What could cause an assignment to not work?

Question

I am working on a project in C#, and for some reason, when I try to assign a value to an enum variable, the assignment does not happen. I would copy my code, but it is really just a simple assignment. It's something like:

testVar = MyEnum.TYPE_OF_ENUM;

where testVar is of type MyEnum. When I step through this line using the VisualStudio debugger, I can see that the value of testVar does not change. What could possibly make an assignment fail like that?

EDIT:

Ok I will provide more context.

public enum MyEnum1
{
    ONE,
    TWO,
    THREE,
    FOUR,
    FIVE,
    SIX,
    SEVEN,
    EIGHT
}

public enum MyEnum2
{
    A,
    B,
    C,
    D,
    E,
    F
}

public void StateMachine(MyEnum1 state1)
{
    if(state2 == MyEnum2.A)
    {
        switch (state1)
        {
            case MyEnum1.ONE:
                state2 = MyEnum2.B;
                MyFunc(MyEnum2.B);
                break;
            default:
                break;
        }
    }
    else if (state2 == MyEnum2.B)
    {
        switch(state1)
        {
            case MyEnum1.ONE:
                state2 = MyEnum2.B;
                MyFunc(MyEnum2.B);
                break;
            case MyEnum1.THREE:
                state2 = MyEnum2.C;
                MyFunc(MyEnum2.C);
                break;
            default:
                break;                
        }
    }
    // Etcetera
}

The failure occurs on the state2 = whatever assignments. (state2 is a field, not a property)

Answer 1

If your enum has multiple values with the same underlying value, it may appear to not change:

public enum MyEnum {
    One = 1,
    Two = 1,
}

Here, you'd only ever see One. Similarly, a flag enumeration like:

[Flags]
public enum MyEnum {
    One = 1,
    Two = 2,
    All = One | Two,
}

You'd never see All, just One | Two.

Answer 2

One possibility is property with a broken setter:

class C
{ 
    private MyEnum foo = MyEnum.Something;
    public MyEnum Foo 
    {
        get { return foo; }
        set { }
    }

    void DoSomething()
    {
        Foo = MyEnum.SomethingElse; // does nothing
    }
}

Answer 3

Is MyEnum.TYPE_OF_ENUM the first value in the enum, or is TYPE_OF_ENUM assigned to a integer value of 0?

A non-initialized enum will be set to 0, so it may already match.

Otherwise, it is much more likely that you have something else going on that you haven't noticed yet.