowLong(oForm.hwnd, GWL_STYLE)
    If bEnabled Then
        lStyle = lStyle Or WS_MINIMIZEBOX
    Else
        lStyle = lStyle Xor WS_MINIMIZEBOX
    End If
    Call SetWindowLong(oForm.hwnd, GWL_STYLE, lStyle)
    Call SetWindowPos(oForm.hwnd, 0, 0, 0, 0, 0, SWP_FRAMECHANGED Or SWP_NOMOVE Or SWP_NOSIZE Or SWP_NOACTIVATE)
End Sub

Public Sub MaxBox(ByRef oForm As Form, Optional ByVal bEnabled As Boolean = True)
    Dim lStyle As Long
    lStyle = GetWindowLong(oForm.hwnd, GWL_STYLE)
    If bEnabled Then
        lStyle = lStyle Or WS_MAXIMIZEBOX
    Else
        lStyle = lStyle Xor WS_MAXIMIZEBOX
    End If
    Call SetWindowLong(oForm.hwnd, GWL_STYLE, lStyle)
    Call SetWindowPos(oForm.hwnd, 0, 0, 0, 0, 0, SWP_FRAMECHANGED Or SWP_NOMOVE Or SWP_NOSIZE Or SWP_NOACTIVATE)
End Sub

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In the Form, (With 2 Command Buttons)..

Code:

---

Private Sub Command1_Click()
    Static bEnabled As Boolean
    bEnabled = Not bEnabled
    MinBox Me, bEnabled
End Sub

Private Sub Command2_Click()
    Static bEnabled As Boolean
    bEnabled = Not bEnabled
    MaxBox Me, bEnabled
End Sub

---

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Aaron Young
Analyst Programmer
[email protected]
[email protected]

HUH? Aarron isn't that the hard way?
Maybe I misunderstood but...

Go to properties of the form...
There should be a MaxButton and a MinButton.

If I'm wrong or I misunderstood email me...

Clefus you can't change it at run time just like that.

------------------
Visual Basic Programmer (at least I want to be one)
------------------
PolComSoft
You will hear a lot about it.

[This message has been edited by QWERTY (edited 11-12-1999).]