Asp.net Regular expression for from validation

RegExp_Alphabet = "^[a-z A-Z]+";

RegExp_AlphaNumeric = "^[a-z A-Z 0-9]+";

RegExp_Number = "^\\d+$";

RegExp_Decimal = "^\\d+$.d+$";

        

RegExp_Email = "\\w+([-+.']\\w+)*@\\w+([-.]\\w+)*\\.\\w+([-.]\\w+)*";

RegExp_Weibsite = "^(ht|f)tp(s?)\\\\:\\/\\/[0-9a-zA-Z]([-.\\w]*[0-9a-zA-Z])*(:(0-9)*)*(\\/?)([a-zA-Z0-9\\-\\.\\?\\,\'\\/\\\\\\+&%\\$#_]*)?$";

RegExp_Date = "(((0[123456789]|1[0-9]|2[0-9]|3[0-1])(/)(0[123456789]|10|11|12)(/)(([1][9][0-9][0-9])|([2][0][0-9][0-9]))))";

RegExp_DateTime = "(((0[123456789]|1[0-9]|2[0-9]|3[0-1])(/)(0[123456789]|10|11|12)(/)(([1][9][0-9][0-9])|([2][0][0-9][0-9]))) (0[123456789]|10|11|12)(:)([0-5][0-9])(:)([0-5][0-9]) (AM|PM))";

RegExp_IndianPostalcode = "([0-9][0-9][0-9][0-9][0-9][0-9])";