What's the best practice way to convert enum to string?

Question

I have enum like this:

public enum ObectTypes
{
    TypeOne,
    TypeTwo,
    TypeThree,
    ...
    TypeTwenty
 }

then I need to convert this enum to string. Now Im doing this that way:

public string ConvertToCustomTypeName(ObjectTypes typeObj)
{
    string result = string.Empty;
    switch (typeObj)
    {
        case ObjectTypes.TypeOne: result = "This is type T123"; break;
        case ObjectTypes.TypeTwo: result = "Oh man! This is type T234"; break;
        ...
        case ObjectTypes.TypeTwenty: result = "This is type last"; break;
    }

    return result;
}

Im quite sure that there is better way do do this, Im looking for some good practice solution.

EDIT: There is no one pattern in result string.

Thanks in advance.

Answer 1

I use the [Description] attribute from System.ComponentModel

Example:

public enum RoleType
{
    [Description("Allows access to public information")] Guest = 0,
    [Description("Allows access to the blog")] BlogReader = 4,
}

Then to read from it I do

public static string ReadDescription<T>(T enumMember)
{
    var type = typeof (T);

    var fi = type.GetField(enumMember.ToString());
    var attributes = (DescriptionAttribute[]) 
            fi.GetCustomAttributes(typeof (DescriptionAttribute), false);
    return attributes.Length > 0 ? 
        attributes[0].Description : 
        enumMember.ToString();
}

Then usage

ReadDescription(RoleType.Guest);

Note: this solution assumes a single culture application as nothing was specifically asked about multiple cultures. If you are in a situation that you need to handle multiple cultures I would use the DescriptionAttribute or similar to store a key to a culture aware resource file. While you could store the enum member directly in the .resx file that would create the tightest coupling possible. I see no reason why you would want to couple the internal workings of your application (the enum member names) to key values that exist for internationalization purposes.

Answer 2

If you need a custom string, the best option would be to make a Dictionary< ObjectTypes, string>, and just do a dictionary lookup.

If you're fine with the default ToString() functionality, just use typeObj.ToString();

For the dictionary approach, you could do:

private static Dictionary<ObjectTypes, string> enumLookup;

static MyClass()
{
    enumLookup = new Dictionary<ObjectTypes, string>();
    enumLookup.Add(ObjectTypes.TypeOne, "This is type T123");
    enumLookup.Add(ObjectTypes.TypeTwo, "This is type T234");
    // enumLookup.Add...

}

Your method becomes:

public string ConvertToCustomTypeName(ObjectTypes typeObj)
{
     // Shouldn't need TryGetValue, unless you're expecting people to mess  with your enum values...
     return enumLookup[typeObj];
}