Object does not match target type in PropertyInfo

Question

I created some simple codes (see below) trying to get the callback instance from a WCF proxy.  From debugger, I can see I get the pi object with valuable information.  I thought I can get the  IDuplexContextChannel object with these codes below.  But it throws me the exception - "Object does not match target type" in the line of pi.GetValue(proxy, null).  Is "proxy" not the right parameter passed in?  I though it is because pi is derived from proxy.  If no, what should I need to pass in?


Thanks in advance for help!


Here are the codes --

 

                Type proxy = GetProxyType(contractType);

                PropertyInfo pi = proxy.GetProperty("InnerDuplexChannel");

 

                if (pi.GetIndexParameters().Length == 0) {

                    IDuplexContextChannel dcc = (IDuplexContextChannel)pi.GetValue(proxy, null);

                    InstanceContext ic = new InstanceContext(dcc.CallbackInstance);

                }

Answer 1

I think that you should pass an instance of proxy, not its type to GetValue.

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Miha Markic [MVP C#] http://blog.rthand.com

Answer 2

Thanks Miha!

I have modified the line of code - " IDuplexContextChannel dcc = (IDuplexContextChannel)pi.GetValue(proxy, null);"

 to " dcc = (IDuplexContextChannel)pi.GetValue(Activator.CreateInstance(proxy), null);"

Now I have differnt error "[System.MissingMethodException] = {"No parameterless constructor defined for this object."}".  Its stack report is -

   at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandle& ctor, Boolean& bNeedSecurityCheck)
   at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean fillCache)
   at System.RuntimeType.CreateInstanceImpl(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean fillCache)
   at System.Activator.CreateInstance(Type type, Boolean nonPublic)

It is true I don't have a no parameterless constructor.  All the constructors I have are -

"[System.Reflection.RuntimeConstructorInfo] = {Void .ctor(System.ServiceModel.InstanceContext)}
base {System.Reflection.MemberInfo} = {Void .ctor(System.ServiceModel.InstanceContext)}

[System.Reflection.RuntimeConstructorInfo] = {Void .ctor(System.ServiceModel.InstanceContext, System.String)}
base {System.Reflection.MethodBase} = {Void .ctor(System.ServiceModel.InstanceContext, System.String)}

[System.Reflection.RuntimeConstructorInfo] = {Void .ctor(System.ServiceModel.InstanceContext, System.String, System.String)}
base {System.Reflection.MethodBase} = {Void .ctor(System.ServiceModel.InstanceContext, System.String, System.String)}

[System.Reflection.RuntimeConstructorInfo] = {Void .ctor(System.ServiceModel.InstanceContext, System.String, System.ServiceModel.EndpointAddress)}
base {System.Reflection.MethodBase} = {Void .ctor(System.ServiceModel.InstanceContext, System.String, System.ServiceModel.EndpointAddress)}

[System.Reflection.RuntimeConstructorInfo] = {Void .ctor(System.ServiceModel.InstanceContext, System.ServiceModel.Channels.Binding, System.ServiceModel.EndpointAddress)}
base {System.Reflection.MethodBase} = {Void .ctor(System.ServiceModel.InstanceContext, System.ServiceModel.Channels.Binding, System.ServiceModel.EndpointAddress)}

From the stack's tope message "at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandle& ctor, Boolean& bNeedSecurityCheck)", I gue ss that I may be able to replace that line of code by setting the boolean value to true. 

dcc = (IDuplexContextChannel)pi.GetValue(Activator.CreateInstance(proxy, true, true, true, RuntimeMethodHandle, true), null);

But I don't know how to set the RuntimeMethodHandle from the Type object proxy.  Is it possible to get the RuntimeMethodHandle from there?

Thanks all!

 

 

 

Answer 3

Thanks guys.  I guess I got it.  Passing an empty RuntimeMethodHandle may be fine.