Enum Extension Method is not showing

Question

I'm trying to add new/extension method for Enum but the extension method is not showing on intellisense method list. Please help here's my code.

Extension:

public static class EnumExtensions
    {
        public static string GetDescriptionAttr(this Enum value,string key)
        {
            var type = value.GetType();
            var memInfo = type.GetMember(key);
            var attributes = memInfo[0].GetCustomAttributes(typeof(DescriptionAttribute),
                false);
            var description = ((DescriptionAttribute)attributes[0]).Description;
            return description;
        }
    }

Trying to call the result from other class (both caller and extension are in the same project)

Answer 1

Extension methods can be applied on instances only

public static class EnumExtensions {
  // This extension method requires "value" argument
  // that should be an instance of Enum class 
  public static string GetDescriptionAttr(this Enum value, string key) {
    ...
  }
}

...

public enum MyEnum {
  One, 
  Two,
  Three
}

Enum myEnum = MyEnum.One;

// You can call extension method on instance (myEnum) only
myEnum.GetDescriptionAttr("One");

Answer 2

You should use extension method for an instance of your enum. I have this code and it works properly:

public static string GetDescription(this Enum value)
{
    var attributes = 
        (DescriptionAttribute[])value.GetType().GetField(value.ToString())
        .GetCustomAttributes(typeof(DescriptionAttribute), false);
    return attributes.Length > 0 ? attributes[0].Description : value.ToString();
}

And using of this method shows here:

MyEnum myE = MyEnum.OneOfItemsOfEnum;
string description = myE.GetDescription();