IQueryable OfType<T> where T is a runtime Type

Question

I need to be able to get something similar to the following to work:

Type type = ??? // something decided at runtime with .GetType or typeof; object[] entityList = context.Resources.OfType<type>().ToList(); 

Is this possible? I am able to use .NET 4 if anything new in that allows this.

Answer 1

You can call it by reflection:

MethodInfo method = typeof(Queryable).GetMethod("OfType"); MethodInfo generic = method.MakeGenericMethod(new Type[]{ type }); // Use .NET 4 covariance var result = (IEnumerable<object>) generic.Invoke       (null, new object[] { context.Resources }); object[] array = result.ToArray(); 

An alternative would be to write your own OfTypeAndToArray generic method to do both bits of it, but the above should work.

Answer 2

Looks like you’ll need to use Reflection here...

public static IEnumerable<object> DyamicOfType<T>(         this IQueryable<T> input, Type type) {     var ofType = typeof(Queryable).GetMethod("OfType",                      BindingFlags.Static | BindingFlags.Public);     var ofTypeT = ofType.MakeGenericMethod(type);     return (IEnumerable<object>) ofTypeT.Invoke(null, new object[] { input }); }  Type type = // ...; var entityList = context.Resources.DynamicOfType(type).ToList();