How to call a generic async method using reflection

Question

public interface IBar {
}
public class Bar : IBar {
}
public class Bar2 : IBar {
}
public interface IFoo {
  Task Get(T o) where T : IBar;
}
public         


        

Answer 1

Based on your example you know type of returned object at compile time -> IFoo, so you can use normal casting (IFoo)

var method = typeof(IFoo).GetMethod(nameof(IFoo.Get));
var generic = method.MakeGenericMethod(typeof(IBar));
var task = (Task)generic.Invoke(foo, new [] { bar2 });

IBar result = await task;

If you don't know a type at compile time, then simply use dynamic keyword

var method = typeof(IFoo).GetMethod(nameof(IFoo.Get));
var generic = method.MakeGenericMethod(bar2.GetType());
dynamic task = generic.Invoke(foo, new [] { bar2 });

IBar result = await task;

But if type of the task not a Task at runtime - exception will be thrown
And if you need concrete type of IBar then

var concreteResult = Convert.ChangeType(result, bar2.GetType());