Hi,

I guess the best solution depends on where in the 'supply-chain' it would be best to apply the conversion in your case. But doing it all in the Textbox does have the advantage of combining the validation and conversion in one place. Of course, if you are going to subclass a Textbox for this then it would probably make sense to use a custom property rather than the Tag property (which may come in handy for a more generic use somewhere down the line)

Best,
Viv

>Another option (I'm up to six now): Lingzhi suggested I look at the tag property to track the real value of the textbox and then display "Y" or "N" and it works as well:
>
>

>public class YesNoBox : TextBox  
>
>    {  
>
>        private Char spaceChar;  
>
> 
>
>        public YesNoBox()  
>
>        {  
>
>            this.spaceChar = Convert.ToChar(" ");  
>
>            this.Tag = "TRUE";  
>
>            this.KeyPress += new KeyPressEventHandler(YesNoBox_KeyPress);  
>
>        }  
>
> 
>
>        void YesNoBox_KeyPress(object sender, KeyPressEventArgs e)  
>
>        {  
>
>            if (e.KeyChar == spaceChar)  
>
>            {  
>
>                ToggleDisplay();   
>
>            }  
>
>            else if (e.KeyChar == 'N' || e.KeyChar == 'n')  
>
>            {  
>
>                base.Tag = "FALSE";  
>
>                base.Text = "N";  
>
>            }  
>
>            else if (e.KeyChar == 'Y' || e.KeyChar == 'y')  
>
>            {  
>
>                base.Tag = "TRUE";  
>
>                base.Text = "Y";  
>
>            }  
>
>            e.Handled = true;  
>
>        }  
>
> 
>
>        private void ToggleDisplay()  
>
>        {  
>
>            switch (this.Tag.ToString())  
>
>            {  
>
>                case "TRUE":  
>
>                    base.Tag = "FALSE";  
>
>                    base.Text = "N";  
>
>                    break;  
>
>                case "FALSE":  
>
>                    base.Tag = "TRUE";  
>
>                    base.Text = "Y";  
>
>                    break;  
>
>                default:  
>
>                    base.Tag = "ERROR";  
>
>                    base.Text = "ERROR";  
>
>                    break;  
>
>            }  
>
>        }  
>
>    }   
>