Question

I have a form with child controls.
I want when user move mouse over the form, the form will be closed.
So I catch mouse enter and move leave on the form. But if I move mouse on any controls in form, mouse leave event will be also caught.

Please help me to solve this problem. Thanks.

UPDATE:
When the cursor’s position is on the form’s caption region (this region is called non-client region). I move mouse out of this region, I can’t receive the WM_MOUSELEAVE message as well as WM_NCMOUSELEAVE. Please help me in this problem. I want to receive a message when move mouse out of this region. Thanks.

Answer 1

Essentially you want to check if the cursor is in the scope of the control. Here is the solution:

(1) Add a Panel in the form which is the same size as your Form, and move all controls in the form to the panel. It’s easy to change: open MyForm.designer.cs, add the panel, and change all statements like this.Controls.Add(myLabel); to this.myPanel.Controls.Add(myLabel);.

(2) Deal with MouseEnter and MouseLeave events of the panel you added.

myPanel.MouseEnter += (sender, e) =>
{
    //enter
};

myPanel.MouseLeave += (sender, e) =>
{
   if (Cursor.Position.X < myPanel.Location.X 
       || Cursor.Position.Y < myPanel.Location.Y
       || Cursor.Position.X > myPanel.Location.X + myPanel.Width 
       || Cursor.Position.Y > myPanel.Location.Y + myPanel.Height)
   {
       //out of scope
   }
};

(3) Why not use Form in step 2? Why do we need a Panel with the same size? Try it yourself. The narrow border of the form will make you crazy.

(4) You can make the if statements in step 2 to an extension method, which is helpful to furthur usage.