C＃如何捕获文本框外的鼠标事件

Question

i need to hide a ListBox when I focus out a textbox. if i click on a different control or use Tab key then the textbox's "Leave" event occurs. But if I click inside the form, on any free space, then focusout doesn't happen. i saw something called mouse capture but i cant implement it.

i tried this:

private void txtProduct_Enter(object sender, EventArgs e)
{
    listProduct.Show();
    UIElement el = (UIElement)sender;
    el.CaptureMouse();
}  

private void MouseClickedElseWhere(object sender, MouseEventArgs e)
{
    if (e.Clicks >= 1)
    {
        txtProduct_Leave(sender, new EventArgs());
    }
}

private void txtProduct_Leave(object sender, EventArgs e)
{
    listProduct.Hide();
}

but obviously it shows error. how do i achieve this? any help?

Answer 1

I had to make click event for my groupboxes even if groupbox doesnt have a click event by default.

//my_page.designer.cs  
this.groupBox2.Click += new System.EventHandler(this.groupBox2_clicked);  

//my_page.cs  
private void groupBox2_clicked(object sender, EventArgs e)
{
    listProduct.Hide();
}