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 Const GWL_STYLE = (-16)
Private Const WS_MAXIMIZEBOX = &H10000
Private Sub MDIForm_Load()
Dim lngStyle As Long
lngStyle = GetWindowLong(Me.hwnd, GWL_STYLE)
SetWindowLong Me.hwnd, GWL_STYLE, lngStyle Xor WS_MAXIMIZEBOX
End Sub
亲测过,可以实现你的效果