How to convert GUID to Integer in C#

 To convert GUID to integer without data loss, we cannot use Int32 or Int64.

.NET 4.0 introduced BigInteger struct which is 128 bit integer, and GUID can be easily converted to BigInteger as follows.

For example:

// ex: 6172d469-3e9e-4234-bc53-b90f77212d24  
Guid g = Guid.NewGuid();
Console.WriteLine(g);
// Convert GUID to BigInteger
// ex: 48086539959425620223526443617323504745
BigInteger bigInt = new BigInteger(g.ToByteArray());
Console.WriteLine(bigInt);

g.ToByteArray() converts the GUID to a 16-byte array.

You can use Guid.GetHashCode() to convert guid to 32-bit integer that represents the hash of the Guid.

For example, guid to integer 32

Guid guid = Guid.NewGuid();
int result = guid.GetHashCode();
Console.WriteLine(result);

You can also extract the first 4 bytes from the Guid and combine them into a 32-bit integer.

Guid guid = Guid.NewGuid();
int result = BitConverter.ToInt32(guid.ToByteArray(), 0);
Console.WriteLine(result);

In this example:

• guid.ToByteArray() converts the Guid into a byte array (16 bytes).
• BitConverter.ToInt32() converts the first 4 bytes of the byte array into a 32-bit integer.