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Enum.Format Method

Converts the specified value of a specified enumerated type to its equivalent string representation according to the specified format.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public static string Format(
	Type enumType,
	Object value,
	string format


Type: System.Type
The enumeration type of the value to convert.
Type: System.Object
The value to convert.
Type: System.String
The output format to use.

Return Value

Type: System.String
A string representation of value.


The enumType, value, or format parameter is null.


The enumType parameter is not an Enum type.


The value is from an enumeration that differs in type from enumType.


The type of value is not an underlying type of enumType.


The format parameter contains an invalid value.


format equals "X", but the enumeration type is unknown.

The following table shows the valid values for the format parameter.



"G" or "g"

If value is equal to a named enumerated constant, the name of that constant is returned; otherwise, the decimal equivalent of value is returned.

For example, suppose the only enumerated constant is named Red, and its value is 1. If value is specified as 1, this format returns "Red". However, if value is specified as 2, this format returns "2".


If the FlagsAttribute custom attribute is applied to the enumeration, value is treated as a bit field that contains one or more flags that consist of one or more bits.

If value is equal to a combination of named enumerated constants, a delimiter-separated list of the names of those constants is returned. value is searched for flags, going from the flag with the largest value to the smallest value. For each flag that corresponds to a bit field in value, the name of the constant is concatenated to the delimiter-separated list. The value of that flag is then excluded from further consideration, and the search continues for the next flag.

If value is not equal to a combination of named enumerated constants, the decimal equivalent of value is returned.

"X" or "x"

Represents value in hexadecimal format without a leading "0x".

"D" or "d"

Represents value in decimal form.

"F" or "f"

Behaves identically to "G" or "g", except that the FlagsAttribute is not required to be present on the Enum declaration.

The following example illustrates the use of Format in the context of Enum.

using System;

enum Colors { Red, Green, Blue, Yellow };

public class FormatTest {
    public static void Main() {
        Colors myColor = Colors.Blue;

        Console.WriteLine("My favorite color is {0}.", myColor);
        Console.WriteLine("The value of my favorite color is {0}.", Enum.Format(typeof(Colors), myColor, "d"));
        Console.WriteLine("The hex value of my favorite color is {0}.", Enum.Format(typeof(Colors), myColor, "x"));
// The example displays the following output:
//    My favorite color is Blue.
//    The value of my favorite color is 2.
//    The hex value of my favorite color is 00000002.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.