Regular expressions determine IP numbers

1. Regular expressions

             Public Static BOOLCheckip (stringStrIP) {                //string regex = @ "^ (2[0-4]\d | 25[0-5] | [01]?\d? [1-9]) \." +                //@ "(2[0-4]\d | 25[0-5) | [01]?\d?\d) \. "+//@ "(2[0-4]\d | 25[0-5) | [01]?\d?\d) \. "+//@ "(2[0-4]\d | 25[0-5) | [01]?\d?\d) $ ";String regex ="^ (1\\d{2}|2[0-4]\\d|25[0-5]|[ 1-9]\\d| [1-9]) \\."+"(1\\d{2}|2[0-4]\\d|25[0-5]|[ 1-9]\\d|\\d) \ \."+"(1\\d{2}|2[0-4]\\d|25[0-5]|[ 1-9]\\d|\\d) \ \."+"(1\\d{2}|2[0-4]\\d|25[0-5]|[ 1-9]\\d|\\d) $"; if(System.Text.RegularExpressions.Regex.IsMatch (StrIP, Regex)) {return true; }                Else                {                    return false; }            } Public Static BOOLCheckNumber (stringStrText) {String regex="^[1-9]\\d*$";//match numbers and do not start with 0//String regex = "^[0-9]*$"; //Match Numbers                if(System.Text.RegularExpressions.Regex.IsMatch (StrText, Regex)) {return true; }                Else                {                    return false; }            }             Public Static BOOLChecknumout (stringstrnum) {                //String regex = @ "^[\d,]+$";String regex =@"^[\d][\,\d]*$";//match number, comma                if(System.Text.RegularExpressions.Regex.IsMatch (Strnum, Regex)) {return true; }                Else                {                    return false; }            }

            public static void Checkip (TextBox txt, string mes)            {                if (txt. Text.trim ()! = "" &&! Global.Methods.checkIP (txt. Text.trim ()))                {                    txt. Text = "";                    Txt. Focus ();                    if (mes = = "")                        MessageBox.Show ("IP address is not legal", "hint",MessageBoxButtons.OK, messageboxicon.information); else MessageBox.Show (mes + "illegal", "hint",MessageBoxButtons.OK, messageboxicon.information);}}  

  /// <summary>        ///verifies whether a string matches numbers, letters, kanji/// </summary>        /// <param name= "Isnumber" >match numbers or match numbers, letters, kanji</param>        /// <param name= "str" >the input string</param>        /// <param name= "Isreturn" >whether you need to return a string that ignores special characters</param>        /// <returns></returns>        Private BOOLCheckformat (BOOLIsnumber,ref stringStrBOOLIsreturn) {            BOOLresult =false; stringRegex ="^[0-9]*$";//Match Numbers            if(! Isnumber) regex =@"^[\w]+$";//match numbers, letters, kanji            varReg =NewSystem.Text.RegularExpressions.Regex (Regex);//             //var str = this. Text.replace (", " "");            varSB =NewStringBuilder (); if(Reg. IsMatch (str)) {result=true; }            Else            {                if(Isreturn) { for(inti =0; I < Str. Length; i++)                    {                        if(Reg. IsMatch (Str[i]. ToString ())) {sb. Append (Str[i].                        ToString ()); }} str=sb.                ToString (); }            }            returnresult; }    

Regular expressions determine IP numbers