Is it a bug? Event handler: PictureBox on Form.

[eplayer]

Hi, I am new to C#.
Please give me some advice on this, I would like to know if it is a
bug or not.

My application works similar to paintbrush now.
I use the mouse to draw some lines on a picture box residing on a
form.
I am using mousedown, mousemove and mouseup events of the picture box
to capture the movement of the mouse.

But, I just found out that after I clicked on the picture box and then
dragged the mouse out of the picture box, mouseup event will be
generated.
In my code, I have not use mouseleave event of the picture box.

The firing of mouseup event does not cause me any trouble.
It actually helps me in this case, because I have not consider this
scenario when I wrote the code, my application works as expected.

But, I really want to know if this is a normal behavior.
I could not find any doc about this anywhere.
I do not want my app to stop working in the future.

Thanks,
Stanley

 

[Simon Trew]

Yes, it is normal behaviour unless you have captured the mouse.

S.