Agnes,
>I got a textbox , When the user new a record , he can type the text in the textbox.
>And after he save the record , the text in the textbox will becomre transparent.Perhaps you could explain *why* you want transparent text? It seems an odd way to do things to me. Do you mean maybe that you want to disable the TextBox? What exactly are you trying to do and why?
However, it's easy enough to do if you need it:
this.MyTextBox.ForeColor = Color.Transparent;
~~Bonnie