I want to use MaskedTextInput to replace textbox with StringFormat, it is pretty simple.
I use it to display the SSN in the certain format when I get it from the service. Also I want to update it as well.
At the beginning, it is empty. I tried to insert a random value. But I can only insert the first two number. Sometimes even I can't insert a letter. There is a red X on the right of the textbox, Not sure what is wrong.