/// <summary>
/// Processes a command key.
/// </summary>
/// <param name="msg">A <see cref="T:System.Windows.Forms.Message" />, passed by reference, that represents the window message to process.</param>
/// <param name="keyData">One of the <see cref="T:System.Windows.Forms.Keys" /> values that represents the key to process.</param>
/// <returns>
/// true if the character was processed by the control; otherwise, false.
/// </returns>
protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
{
int visItems = this.DropDownHeight / this.ItemHeight;
switch (keyData)
{
case Keys.Down:
case Keys.Right:
this.SelectedIndex = GetNextEnabledItemIndex(this.SelectedIndex, true);
return(true);
case Keys.Up:
case Keys.Left:
this.SelectedIndex = GetNextEnabledItemIndex(this.SelectedIndex, false);
return(true);
case Keys.PageDown:
if (this.SelectedIndex + visItems > this.Items.Count)
{
this.SelectedIndex = GetNextEnabledItemIndex(this.Items.Count, false);
}
else
{
this.SelectedIndex = GetNextEnabledItemIndex(this.SelectedIndex + visItems, true);
}
return(true);
case Keys.PageUp:
if (this.SelectedIndex - visItems < 0)
{
this.SelectedIndex = GetNextEnabledItemIndex(-1, true);
}
else
{
this.SelectedIndex = GetNextEnabledItemIndex(this.SelectedIndex - visItems, false);
}
return(true);
case Keys.Home:
this.SelectedIndex = GetNextEnabledItemIndex(-1, true);
return(true);
case Keys.End:
this.SelectedIndex = GetNextEnabledItemIndex(this.Items.Count, false);
return(true);
case Keys.Enter:
Point pt = NativeMethods.MapPointToClient(dropDownWindow, Cursor.Position);
int idx = this.dropDownWindow.IndexFromPoint(pt.X, pt.Y);
if (idx >= 0 && IsItemEnabled(idx))
{
return(false);
}
this.DroppedDown = false;
return(true);
case Keys.Escape:
this.DroppedDown = false;
return(true);
default:
break;
}
return(base.ProcessCmdKey(ref msg, keyData));
}