`Guid`

A Guid is a "globally unique identifier." This means the value will not conflict with another Guid. We can use Guids to enforce uniqueness.

Databases and interop

We find that databases can use Guids to provide a unique identifier for a row of data. And Guids are used in software systems (file systems and COM).

An example

This simple program uses Guid.NewGuid and creates a Guid. After creating the Guid, we use ToString to see the contents in string form.

Note The Guid does not change each time we access it. After initialization, we can reuse it many times.

Detail We can get bytes from the Guid. We can loop over or test these 16 bytes.

using System;

class Program
{
    static void Main()
    {
        // Generate new Guid.
        var result = Guid.NewGuid();

        // Print the Guid as a string.
        // ... It does not change.
        Console.WriteLine(result.ToString());
        Console.WriteLine(result.ToString());

        // Count the bytes.
        var array = result.ToByteArray();
        Console.WriteLine("BYTE LENGTH:" + array.Length);
    }
}a2934fa2-6f7e-4ac9-8210-681814ac86c4
a2934fa2-6f7e-4ac9-8210-681814ac86c4
BYTE LENGTH:16

Some research

UUIDs are a standardized format. They are often used in databases to enforce uniqueness. File systems (a kind of database) also uses these identifiers.

A summary

To get 16 unique bytes, the Guid.NewGuid method is ideal. We can print (or serialize) the data returned with ToString.