How do I get DataGridView comboboxes to display their drop down list in one click?

Question

After I set "EditOnEnter" to be true, the DataGridViewComboBoxCell still takes two clicks to open if I don't click on the down arrow part of the combo box.

Anyone have any clue how to fix this? I've got my own DataGridView class that I use, so I can easily fix this issue system-wide with a few smart event handlers I hope.

Thanks.

Answer 1

Since you already have the DataGridView's EditMode property set to "EditOnEnter", you can just override its OnEditingControlShowing method to make sure the drop-down list is shown as soon as a combo box receives focus:

public class myDataGridView : DataGridView
{

    protected override void OnEditingControlShowing(DataGridViewEditingControlShowingEventArgs e)
    {
        base.OnEditingControlShowing(e);

        if (e.Control is ComboBox) {
            SendKeys.Send("{F4}");
        }
    }

}

Whenever an edit control in your DataGridView control gets the input focus, the above code checks to see if it is a combo box. If so, it virtually "presses" the F4 key, which causes the drop-down portion to expand (try it when any combo box has the focus!). It's a little bit of a hack, but it works like a charm.