Wilson,

It would be better to manipulate the textbox.Value directly with code like I posted in the first message.

>The code in the click event of buttons (e.g. '7') :
>
>KEYBOARD '7'
>
>
>If the value type of the text box is char. The value will be '7' and the cursor will go to the right hand side. Then I press the button again. The value will be '77'.
>That works fine.
>
>However, when the value type of the text box is numberic. The value of the text box is '7' when the first time of pressing. Then the cursor will go to the leftest side. Then I press the button again. The display value of the text box is '7 7'. After I press enter, the value is '7'.