According to MSDN the method Guid.ToString(string format)
returns a string representation of the value of this Guid instance, according to the provided format specifier.
Examples:
guidVal.ToString()
orguidVal.ToString("D")
returns 32 hex digits
separated by hyphens:00000000-0000-0000-0000-000000000000
guidVal.ToString("N")
returns 32 hex digits:00000000000000000000000000000000
guidVal.ToString("B")
returns 32 hex digits separated by hyphens, enclosed in braces:{00000000-0000-0000-0000-000000000000}
guidVal.ToString("P")
returns 32 hex digits separated by hyphens, enclosed in parentheses:(00000000-0000-0000-0000-000000000000)