How to use Guids in C#?

You should use Guid.NewGuid()

Just a quick explanation for why you need to call NewGuid as opposed to using the default constructor... In .NET all structures (value types like int, decimal, Guid, DateTime, etc) must have a default parameterless constructor that initializes all of the fields to their default value. In the case of Guid, the bytes that make up the Guid are all zero. Rather than making a special case for Guid or making it a class, they use the NewGuid method to generate a new "random" Guid.

It's in System.Guid.

To dynamically create a GUID in code:

Guid messageId = System.Guid.NewGuid();

To see its value:

string x = messageId.ToString();

something = new Guid() equals something = Guid.Empty.

Use Guid.NewGuid(); instead