Reflection on structure differs from class - but only in code

Question

Code snippet:

Dim target As Object
\' target gets properly set to something of the desired type
Dim field As FieldInfo = target.GetType.GetField(\"fieldName\         


        

Answer 1

Well, you haven't shown all your code - in particular, where you're setting target and how you're checking the value of the field afterwards.

Here's an example which shows it working fine in C# though:

using System;
using System.Reflection;

struct Foo
{
    public int x;
}

class Test
{
    static void Main()
    {
        FieldInfo field = typeof(Foo).GetField("x");

        object foo = new Foo();
        field.SetValue(foo, 10);
        Console.WriteLine(((Foo) foo).x);
    }
}

(I'm pretty sure the choice of language isn't relevant here, but with more code we could tell for certain.) My strong suspicion is that you're doing something like:

Foo foo = new Foo();
object target = foo;
// SetValue stuff

// What do you expect foo.x to be here?

The value of foo in the snippet above won't have changed - because on the second line, the value is copied when it's boxed. You'd need to unbox and copy again afterwards:

foo = (Foo) target;

If that's not it, please show a short but complete program which demonstrates the problem.