MouseDown event prevents a form from being moved

[Peter]

Hi

I've discovered a bizarre Windows Forms (VB.NET) behavior that is
resulting in a Form not being able to be moved. To reproduce this:

1) Create yourself a new Windows Application in Visual Studio 2005.
2) A project will be created with one Form (Form 1). Don't add any
code to the project.
3) Run the project and confirm that Form 1 is displayed and you can
drag the Form around your screen by clicking and dragging the Form's
title bar, ie; standard Windows application behaviour.
4) Now add the following code to Form 1:

Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As
System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown

Beep()

End Sub

5) Now run the project again.

You will find that
a) If you click the empty client area of the Form your PC will beep as
you would expect.
b) If you click Form 1's Title Bar or attempt to drag the Form the
application will lock and you can't access the Minimise, Maximise or
Close buttons on the Title Bar. The Form seems to lock for about 30 -
45 secs on my PC.

I discovered this issue in my main project and can't resolve it. It
seems that as soon as you declare a MouseDown event handler this
problem will arise.

Anyone got any ideas about why this happening?

Peter,

 

[Chris Dunaway]

Hi

I've discovered a bizarre Windows Forms (VB.NET) behavior that is
resulting in a Form not being able to be moved. To reproduce this:

1) Create yourself a new Windows Application in Visual Studio 2005.
2) A project will be created with one Form (Form 1). Don't add any
code to the project.
3) Run the project and confirm that Form 1 is displayed and you can
drag the Form around your screen by clicking and dragging the Form's
title bar, ie; standard Windows application behaviour.
4) Now add the following code to Form 1:

Private Sub Form1_MouseDown(ByVal sender As Object, ByVal e As
System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown

Beep()

End Sub

5) Now run the project again.

You will find that
a) If you click the empty client area of the Form your PC will beep as
you would expect.
b) If you click Form 1's Title Bar or attempt to drag the Form the
application will lock and you can't access the Minimise, Maximise or
Close buttons on the Title Bar. The Form seems to lock for about 30 -
45 secs on my PC.

I discovered this issue in my main project and can't resolve it. It
seems that as soon as you declare a MouseDown event handler this
problem will arise.

Anyone got any ideas about why this happening?

Peter,

I cannot duplicate the problem. I was able to move the app by
dragging the title bar as well as click the client area to hear the
beep.

Microsoft Visual Studio 2005
Version 8.0.50727.762 (SP.050727-7600)
Microsoft .NET Framework
Version 2.0.50727 SP2

Installed Edition: Professional

Chris

 

[Peter]

I cannot duplicate the problem.  I was able to move the app by
dragging the title bar as well as click the client area to hear the
beep.

Microsoft Visual Studio 2005
Version 8.0.50727.762  (SP.050727-7600)
Microsoft .NET Framework
Version 2.0.50727 SP2

Installed Edition: Professional

Chris- Hide quoted text -

- Show quoted text -

Chris

Thanks for trying this but I'm a little stumped now. I'm using the
same version of Visual Studio and the .NET Framework as you. I'll try
running the compiled application on another PC and see if the
behaviour is the same.

Peter,