How do I use reflection to get properties explicitly implementing an interface?

Question

More specifically, if I have:

public class TempClass : TempInterface
{

    int TempInterface.TempProperty
    {
     get;
     set;
    }
    int TempInterface.TempProperty2
    {
     get;
     set;
    }

    public int TempProperty
    {
     get;
     set;
    }
}

public interface TempInterface
{
    int TempProperty
    {
        get;
        set;
    }
    int TempProperty2
    {
        get;
        set;
    }
}

How do I use reflection to get all the propertyInfos for properties explicitly implementing TempInterface?

Thanks.

Answer 1

It's overly complex. You have to reflect over the methods/properties of the Interface type, see if they exist in your class type, and compare them to see if they're the "same" when they do exist.

If something is in the interface but not the type you're testing, it's an explicit implementation. If it's in both, but different between the two, it's an explicit interface.

Here's a useful blog post with some code for doing the work: http://hyperthink.net/blog/reflecting-over-explicit-interface-implementations/

Answer 2

Jacob's code is missing a filter:

        var props = typeof(TempClass).GetInterfaces().Where(i => i.Name=="TempInterface").SelectMany(i => i.GetProperties());
        foreach (var prop in props)
            Console.WriteLine(prop);

Answer 3

The property getter and setter of an explicitly implemented interface property has an unusual attribute. It's IsFinal property is True, even when it is not a member of a sealed class. Try this code to verify my assertion:

  foreach (AssemblyName name in Assembly.GetEntryAssembly().GetReferencedAssemblies()) {
    Assembly asm = Assembly.Load(name);
    foreach (Type t in asm.GetTypes()) {
      if (t.IsAbstract) continue;
      foreach (MethodInfo mi in t.GetMethods(BindingFlags.NonPublic | BindingFlags.Instance)) {
        int dot = mi.Name.LastIndexOf('.');
        string s = mi.Name.Substring(dot + 1);
        if (!s.StartsWith("get_") && !s.StartsWith("set_")) continue;
        if (mi.IsFinal)
          Console.WriteLine(mi.Name);
      }
    }
  }

Answer 4

Here's a modified solution based on the implementation given in this blog post:

var explicitProperties =
    from prop in typeof(TempClass).GetProperties(
        BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.DeclaredOnly)
    let getAccessor = prop.GetGetMethod(true)
    where getAccessor.IsFinal && getAccessor.IsPrivate
    select prop;

foreach (var p in explicitProperties)
    Console.WriteLine(p.Name);

Answer 5

I had to modify Jacob Carpenter's answer but it works nicely. nobugz's also works but Jacobs is more compact.

var explicitProperties =
from method in typeof(TempClass).GetMethods(BindingFlags.NonPublic | BindingFlags.Instance)
where method.IsFinal && method.IsPrivate
select method;

Answer 6

I think the class you are looking for is System.Reflection.InterfaceMapping.

Type ifaceType = typeof(TempInterface);
Type tempType = typeof(TempClass);
InterfaceMapping map = tempType.GetInterfaceMap(ifaceType);
for (int i = 0; i < map.InterfaceMethods.Length; i++)
{
    MethodInfo ifaceMethod = map.InterfaceMethods[i];
    MethodInfo targetMethod = map.TargetMethods[i];
    Debug.WriteLine(String.Format("{0} maps to {1}", ifaceMethod, targetMethod));
}