I have an enum
enum myEnum2 { ab, st, top, under, below}
I would like to write a function to test if a given value is included in myEnum
something like that:
private bool EnumContainValue(Enum myEnum, string myValue)
{
return Enum.GetValues(typeof(myEnum))
.ToString().ToUpper().Contains(myValue.ToUpper());
}
But it doesn't work because myEnum parameter is not recognized.
Why not use
Enum.IsDefined(typeof(myEnum), value);
BTW it's nice to create generic Enum<T>
class, which wraps around calls to Enum
(actually I wonder why something like this was not added to Framework 2.0 or later):
public static class Enum<T>
{
public static bool IsDefined(string name)
{
return Enum.IsDefined(typeof(T), name);
}
public static bool IsDefined(T value)
{
return Enum.IsDefined(typeof(T), value);
}
public static IEnumerable<T> GetValues()
{
return Enum.GetValues(typeof(T)).Cast<T>();
}
// etc
}
This allows to avoid all this typeof
stuff and use strongly-typed values:
Enum<StringSplitOptions>.IsDefined("None")
No need to write your own:
// Summary:
// Returns an indication whether a constant with a specified value exists in
// a specified enumeration.
//
// Parameters:
// enumType:
// An enumeration type.
//
// value:
// The value or name of a constant in enumType.
//
// Returns:
// true if a constant in enumType has a value equal to value; otherwise, false.
public static bool IsDefined(Type enumType, object value);
Example:
if (System.Enum.IsDefined(MyEnumType, MyValue))
{
// Do something
}
just use this method
Enum.IsDefined Method - Returns an indication whether a constant with a specified value exists in a specified enumeration
Example
enum myEnum2 { ab, st, top, under, below};
myEnum2 value = myEnum2.ab;
Console.WriteLine("{0:D} Exists: {1}",
value, myEnum2.IsDefined(typeof(myEnum2), value));
What you're doing with ToString() in this case is to:
Enum.GetValues(typeof(myEnum)).ToString()...
instead you should write:
Enum.GetValues(typeof(myEnum).ToString()...
The difference is in the parentheses...
Also can use this:
enum myEnum2 { ab, st, top, under, below }
static void Main(string[] args)
{
myEnum2 r;
string name = "ab";
bool result = Enum.TryParse(name, out r);
}
The result will contain whether the value is contained in enum or not.
public static T ConvertToEnum<T>(this string value)
{
if (typeof(T).BaseType != typeof(Enum))
{
throw new InvalidCastException("The specified object is not an enum.");
}
if (Enum.IsDefined(typeof(T), value.ToUpper()) == false)
{
throw new InvalidCastException("The parameter value doesn't exist in the specified enum.");
}
return (T)Enum.Parse(typeof(T), value.ToUpper());
}
If your question is like "I have an enum type, enum MyEnum { OneEnumMember, OtherEnumMember }
, and I'd like to have a function which tells whether this enum type contains a member with a specific name, then what you're looking for is the System.Enum.IsDefined
method:
Enum.IsDefined(typeof(MyEnum), MyEnum.OneEnumMember); //returns true
Enum.IsDefined(typeof(MyEnum), "OtherEnumMember"); //returns true
Enum.IsDefined(typeof(MyEnum), "SomethingDifferent"); //returns false
If your question is like "I have an instance of an enum type, which has Flags
attribute, and I'd like to have a function which tells whether this instance contains a specific enum value, then the function looks something like this:
public static bool ContainsValue<TEnum>(this TEnum e, TEnum val) where Enum: struct, IComparable, IFormattable, IConvertible
{
if (!e.GetType().IsEnum)
throw new ArgumentException("The type TEnum must be an enum type.", nameof(TEnum));
dynamic val1 = e, val2 = val;
return (val1 | val2) == val1;
}
Hope I could help.
Use the correct name of the enum ( myEnum2
).
Also, if you're testing against a string value you may want to use GetNames
instead of GetValues
.
just cast the enum as:
string something = (string)myEnum;
and now comparison is easy as you like
I think that you go wrong when using ToString().
Try making a Linq query
private bool EnumContainValue(Enum myEnum, string myValue)
{
var query = from enumVal in Enum.GetNames(typeof(GM)).ToList()
where enumVal == myValue
select enumVal;
return query.Count() == 1;
}
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