ValidateEnumValueAttribute Class

public class ValidateEnumValueAttribute : ArgumentValidationWithHelpAttribute

Public Class ValidateEnumValueAttribute
	Inherits ArgumentValidationWithHelpAttribute

Dim instance As ValidateEnumValueAttribute

public ref class ValidateEnumValueAttribute : public ArgumentValidationWithHelpAttribute

Inheritance

Object    Attribute    ArgumentValidationAttribute    ArgumentValidationWithHelpAttribute    ValidateEnumValueAttribute

Conversion from a string to an enumeration value can use either the name of the enumeration member, the numeric value of the member, or a comma-separated list of values. By default, however, the EnumConverter class only allows names of enumeration members, and comma-separated values are only allowed if the enumeration has the FlagsAttribute attribute.

Using the ValidateEnumValueAttribute, you can change these behaviors. You can allow numeric values with the AllowNumericValues property, and you can force whether comma-separated values are allowed with the AllowCommaSeparatedValues property.

If numeric values are allowed, they are restricted to values that are defined in the enumeration, unless the enumeration has the FlagsAttribute applied or you set the AllowNonDefinedValues property to TriStateTrue. In that case, for example using the DayOfWeek enumeration, converting a string value of "9" would result in a value of (DayOfWeek)9, even though there is no enumeration member with that value.

In addition, this validator provides usage help listing all the possible values. If the enumeration has a lot of values, you may wish to turn this off by setting the ArgumentValidationWithHelpAttributeIncludeInUsageHelp property to . Similarly, you can avoid listing all the values in the error message by setting the IncludeValuesInErrorMessage property to .

If this validator is used without changing any of its properties on an argument that uses the default EnumConverter, its only effect is to list the values in the usage help. The default behavior of the EnumConverter class is the same as the defaults of this validator.

Reference