Question

In the application, when special types of objects are created, I need to generate a unique-id for each of them. The objects are created thro’ a factory and have a high possibility of being created in a ‘bulk’ operation. I realize that the ‘Random’ from the framework is not so ‘random’ after all, so I tried appending the time-stamp as follows:

private string GenerateUniqueId() {     Random randomValue = new Random();     return DateTime.Now.Ticks.ToString() + randomValue.Next().ToString(); } 

Unfortunately, even this does not work. For objects that are created in rapid succession, I generate the same Unique Id 🙁

Currently, I am implementing it in a crude way as follows:

private string GenerateUniqueId() {     Random randomValue = new Random();     int value = randomValue.Next();     Debug.WriteLine(value.ToString());     Thread.Sleep(100);     return DateTime.Now.Ticks.ToString() + value.ToString(); } 

Since this is not a very large application, I think a simple and quick technique would suffice instead of implementing an elaborate algorithm.

Please suggest.

Answer 1

A GUID is probably what you’re looking for:

private string GenerateUniqueId() {     return Guid.NewGuid().ToString('N'); } 

If you want a smaller, more manageable ID then you could use something like this:

private string GenerateUniqueId() {     using (var rng = new RNGCryptoServiceProvider())     {         // change the size of the array depending on your requirements         var rndBytes = new byte[8];         rng.GetBytes(rndBytes);         return BitConverter.ToString(rndBytes).Replace('-', '');     } } 

Note: This will only give you a 64-bit number in comparison to the GUID’s 128 bits, so there’ll be more chance of a collision. Probably not an issue in the real world though. If it is an issue then you could increase the size of the byte array to generate a larger id.