How to generate a Uniq Number C#

Question

I want to generate a Uniq Number something like TMP-0001354, TMP will be always same only number will get change, which should not be get duplicate in table.

I want to a exp. code which should be in c#, I'll call that function at the time of inserting the record in table. SQL server database I am using

I am trying this I don't know will it work fine or not.

 private string RandomNumberGenerator()
    {
        int maxSize = 8;
        int minSize = 5;
        char[] chars = new char[62];
        string a;
        a = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
        chars = a.ToCharArray();
        int size = maxSize;
        byte[] data = new byte[1];
        RNGCryptoServiceProvider crypto = new RNGCryptoServiceProvider();
        crypto.GetNonZeroBytes(data);
        size = maxSize;
        data = new byte[size];
        crypto.GetNonZeroBytes(data);
        StringBuilder result = new StringBuilder(size);
        foreach (byte b in data)
        { result.Append(chars[b % (chars.Length - 1)]); }
        return result.ToString();
    }

Some one please help me.

Table? Database Table? DataTable for C#? What kind of table are you talking about? — Adriaan Stander, Jul 27 '12 at 06:10

score 2 · Answer 1 · answered Jul 27 '12 at 06:12

2

System.Guid.NewGuid().ToString()

This generates a unique number. append the constant part to this guid.

answered Jul 27 '12 at 06:12

user1071979

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'TMP-' is just a constant prefix. If we add that prefix to a unique number the compound is unique. The question's main concern is avoiding duplicates rather than a rigid format. the identifier has 2 parts "TMP-" part and "unique number" part. That is how i perceived the question? If the unique number part is rigid w.r.t the number of digits then i do agree with you that GUID's format wont work here. – user1071979 Jul 27 '12 at 06:27

score 2 · Accepted Answer · answered Jul 27 '12 at 06:26

For generate uniq number use this (the number can start with 0):

string number_s = "TMP-" + RandomNumber(0, 9) + RandomNumber(0, 9) + RandomNumber(0, 9) + RandomNumber(0, 9) + RandomNumber(0, 9) + RandomNumber(0, 9) + RandomNumber(0, 9);

or this (is shorter, but will begin with 1):

string number_s = "TMP-" + RandomNumber(1000000, 9999999);

This is the code for RandomNumber:

private static readonly Random random = new Random();
        private static readonly object syncLock = new object();
        public int RandomNumber(int min, int max)
        {
            lock (syncLock)
            { // synchronize
                return random.Next(min, max);
            }
        }

It works nice for me. Hope that I helped you.

score 0 · Answer 3 · answered Jul 27 '12 at 06:11

0

You can use a mini hash, guid, you could also use the time year month day seconds miliseconds, or a timestamp.

there are many ways to make a unique ID

answered Jul 27 '12 at 06:11

JohnnBlade

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score 0 · Answer 4 · answered Jul 27 '12 at 06:15

0

You might try System.Guid.NewGuid, which generates a global unique identifier (GUID).

answered Jul 27 '12 at 06:15

wintermute

55
1
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score 0 · Answer 5 · edited May 23 '17 at 12:13

0

return string.Format("TMP-{0:d}", DateTime.Now.Millisecond);

also see this SO post:

How to Generate Unique Number in C# of 8 digits?

edited May 23 '17 at 12:13

Community

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answered Jul 27 '12 at 06:16

Ria

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How to generate a Uniq Number C#

5 Answers5