Determine MouseButton state during WM_NCHITTEST

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Is there any way to determine the state of the mouse buttons during a
WM_NCHITTEST message? I have a situation where I need to perform custom
logic during a WM_NCHITTEST messsage (by overriding a form's WndProc method),
but the logic should only be implemented if the left mouse button is pressed.
I am familiar with Windows.Forms.C ontrol.MouseBut tons, but that property is
not updated until after the WM_NCHITTEST occurs.

Thanks for any help!
Lance

[Jeffrey Tan[MSFT]]

Hi Lance,

The WM_NCHITTEST message is sent to a window when the cursor moves, or when
a mouse button is pressed or released. Other mouse messages are actually
generated from WM_NCHITTEST message based on the mouse position. If you
wanted to check if the user clicked in non-client area of the form, then I
would recommend you to use WM_NCLBUTTONDOW N or WM_RBUTTONDOWN. This should
help you to determine if the non-client click is using the left or right
mouse button.

If you really wanted to check mouse button in WM_NCHITTEST, I recommend you
to p/invoke GetKeyState() win32 API with VK_LBUTTON and check if the return
value is not zero.

Hope this helps.

Best regards,
Jeffrey Tan
Microsoft Online Community Support
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[=?Utf-8?B?bGpsZXZlbmQy?=]

Hi Jeffrey,

I was able to get it to work based on your information. Thanks so much for
your help.

Lance

[Jeffrey Tan[MSFT]]

Hi Lance,

Thanks for your feedback.

Also, based on the further discussion with Raymond Chen. The return value
of WM_NCHITTEST should not be dependent on volatile state like whether
mouse buttons are down.

The purpose of WM_NCHITTEST is to figure out how your window is arranged.
This is done in response to many things, not just input. For example, an
app might call WindowFromPoint , and the window manager will send
WM_NCHITTEST to figure out which window lies at a particular point on the
screen.

So, WM_NCLBUTTONDOW N or WM_RBUTTONDOWN should be used here. Thanks.

Best regards,
Jeffrey Tan
Microsoft Online Community Support
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Note: The MSDN Managed Newsgroup support offering is for non-urgent issues
where an initial response from the community or a Microsoft Support
Engineer within 1 business day is acceptable. Please note that each follow
up response may take approximately 2 business days as the support
professional working with you may need further investigation to reach the
most efficient resolution. The offering is not appropriate for situations
that require urgent, real-time or phone-based interactions or complex
project analysis and dump analysis issues. Issues of this nature are best
handled working with a dedicated Microsoft Support Engineer by contacting
Microsoft Customer Support Services (CSS) at
http://msdn.microsoft.com/subscripti...t/default.aspx.
=============== =============== =============== =====

This posting is provided "AS IS" with no warranties, and confers no rights.