当其中一个参数是动态的时，如何获取类型的构造函数？

Question

I have a series of classes with this constructor:

MyClass(Reader reader, dynamic json)  { ... }

I need to instantiate objects in a generic method. To do so I tried to get the constructor thuswise:

class Reader
...
T  Get<T>(string id)
    {
    dynamic  json        = GetData(id);
    var      constructor = typeof(T).GetConstructor(new Type[] { typeof(Reader), typeof(dynamic) });
    return constructor.Invoke(new object[] { this, json });
    }

However, neither dynamic nor typeof(dynamic) is acceptable in this circumstance. What's the appropriate way to do so? The constructor certainly does exist. There does not seem to be a binding flag for this situation.

For the moment, I've created a dead-simple JsonWrapper class as a workaround:

class JsonWrapper
{
JsonWrapper(dynamic json) { Json = json; }
dynamic  Json  { get;  private set; }
}
...
var  constructor = typeof(T).GetConstructor(new Type[] { typeof(Reader), typeof(JsonWrapper) });

I could also call GetConstructors() and take the first entry, as these classes only have the one - but that would be fragile.

Answer 1

However, neither dynamic nor typeof(dynamic) is acceptable in this circumstance.

Consider using typeof(object) instead of typeof(dynamic) .

MSDN says about dynamic that

In most cases, it functions like it has type object.

In particular, the following code fails with error "Type '....JsonWrapper' already defines a member called 'JsonWrapper' with the same parameter types"

public class JsonWrapper
{
    public JsonWrapper(dynamic json) { }
    public JsonWrapper(object json) { }
}