Search for a string in Enum and return the Enum

user_192993 0
Viewed 150168

I have an enumeration:

public enum MyColours
{
    Red,
    Green,
    Blue,
    Yellow,
    Fuchsia,
    Aqua,
    Orange
}

and I have a string:

string colour = "Red";

I want to be able to return:

MyColours.Red

from:

public MyColours GetColour(string colour)

So far i have:

public MyColours GetColours(string colour)
{
    string[] colours = Enum.GetNames(typeof(MyColours));
    int[]    values  = Enum.GetValues(typeof(MyColours));
    int i;
    for(int i = 0; i < colours.Length; i++)
    {
        if(colour.Equals(colours[i], StringComparison.Ordinal)
            break;
    }
    int value = values[i];
    // I know all the information about the matched enumeration
    // but how do i convert this information into returning a
    // MyColour enumeration?
}

As you can see, I'm a bit stuck. Is there anyway to select an enumerator by value. Something like:

MyColour(2)

would result in

MyColour.Green
enumeration string c#
13 Answers

check out System.Enum.Parse:


enum Colors {Red, Green, Blue}

// your code:
Colors color = (Colors)System.Enum.Parse(typeof(Colors), "Green");
user_670380

You can cast the int to an enum

(MyColour)2

There is also the option of Enum.Parse

(MyColour)Enum.Parse(typeof(MyColour), "Red")
Guvante_168000

Given the latest and greatest changes to .NET (+ Core) and C# 7, here is the best solution:

var ignoreCase = true;
Enum.TryParse("red", ignoreCase , out MyColours colour);

colour variable can be used within the scope of Enum.TryParse

user_13614600
user_2273320 
var color =  Enum.Parse<Colors>("Green");
user_19419420

You can use Enum.Parse to get an enum value from the name. You can iterate over all values with Enum.GetNames, and you can just cast an int to an enum to get the enum value from the int value.

Like this, for example:

public MyColours GetColours(string colour)
{
    foreach (MyColours mc in Enum.GetNames(typeof(MyColours))) {
        if (mc.ToString().Contains(colour)) {
            return mc;
        }
    }
    return MyColours.Red; // Default value
}

or:

public MyColours GetColours(string colour)
{
    return (MyColours)Enum.Parse(typeof(MyColours), colour, true); // true = ignoreCase
}

The latter will throw an ArgumentException if the value is not found, you may want to catch it inside the function and return the default value.

OregonGhost_203630

Try this method.

public static class Helper
{
  public static T FromStr<T>(string str) where T : struct, System.Enum
    => System.Enum.TryParse<T>(value:str,ignoreCase:true,result:out var result)
    ? result
    : default;
  public static T? FromStrNull<T>(string str) where T : struct, System.Enum
    => System.Enum.TryParse<T>(value: str,ignoreCase: true,result: out var result)
    ? result
    : null;
}

And use it like this

var color = Helper.FromStr<MyColours>("red");
user_3473740

As mentioned in previous answers, you can cast directly to the underlying datatype (int -> enum type) or parse (string -> enum type).

but beware - there is no .TryParse for enums, so you WILL need a try/catch block around the parse to catch failures.

user_1528280

You might also want to check out some of the suggestions in this blog post: My new little friend, Enum<T>

The post describes a way to create a very simple generic helper class which enables you to avoid the ugly casting syntax inherent with Enum.Parse - instead you end up writing something like this in your code:

MyColours colour = Enum<MyColours>.Parse(stringValue);

Or check out some of the comments in the same post which talk about using an extension method to achieve similar.

user_2752820
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