Able to assign an invalid Enum value via reflection

I've just come across some strange behavior when setting an enum's value via reflection. It seems like I'm able to set an invalid value for the enum:

class EnumReflector
{
    public enum MyEnum
    {
        Option1 = 0,
        Option2,
        Option3
    }

    public MyEnum TheEnum { get; set; }

    public void Test()
    {
        PropertyInfo pi = this.GetType().GetProperty("TheEnum");
        string badValue = "1234";
        object propertyValue = Enum.Parse(pi.PropertyType, badValue, true);

        pi.SetValue(this, propertyValue, null);
    }
}

Now, if I call this:

        EnumReflector e = new EnumReflector();
        e.Test();
        if (e.TheEnum == EnumReflector.MyEnum.Option1 ||
            e.TheEnum == EnumReflector.MyEnum.Option2 ||
            e.TheEnum == EnumReflector.MyEnum.Option3)
        {
            Console.WriteLine("Value is valid");
        }
        else
        {
            Console.WriteLine("Value is invalid: {0} ({1})", e.TheEnum.ToString(), (int)e.TheEnum);
        }

The output is:

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Value is invalid: 1234 (1234)

How can this be? I though one of the very natures of enums is their restricted value-set!

Enums are just integers (of any integer primitive type, which can be specified) with some defined named constants. There is no need for reflection to assign a value which has no named constant:

enum MyEnum {
    None, One, Two
}

MyEnum e = (MyEnum)100;

Compiles and works just fine. Note that this is also the reason for the Enum.IsDefined() static method, which checks if an enum value is a defined value.

Enums are really stricted value-set, but at the compile time. Here is the disadvantage of the reflection: you loose all the compile-time checks, provided by the compiler and operate the values for own responsibility.

You don't even need to resort to reflection:

EnumReflector e = new EnumReflector();

e.TheEnum = (EnumReflector.MyEnum)1234;

if (e.TheEnum == EnumReflector.MyEnum.Option1 ||
    e.TheEnum == EnumReflector.MyEnum.Option2 ||
    e.TheEnum == EnumReflector.MyEnum.Option3)
{
    Console.WriteLine("Value is valid");
}
else
{
    Console.WriteLine("Value is invalid: {0} ({1})",
                      e.TheEnum.ToString(), (int)e.TheEnum);
}