I have a dialog box with an edit box for time in the box. I can fix the length of the edit box to 5 characters, but how can I fix a semi-colon within the edit box so that the user can change the hour or the minutes, but she or he can't delete the semicolon. I saw this technique in a ms program where the user inputs the social security number as xxx-xx-xxxx and the user can't delete the dashes.

I appreciated any type of response, especially an an example as to how to implement this.