Generic version of Enum.Parse in C#

user_144424 0
Viewed 24899

I have regularly wondered why C# has not yet implemeted a Generic Enum.Parse

Lets say I have

enum MyEnum
{
   Value1,
   Value2
}

And from an XML file/DB entry I wish to to create an Enum.

MyEnum val = (MyEnum)Enum.Parse(typeof(MyEnum), "value1", true);

Could it not have been implemented as something like

MyEnum cal = Enum.Parse<MyEnum>("value1");

This might seem like a small issue, but it seems like an overlooked one.

Any thoughts?

enums generics c#
7 Answers

It is already implemented in .NET 4 ;) Take a look here.

MyEnum cal;
if (!Enum.TryParse<MyEnum>("value1", out cal))
   throw new Exception("value1 is not valid member of enumeration MyEnum");

Also the discussion here contains some interesting points.

user_1995840

Although constraining to System.Enum isn't allowed by C#, it is allowed in .NET and C# can use types or methods with such constraints. See Jon Skeet's Unconstrained Melody library, which includes code that does exactly what you want.

kvb_829590

The generic version of Parse<TEnum>(String) was introduced in .NET Core 2.0. So you can just write:

    class Program
    {
        static void Main(string[] args)
        {            
            var e = Enum.Parse<MyEnum>("Value1");
            Console.WriteLine($"Enum values is: {e}");
        }
    }

    enum MyEnum
    {
        Value1,
        Value2
    }

Just keep in mind this is not in "old" .Net Framework (.NET 4.8 and less) or in any .NET Standard. You need to target .NET Core >= 2 (or .NET >= 5 since Microsoft dropped "Core" naming).

There is generic version of TryParse<TEnum>(String, TEnum) since .NET Framework 4.0. So you can use it like that:

if (Enum.TryParse<MyEnum>("Value2", out var e2))
{
    Console.WriteLine($"Enum values is: {e2}");
}

or create your own helper method like:

public static class EnumUtils
{
    public static TEnum Parse<TEnum>(String value) where TEnum : struct
    {
        return (TEnum)Enum.Parse(typeof(TEnum), value);
    }
}

...
var e3 = EnumUtils.Parse<MyEnum>("Value1");

and of course you can just use non-generic version until you migrate your project to newer .NET ;)

var e4 = (MyEnum)Enum.Parse(typeof(MyEnum), "Value1");
user_3503840
Related