RuntimeBinderException 将泛型类型上的方法作为动态调用

Question

I'm trying to invoke a method on a generic type (generic is also an argument to invoking method) and are hitting RuntimeBinderException that I don't really see how to work around.

As you can see in below example the instance returns the MyHandler instance (as a dynamic ) which I expect to get invoked, but without explicit conversion to the generic type of the DTO ( as MyDto ) it will crash. And my requirement is to determine the type in runtime (as I see the JsonConvert.DeserializeObject(data, type) does, until the point of invocation).

static async Task Main(string[] args)
{
    string dataType = typeof(MyDto).AssemblyQualifiedName;
    string data = JsonConvert.SerializeObject(new MyDto());

    var type = Type.GetType(dataType);
    var dto = JsonConvert.DeserializeObject(data, type);
    var handler = GetHandler();

    await handler.HandleMessageAsync(dto, CancellationToken.None); // throws the RuntimeBinderException   
    await handler.HandleMessageAsync(dto as MyDto, CancellationToken.None); // is able to invoke MyHandler.HandleMessageAsync

}

public static dynamic GetHandler()
{
    // this is simplified logic for locating a handler instance.
    return new MyHandler();
}

The exception thrown in the 1st invocation from example is

Microsoft.CSharp.RuntimeBinder.RuntimeBinderException: 'The best overloaded method match for 'ConsoleApp.MessageHandlerBase<ConsoleApp.MyDto>.HandleMessageAsync(ConsoleApp.MyDto, System.Threading.CancellationToken)' has some invalid arguments'

I don't see how the conversion can make a change to the DTO as they are the same type. So, my question is how I can succeed invoking the method completely dynamically?

This is the simplified DTO and handler service class hierarchy of the real implementation:

public class MyDto 
{
    public int Prop1 { get; set; } = 1;
}

public interface IMessageHandler<in T> where T : class
{
    Task HandleMessageAsync(T dto, CancellationToken cancellationToken);
}

public class MyHandler : IMessageHandler<MyDto>
{
    public Task HandleMessageAsync(MyDto dto, CancellationToken cancellationToken)
    {
        Console.WriteLine("OnError called from " + this);
        return Task.CompletedTask;
    }
}

Answer 1

Can you please try changing type of dto variable from object to dynamic as below -

dynamic dto = JsonConvert.DeserializeObject(data, type);

The final code should something like this -

static async Task Main(string[] args)
{
    string dataType = typeof(MyDto).AssemblyQualifiedName;
    string data = JsonConvert.SerializeObject(new MyDto());

    var type = Type.GetType(dataType);
    dynamic dto = JsonConvert.DeserializeObject(data, type); // declare as dynamic instead of var (declaring as var would default to object type)
    var handler = GetHandler();

    await handler.HandleMessageAsync(dto, CancellationToken.None); // throws the RuntimeBinderException   
    await handler.HandleMessageAsync(dto as MyDto, CancellationToken.None); // is able to invoke MyHandler.HandleMessageAsync

}