讓UserControl處理Arrow key

前陣子寫了個UserControl, 需要處理Arrow keys.( Up, Down, Left, Right). 但是這四個鍵屬於DialogKey，有兩種解決方案可以使得UserControl在OnKeyDown中處理這四個鍵。

方案一：

重載ProcessDialogKey。

protected override bool ProcessDialogKey(Keys keyData)

{

    if (keyData == Keys.Up || keyData == Keys.Down

          || keyData == Keys.Left || keyData == Keys.Right)

         return false;

     else

         return base.ProcessDialogKey(keyData);

}

 

方案二：

重載ProcessKeyPreview，強制加上Key訊息事件分發的邏輯；然後重載IsInputKey。    

protected override bool ProcessKeyPreview(ref Message m)

{

    if (base.ProcessKeyEventArgs(ref m))

    {

        return true;

     }

     return base.ProcessKeyPreview (ref m);

 }

protected override bool IsInputKey(Keys keyData)

{

    if ( this.Focused )

    {

        Keys keys1 = (keyData & Keys.KeyCode);

        switch (keys1)

        {

            case Keys.Up:

            case Keys.Down:

            case Keys.Left:

            case Keys.Right:

            {

                 return true;

             }

         }

      }

      return base.IsInputKey(keyData);

  }