Returns a string representation of the value of this instance of the Guid structure.
Returns a string representation of the value of this Guid instance, according to the provided format specifier.
public string ToString (string format);A single format specifier that indicates how to format the value of this Guid. The format parameter can be "N", "D", "B", "P", or "X". If format is null or an empty string (""), "D" is used.
The value of this Guid, represented as a series of lowercase hexadecimal digits in the specified format.
The value of format is not null, an empty string (""), "N", "D", "B", "P", or "X".
The following table shows the accepted format specifiers for the format parameter. "0" represents a digit; hyphens ("-"), braces ("{", "}"), and parentheses ("(", ")") appear as shown.
| Specifier | Format of return value |
|---|---|
N |
32 digits: 00000000000000000000000000000000 |
D |
32 digits separated by hyphens: 00000000-0000-0000-0000-000000000000 |
B |
32 digits separated by hyphens, enclosed in braces: {00000000-0000-0000-0000-000000000000} |
P |
32 digits separated by hyphens, enclosed in parentheses: (00000000-0000-0000-0000-000000000000) |
X |
Four hexadecimal values enclosed in braces, where the fourth value
is a subset of eight hexadecimal values that is also enclosed in braces: {0x00000000,0x0000,0x0000,{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00}} |
The hexadecimal digits a through f are lowercase in the returned string. To convert them to uppercase, call the String.ToUpper method on the returned string.
原文：https://www.cnblogs.com/chucklu/p/13209084.html