What is a GUID?
- The globally unique identifier (GUID) is an alphanumeric identifier that indicates the uniqueness of the product installation.
- In many popular software applications, such as Web browsers and media players, GUIDs are used.
- The format of the GUID is "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx", where each x is a hexadecimal number in the range of 0-9 or a-f.
- For example, 6F9619FF-8B86-D011-B42D-00C04FC964FF is a valid GUID value.
- Why use GUIDs?
- No two computers in the world will generate duplicate GUID values.
- GUIDs are primarily used to assign identifiers that must be unique in a network or system that has multiple nodes, multiple computers, and more than one computer.
- On the Windows platform, GUIDs are widely used: Registry, class and interface identifiers, databases, even automatically generated machine names, directory names, and so on.
Example:
String str = System.Guid.NewGuid (). ToString ("N") + "|"
+ System.Guid.NewGuid (). ToString ("D") + "|"
+ System.Guid.NewGuid (). ToString ("B") + "|"
+ System.Guid.NewGuid (). ToString ("P"); Response.Write (str);
Results returned:
- ece4f4a60b764339b94a07c84e338a27|
- 5bf99df1-dc49-4023-a34a-7bd80a42d6bb|
- {2280f8d7-fd18-4c72-a9ab-405de3fcfbc9}|
- (25e6e09f-fb66-4cab-b4cd-bfb429566549)
Specifiers
- format of the return value
- N 32-bit: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
- D 32 digits separated by hyphens: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
- b enclosed in curly braces, delimited by hyphens digits: {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}
- P enclosed in parentheses, 32 digits separated by hyphens: (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)
Introduction to Guid (globally unique identifier)
