I have a MaskedTextBox on my system with the following format (xx) 9xxxx-xxxx for mobile phones that have the digit 9 plus, but in some states they do not have this extra digit thus getting (xx) xxxx-xxxx .
How do I make Mascara interactive to add a plus or minus digit?
You will have to use the String.Format. In your case, you just need to grab the contents of your TextBox and change the format.
It will look something like this:
long cel = Convert.ToInt64(txt.Text);
string celFormatado= String.Format(@"{(00)long cel = Convert.ToInt64(txt.Text);
string celFormatado= String.Format(@"{(00)%pre%00-0000}", cel );
txt.Text = celFormatado;
00-0000}", cel );
txt.Text = celFormatado;