Enum.Format Method (Type, Object, String)


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 Shared Function Format (
	enumType As Type,
	value As Object,
	format As String
) As String


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.

Exception Condition

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.

 Enum Colors
 End Enum

Public Class FormatTest
    Public Shared Sub Main()
        Dim myColor As Colors = Colors.Blue

        Console.WriteLine("My favorite color is {0}.", myColor)
        Console.WriteLine("The value of my favorite color is {0}.", [Enum].Format(GetType(Colors), myColor, "d"))
        Console.WriteLine("The hex value of my favorite color is {0}.", [Enum].Format(GetType(Colors), myColor, "x"))
    End Sub 
End Class 
' 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.

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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