Guid

A Guid is a globally unique identifier. A Guid is a 128 bit integer with 5,316,911,983,139,663,491,615,228,241,121,400,000 possible unique combinations.

A Guid can be used to uniquely identify something in your system, it has a very low probability of being replicated. A Guid can only contain alphanumeric characters and the - hyphen character. Because the Guid has such a low chance of being replicated it is useful in domains that contain many independent systems or clients that need unique identifiers for their data or objects. It is also useful for systems that use caching (or scavenging) as each object instance can also have a unique identifier.

You can create a new Guid by using the static method on the Guid class, NewGuid(). This will generate an entirely new random Guid. You should not use the new keyword to generate a Guid, doing so will result in an empty Guid with all characters set to 0.

var MyGuid = Guid.NewGuid();