Find a private field with Reflection?

Question

Given this class

class Foo
{
    // Want to find _bar with reflection
    [SomeAttribute]
    private string _bar;

    public string BigBar
    {
        get { return this._bar; }
    }
}

I want to find the private item _bar that I will mark with a attribute. Is that possible?

I have done this with properties where I have looked for an attribute, but never a private member field.

What are the binding flags that I need to set to get the private fields?

Answer 1

Yes, however you will need to set your Binding flags to search for private fields (if your looking for the member outside of the class instance).

The binding flag you will need is: System.Reflection.BindingFlags.NonPublic

Answer 2

typeof(MyType).GetField("fieldName", BindingFlags.NonPublic | BindingFlags.Instance)

Answer 3

You can do it just like with a property:

FieldInfo fi = typeof(Foo).GetField("_bar", BindingFlags.NonPublic | BindingFlags.Instance);
if (fi.GetCustomAttributes(typeof(SomeAttribute)) != null)
    ...

Answer 4

Use BindingFlags.NonPublic and BindingFlags.Instance flags

Reflection.FieldInfo fields[] = myType.GetFields(BindingFlags.NonPublic | BindingFlags.Instance);

Answer 5

One thing that you need to be aware of when reflecting on private members is that if your application is running in medium trust (as, for instance, when you are running on a shared hosting environment), it won't find them -- the BindingFlags.NonPublic option will simply be ignored.