preface

 1、GUID：Global Unique Identifier (GUID, Globally Unique Identifier)
 2. The format of GUID is "xxxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxxxxxx", where each x is a hexadecimal number or character in the range 0-9 or a-f

How to generate guids

var uuid = Guid.NewGuid().ToString(); // 9af7f46a-ea52-4aa3-b8c3-9fd484c2af12  
  
var uuidN = Guid.NewGuid().ToString("N"); // e0a953c3ee6040eaa9fae2b667060e09   
  
var uuidD = Guid.NewGuid().ToString("D"); // 9af7f46a-ea52-4aa3-b8c3-9fd484c2af12  
  
var uuidB = Guid.NewGuid().ToString("B"); // {734fd453-a4f8-4c5d-9c98-3fe2d7079760}  
  
var uuidP = Guid.NewGuid().ToString("P"); //  (ade24d16-db0f-40af-8794-1e08e2040df3)  
  
var uuidX = Guid.NewGuid().ToString("X"); // {0x3fa412e3,0x8356,0x428f,{0xaa,0x34,0xb7,0x40,0xda,0xaf,0x45,0x6f}}