Question

I have a weird problem and I would like if someone can enlighten me on why is this happening. I have a protected method in a base abstract class as following:

protected T ForExistingEntity<T>(TEntity entity, object key, Func<Entity, T> action) {
    entity = GetByKey(key);
    if (entity != null)
        return action(entity);

    return default(T); 
}

My original call from an inherited class was as follows:

return base.ForExistingEntity(
    new MyEntity(), key, e => {
        e.someFiled = 5;
        return base.Update(e);
    }
);

When this code executes, an exception get raised at the line that reads:

return action(entity);

in the base abstract class. The exception is:

System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)

Now when I modify my call as following:

return base.ForExistingEntity(
    new MyEntity(), key, e => {
        e.someFiled = 5;
        return Update(e);
    }
);

it runs normally without any issues.

Edit:

The Update method is located in the base abstract class and looks like this:

public virtual bool Update(TEntity entity) {
    Condition.Requires(entity, "entity")
        .IsNotNull();

    if (ValidateEntity(entity))
        return Update(entity, true);

    return false;
}

I am starting to think that this is happening because of Update being virtual and the call actually originates in the base class itself? The exception isn’t very helpfull anyway.

Answer 1

This seems to be a known C# compiler bug involving calling a base virtual method from an anonymous method within a generic class. Don’t hesitate to upvote this bug on connect if you want it solved. Fortunately, the workaround is quite simple here.