Winforms: how to open combobox properly?

Question

I have a combobox on the winforms. On Enter even I open it:

cbo.DroppedDown = true;

But if I do that the combo opens and closes immediately. What am I doing wrong?

The reason why I use this event is I need to open combo on Tab, when user click tab on the previous control, this combo opens properly. But if user clicks the combo it opens and closes. How to do that properly?

Thanks

Answer 1

I tried it just like this:

private void comboBox1_enter(object sender, EventArgs e)
      {
         comboBox1.DroppedDown = true;
      }

no changes to mouseup or timers. it behaved just as expected. Whether I selected the comboBox with a mouse click or tabbed into it the drop down list appeared and stayed open until I selected something.

I would look to see if there is something else pulling focus off the box.