Useful Regular Expression in C#. White space is not allowed (\S)+ Alphabets and Space [a-zA-Z ]+$ Alphabets ^[A-z]+$ Numbers ^[0-9]+$ Alphanumeric ^[a-zA-Z0-9]*$ Email [a-z0-9!#$%&'*+/=?^_`{|}~-]+(? :\\.[a-z0-9!#$%&'*+/=?^_`{|}~- ]+)*@(?:[a-z0-9](?:[a-z0-9-]*[ a-z0-9])?\\.)+[a-z0-9](?:[a- z0-9-]*[a-z0-9])? Mobile no. ^([7-9]{1})([0-9]{9})$ Date Format ( mm/dd/yyyy | mm-dd-yyyy | mm.dd.yyyy ) /^(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\\d\\d+$/ Website URL ^http(s)?://([\\w-]+.)+[\\w-]+ (/[\\w- ./?%&=])?$ Credit Card Numbers Visa ^4[0-9]{12}(?:[0-9]{3})?$ MasterCard ^5[1-5][0-9]{14}$ American Express ^3[47][0-9]{13}$ Decimal number ((\\d+)((\\.\\d{1,2})?))$ IFSC CODE ^[^\s]{4}\d{7}$ PAN CARD ^([a-zA-Z]){5}([0-9]){4}([a-zA-Z]){1}?$