C# How to use get, set and use enums in a class

There are several things wrong here:

• Your enum is private, but your methods are public. Therefore you can't make your methods return type be the enum type, or have parameters with that type
• Your SetDifficulty method has a parameter of just Difficulty - is that meant to be the parameter name or the type?
• Your SetDifficulty method is trying to set the type rather than a field
• Your GetDifficulty method is trying to use enum as a return type, and is then returning a type rather than a field

Basically, you seem to be confused about what your enum declaration is declaring - it's not declaring a field, it's declaring a type (and specifying what the named values of that type are).

I suspect you want:

// Try not to use nested types unless there's a clear benefit.
public enum Difficulty { Easy, Normal, Hard }

public class Foo
{
    // Declares a property of *type* Difficulty, and with a *name* of Difficulty
    public Difficulty Difficulty { get; set; }
}

You can use get/set methods if you really want to make your code look like Java instead of C#:

public enum Difficulty { Easy, Normal, Hard }

public class Foo
{
    private Difficulty difficulty;

    public void SetDifficulty(Difficulty value)
    {
        difficulty = value;
    }

    public Difficulty GetDifficulty()
    {
        return difficulty;
    }
}

You code tries to assign Difficulty a value, when in fact Difficulty is the name of the enum type. I would encourage use of getters and setters as properties instead:

public enum Difficulty { Easy, Normal, Hard };

private Difficulty _difficulty;

public Difficulty CurrentDifficulty
{
    get { return _difficulty; }
    set { _difficulty = value; }
}

This way you can add additional code in the setter for special conditions. To use it you simply do the following:

//set
CurrentDifficulty = Difficulty.Easy;

//get
Difficulty theDifficulty = CurrentDifficulty;

Once you specify an enum using the enum keyword, that enum acts as a type, like a class or struct would.

Here's how you'd implement a property with a custom enum:

public enum _Difficulty { Easy, Normal, Hard };
public _Difficulty Difficulty { get; set; }