Random number

Random number

Hello guys!

I need your help.
This is code behind of my net page (C#).

My problem is check that the random number does not exist in my table tbl_1 where is stored in the field Nr_random.
If the random number generate exist in my table I need generate new number, else register the first random number generate.

how can i do it?
any help?
thank you.

                            Random RandomClass = new Random();
                            int RandomNumber = RandomClass.Next(100000000, 999999999);
                            string vowels = "aeiou";
                            string name = strEMail_user;
                            name = new string(name.Where(c => !vowels.Contains(c)).ToArray());
                            string[] strresult = name.Split('.');
                            string stroutput = strresult[1].Substring(0, 3) + " " + strresult[0].Substring(0, 3);
                            string Nr_random = RandomNumber + "-" + stroutput.Replace(" ", "").ToUpper();

I apologize, but this was a little confusing. You mentioned checking against a db table, but don’t list any db code. The wording of your question was also a bit confusing. Are you trying to generate a random number from existing values in the table, or generate a random number and then only adding it to the table if it isn’t already there?

Also, may I ask: is there a reason for the special formatting you are giving the string that goes into the Nr_random field? If you are just trying to introduce some form of entropy, it might be more efficient to just use Guid.NewGuid() instead.

In any case, a little more clarification is needed.