Home Looking for an example where the format string G yields a different output than the format string F (Enum format strings C#)

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Looking for an example where the format string G yields a different output than the format string F (Enum format strings C#)

byMR

November 4, 2024

Here is a MRE:

FileAccessPermissions permissions = FileAccessPermissions.Read | FileAccessPermissions.Special;

Console.WriteLine(permissions.ToString("G"));
Console.WriteLine(permissions.ToString("F"));
Console.WriteLine(permissions.ToString("D"));
Console.WriteLine(permissions.ToString("X"));

[Flags]
enum FileAccessPermissions
{
    None = 0,
    Read = 1,
    Write = 2,
    Execute = 4, 
    Delete = 8,
    Special = 16,
    ReadWrite = Read | Write,
}

To my surprise, I can’t find a singular example where the format specifier G and the F yield different outputs.
I get this for this example:

Read, Special
Read, Special
17
00000011

If I do:
FileAccessPermissions permissions = FileAccessPermissions.ReadWrite;
I get:

ReadWrite
ReadWrite
3
00000003

>Solution :

If you remove the [Flags] attribute, then the two format specifiers will give you different values for eg: (FileAccessPermissions)17:

FileAccessPermissions permissions = (FileAccessPermissions)17;
    
Console.WriteLine(permissions.ToString("G"));
Console.WriteLine(permissions.ToString("F"));
Console.WriteLine(permissions.ToString("D"));
Console.WriteLine(permissions.ToString("X"));

enum FileAccessPermissions
{
    None = 0,
    Read = 1,
    Write = 2,
    Execute = 4, 
    Delete = 8,
    Special = 16,
    ReadWrite = Read | Write,
}

Output:

17
Read, Special
17
00000011

From the documentation:

G or g

If the Flags attribute isn’t set, an invalid value is displayed as a numeric entry.

F or f

If the value can be displayed as a summation of the entries in the enumeration … the string values of each valid entry are concatenated together, separated by commas.