C＃动态和扩展方法的解决方案？

Question

I have a method in Base class which calls ( by reflection to another method).

  type.InvokeMember(context.Request["MethodName"],
                    System.Reflection.BindingFlags.InvokeMethod | System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance, 
                    null, 
                    this, 
                    new object[] { context, Jobj });   //  jObj is dynamic

jObj parameter type is dynamic ( can't change this type).

if the MethodName string value is : " getFinanceDetails " so that method is called..

void getFinanceDetails(object contextObj, dynamic obj)
{

  //Here I need to do obj["Inv_num"].ToString().Decrpyt()   ( my extension method).
  //but it goes Bang cause I cant use extension method for dynamic.
  //But I cant also send it decrypted from base cause not all values are encrpyrted.

}

However - I did solve it by using (inside the method):

((object) obj["Inv_num"]).ToString().Decrypt();

But I dont want to cast every time to object , just to enable extension method.

Is there anything I can do with the param type sending to fix it ?

my desire :

I want to be able to do : obj.ToString().Decrpyt() obj["Inv_num"].ToString().Decrpyt()

edit

   public static string Decrypt(this string obj)
        {
            Func<string, string> Decrypt = Encryptions.GetDecryptedCode;
            return Decrypt(obj);

        }

• obj ( in this case is IDictionary<string , object> ) . so I should be able to read properties. (inv_num in this sample.

Answer 1

Probably not exactly the syntax you were looking for but you could call the extension method as a simple static method on the dynamic object:

void getFinanceDetails(object contextObj, dynamic obj)
{
    var decryptedValue = MyExtensions.Decrypt(obj);
}

This obviously assumes that at runtime obj is of the correct type that your extension method operates on. In your question you have shown some obj["Inv_num"] as if obj was a complex type with a property called Inv_num which is of type string. So you might need to adjust the call on the proper type:

var decryptedValue = MyExtensions.Decrypt(obj["Inv_num"]);

Answer 2

Assuming obj["Inv_num"].ToString() already returns the right value, you could easily do it in two steps:

string text = obj["Inv_num"].ToString();
var decrypted = text.Decrypt();

To be honest, it's not clear why getFinanceDetails (which should be changed to follow .NET naming conventions) can't be written as:

void getFinanceDetails(object contextObj, IDictionary<string, object> obj)
{
    var decrypted = obj["Inv_num"].ToString().Decrypt();
}

Do you ever need to call it with something that doesn't implement IDictionary<string, object> ?