Disable ALT+F4 key in a form

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  13 years ago

  by dilinafonseka

  dilina fonseka

  , Sri Lanka

  Joined 13 years ago
  i want to disable ALT+F4 in a form that me can't close the page
  
  can anyone send me source code todo it in C#.net?????
  
  
  
  
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  13 years ago

  by rrvenki

  Raja Venkatesh Ramasamy

  Tamilnadu, India

  Joined 13 years ago

  Below code is for VB6.  You may upgrade the code to .NET too.

  Put the below function in a module level.

  Public Function RemoveXButton(frmWindow as Form)

  dim hMenu as Long

  dim nCount as Long

  hMenu=GetSystemMenu(frmWindow.Hwnd,0)

  nCount=GetMenuItemCount(hMenu)

  'Remove the last two menu items which are a seperator and Alt+F4

  Call RemoveMenu(hMenu ,nCount-1, MF_REMOVE OR MF_BYPOSITION)

  Call RemoveMenu(hMenu, nCount-1, MF_REMOVE OR MF_BYPOSITION)

  DrawMenuBar frmWindow.hWnd

  End Function

   

  'Declarations

  Public Declare Function GetSystemMenu Lib "User32" (byval hwnd as Long, byval bRevert as Long) as Long

  ...

  Public Const MF_BYPOSITION = &H400&

  Public Const MF_REMOVE = &H1000&

  Similar to GetSystemMenu, search over internet and get declarations for GetMenuItemCount, RemoveMenu and DrawMenuBar.

  Thanks and Good luck

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  13 years ago

  by jefftullin

  Jeff Tullin

  , United Kingdom

  Joined 13 years ago

  Perhaps an easier way is to just stop the form from closing.

  ALT-F4 is a request to close, rather than a force-close.

   

  Check out the .Closing Event of the form. It has a parameter which is read/write.

  The help says 'The Closing event occurs as the form is being closed.... If you cancel this event, the form remains opened. To cancel the closure of a form, set the Cancel property of the CancelEventArgs passed to your event handler to true.'

  If this means the form does not close when you want it to, try having a member property like    m_bYesIReallyMeanIt  which you can set and check...

   

   

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  13 years ago

  by dilinafonseka

  dilina fonseka

  , Sri Lanka

  Joined 13 years ago

  Thnx 4 ur help.......

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  12 years ago

  by Mohammad Rastkar

  Mohammad Rastkar

  Shiraz, Iran

  Joined 14 years ago

  OK, you're idea is good that we should express clearly, but some times you should search by yourself, for what you don't know and get some knowledge some where else.

  Anyway, about 'm_bYesIReallyMeanIt' : I think it's about this : when you cancel closing a form by setting 'Cancel' member of 'FormClosingEventArgs' parameter of the form's 'FormClosing' event, you may want [for example] when user press 'Alt + F4' don't close that, but if he pressed the close button of your form, close it. Then you should distinguish these two situations, then you can declare 'm_bYesIReallyMeanIt' bool variable as default value of 'false' and when the user pressed 'Alt+F4' set that to 'true', then in 'FormClosing' event, you can assign 'm_bYesIReallyMeanIt' to 'e.Cancel' . Then we assumed 'm_bYesIReallyMeanIt' means : I really want to not close the form. I don't know what I said though!!

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