Question

I have a WCF service that accepts an object as a parameter that has a URI and Method Name.
What I am trying to do is have a method that will look @ the URI, if it contains the words “localhost” it will use reflection and call a method, of the name that is passed in as a parameter, within the the same class, return a value and continue on.

public class Test
{
     public GetStatResponse GetStat(GetStatRequest request)
     {

        GetStatResponse returnValue = new GetStatResponse();

         if(Helpers.Contains(request.ServiceURI,"localhost", StringComparison.OrdinalIgnoreCase))
         {
             MethodInfo mi = this.GetType().GetMethod(request.ServiceMethod /*, BindingFlags.Public | BindingFlags.IgnoreCase*/);
             returnValue = (GetStatResponse)mi.Invoke(this,null);
         }

The above is the code segment pertaining to this question. I pull the MethodInfo no problem but I am running into issues on the mi.Invoke. The exception that I receive is “Exception has been thrown by the target of an invocation.” With an Inner Exception “Object reference not set to an instance of an object”. I have tried changing the code to (GetStatResponse)mi.Invoke(new Test(), null), with no luck. Test being the class.

I’m open to other suggestions as to how to resolve this, I just thought reflection might be the easiest.

The Method that I am calling with my testing is defined as

public GetStatResponse TestMethod() 
{
         GetStatResponse returnValue = new GetStatResponse(); 
         Stat stat = new Stat();
         Stat.Label = "This is my label";
         Stat.ToolTip = "This is my tooltip";
         Stat.Value = "this is my value"; 

         returnValue.Stat = stat;
         return returnValue;
}

Answer 1

Before calling the method you might want to make sure that the MethodInfo you are pulling through reflection is not null:

MethodInfo mi = this.GetType().GetMethod(
    request.ServiceMethod, 
    BindingFlags.Public | BindingFlags.Instance | BindingFlags.IgnoreCase
);

// Make sure that the method exists before trying to call it
if (mi != null)
{
    returnValue = (GetStatResponse)mi.Invoke(this, null);
}

---

After your update it seems that the exception is thrown inside the method you are calling:

GetStatResponse returnValue = new GetStatResponse(); 
// Don't forget to initialize returnValue.Stat before using it:
returnValue.Stat = new WhateverTheTypeIs();
returnValue.Stat.Label = "This is my label";