EnumExtensions.ConvertTo

EnumExtensions.cs

static class EnumExtensions
{
    public static TargetEnum ConvertTo<TargetEnum>(this Enum source, bool ignoreCase)
        where TargetEnum : struct
    {
        if (!typeof(TargetEnum).IsEnum)
            throw new ArgumentException("T must be an enumerated type");

        string sourceName = Enum.GetName(source.GetType(), source);
        bool parseResult = Enum.TryParse(sourceName, ignoreCase, out TargetEnum result);

        if (!parseResult)
            throw new ArgumentException($"enum name {sourceName} does not exist in TargetEnum enum {typeof(TargetEnum)}.", nameof(source));

        return result;
    }

    public static TargetEnum ConvertTo<TargetEnum>(this Enum source)
        where TargetEnum : struct
    {
        return ConvertTo<TargetEnum>(source, ignoreCase: false);
    }
}

Program.cs

class Program
{
    enum ColorDTO { white, black }
    enum ColorCAPSDTO { WHITE, BLACK }
    enum Color { black, white }
    enum NoColor { }


    static void Main(string[] args)
    {
        Console.WriteLine(ColorDTO.black.ConvertTo<Color>()); //Prints black
        //Console.WriteLine(ColorCAPSDTO.BLACK.ConvertTo<Color>()); //Throws
        Console.WriteLine(ColorCAPSDTO.BLACK.ConvertTo<Color>(ignoreCase: true)); //Prints black	
        //Console.WriteLine(ColorDTO.black.ConvertTo<NoColor>()); //Throws
    }
}