LabView: How to pass in parameters to .NET method using “Invoke Method” vi?

Question

I have a .NET class library that I wrote in C++. "public ref class MyClass" defines a method "MyMethod" that takes two System::Int32 parameters.

Here is MyClass first then my question:

namespace MyNetAssembly {    
    public ref class MyClassThatDoesStuff
    {
    public:
        MyClassThatDoesStuff();

        void MyMethod(System::Int32^ number1, System::Int32^ number2);
        property System::Int32 MyProperty{
            int get (){
                return *_result;
            }

            void set(System::Int32 value){
            }
        }
    private:
        int^ _result;
    };
}

Here is the cpp code:

MyNetAssembly::MyClassThatDoesStuff::MyClassThatDoesStuff()
{
    *_result = 0;
}

void MyNetAssembly::MyClassThatDoesStuff::MyMethod(System::Int32^ number1, System::Int32^ number2)
{
    *_result =(*number1 + *number2) * 100;
}

When I load this assembly from LabView 8.5 using "Constructor Node" vi. Then, I try to invoke MyMethod() using an "Invoke Method" vi, I get the parameters to the method to be of "ValuteType" and not "Int32" as I expect to use directly with LabView constants and controls. Rather, when I create a constant by right clicking on the connector for the parameter, I get ".NET Object"!

Please, How can I get LabView to recognize parameter types?

Note: I tried to change parameters from System::Int32^ number1 to System::Int32 number1. That did not help either.

Answer 1

I think I figured it out! Apparently, there is something funny happens within the vi file itself. If there is a .NET Constructor Node with an assembly defined, then rebuilding the assembly in Visual Studio and updating the Constructor Node does not have an effect over imported method signatures. Therefore, MyMethod(System::Int32 number1, System::Int32 number2, System::String^ str) was no were to be seen.

So, what worked for me is the following:

1. I deleted *Constructor Node* and *Invoke Node* from vi, then saved.
2. To pass integer values to MyMethode here is the method definition that worked for me:

   MyMethod(System::Int32 number1, System::Int32 number2, System::String^ str)
   

   I think the "ValueType" term I saw in LabView means that it requires a value type for Int32.

It can be confusing when LabView have you under the impression that it has completely updated itself when you rebuild your .NET Assembly.

Thanks to everyone who helped. I hope my answer is helpful to anyone else who is working with .NET and LabView.