Question

I would like to handle a button clicked event in a native c++ class. I have tried creating a ‘handler’ object derived from Object to handle the event and then calling a c++ method. For example I tried the following code:

ref class GButtonHandler sealed : public Object
 {
 public:
     void Button_Click(Object^ sender, RoutedEventArgs^ e)
     {
     }

    GTextBlockHandler(GButtonImpl * pButtonImpl, Button ^ button)
     {
         button->Click += ref new RoutedEventHandler(this, &GTextBlockHandler::Button_Click);
     }
 };

Thinking that I could squirrel away the pButtonImpl pointer and then use it to call a native function in the Button_Clicked function. However on compiling this code, I get the error:

error C3986: '{ctor}': signature of public member contains native type 'GButtonImpl'

So it seems that it does not like me passing in native classes into an ref object. Is there a way to do this?

Note that I am completely new to developing Metro style apps, so bear with me!

Answer 1

Ok, it all makes sense to me now. For anyone else who is interested, the reason you cannot have WinRT Objects with public functions that have native C++ arguments is that these objects would then not be consumable by non C++ code. However, the (obvious?) solution is to make the constructor private and have the class that creates the Object declared as a ‘friend’ class (duh!). Then all is well, the compiler is happy, and I am happy.

Thanks to all who took the time to read this.