Getting 'exception has been thrown by the target of an invocation' Exception while calling a WCF method using Reflection

Ramana

15y15.9kAzure

Hi,
   I'm getting "exception has been thrown by the target of an invocation" while calling a wcf service method at the client side using reflection.
   I'm getting the exception while invoking the method at the line:
   object result = oMeth.Invoke(oProxy,@params);

Here is my service :

public string GetData(int value)
        {
            return string.Format("You entered: {0}", value);
        }

my client side code:

ChannelFactory myFactory = default(ChannelFactory);
            myFactory = new ChannelFactory(new BasicHttpBinding(), "http://localhost:3250");
            object oProxy = myFactory.CreateChannel();
            Type oType = oProxy.GetType();
            MethodInfo oMeth = oType.GetMethod("GetData");
            object[] @params = { 3 };
            object result = oMeth.Invoke(oProxy,@params);

Plz help if know the solution.

Thanks & Regards,
Ramana

2 Replies

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Vulpes15y ago
Well, the good news is that reflection must be finding the method OK otherwise you'd get the exception on this line:

MethodInfo oMeth = oType.GetMethod("GetData");

So the question is why can't the method be invoked when, on the face of it, you're doing exactly the right thing with:

object result = oMeth.Invoke(oProxy, @params);

I have known cases where the overload of the Invoke method which takes two parameters doesn't work but the one which takes five parameters does work, though I've never been able to figure out why! According to the documentation, the first overload calls the second one like this:

object result = oMeth.Invoke(oProxy, BindingFlags.Default, null, @params, null);

which presumably won't work either.

I'd try changing that so that you're absolutely explicit about the BindingFlags and the Culture:

var bf = BindingFlags.Instance | BindingFlags.Public | BindingFlags.InvokeMethod | BindingFlags.DeclaredOnly;
var ci = System.Globalization.CultureInfo.InvariantCulture;
object result = oMeth.Invoke(oProxy, bf, null, @params, ci);
Suthish Nair15y ago
Am not sure, the error sometimes occurring due to the destination host/connection string.
Use a Try - Catch block and try to capture inner exception error message.
You need to do a good web search for the solution.

exception has been thrown by the target of an invocation + wcf

exception has been thrown by the target of an invocation