regex expression for 11 digit - separated number c# winforms : I am creating a text parser in c# windows form and I want to identify 11 digit phone numbers starting from 0 with a **-** separator, eg 0341-2239548 or 021-34223311 should be converted to 03412239548 and 02134223311 respectively using Regex.Match. I am unable to find the relevant regex expression, can anyone help me please?