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.

Answer 1

I used this solution as it avoids sending keystrokes:

Override the OnCellClick method (if you're subclassing) or subscribe to the CellClick event (if you're altering the DGV from another object rather than as a subclass).

protected override void OnCellClick(DataGridViewCellEventArgs e)
{
    // Normally the user would need to click a combo box cell once to 
    // activate it and then again to drop the list down--this is annoying for 
    // our purposes so let the user activate the drop-down with a single click.
    if (e.ColumnIndex == this.Columns["YourDropDownColumnName"].Index
        && e.RowIndex >= 0
        && e.RowIndex <= this.Rows.Count)
    {
        this.CurrentCell = this[e.ColumnIndex, e.RowIndex];
        this.BeginEdit(false);
        ComboBox comboBox = this.EditingControl as ComboBox;
        if (comboBox != null)
        {
            comboBox.DroppedDown = true;
        }
    }

    base.OnCellContentClick(e);
}