How to implement one class to inherit ICommand in release preview build?

Question

Hi,

http://www.codeproject.com/Articles/270415/Visual-Cplusplus-and-WinRT-Metro-Databinding-Basic
This page have a simple sample to use ICommand.

When I want implement one class to inherit ICommand
It will fail

How to implement one class to inherit ICommand in release preview build?
Can give me some sample code?

Thanks

Answer 1

Hey Woody,

I wrote that article - so I was wondering what you meant by "implement one class to inherit" ?

The DelegateCommand class in the example is a class that implements ICommand. Are you getting compiler errors? That code was compiled on the dev preview, so perhaps namespaces or type names may have changed.

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http://blog.voidnish.com

Answer 2

Hi Nishant,

Yes, you got it.
Because ICommand interface have some different in release preview.
But, I don't know how to modify DelegateCommand class.
So, I need some hint or sample code to fix this problem.

Thanks

Answer 3

There isn't a Metro style sample demonstrating this yet. You can get an idea how this should work by reviewing the use of this interface in these articles and a sample project. I would expect a Metro style sample demonstrating this would surface in the near future.

These are targeted for other platforms, but the usage pattern is the same.

Building a Reusable ICommand implementation for Windows Phone Mango MVVM apps

ICommand is like a chocolate cake

Blend for Visual Studio Memory game tutorial files

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Jesse Jiang [MSFT]
MSDN Community Support | Feedback to us

Answer 4

The original code was written on the dev preview, and I don't have a release preview lying around for easy access at the moment, but here's some code that will compile on the consumer preview. (and I assume the CP and RP are fairly close enough that it should compile on the RP too).

delegate void ExecuteDelegate(Object^ parameter);

delegate bool CanExecuteDelegate(Object^ parameter);

ref class DelegateCommand sealed : public ICommand
{
  ExecuteDelegate^ _executeDelegate;
  CanExecuteDelegate^ _canExecuteDelegate;

public:
  DelegateCommand(ExecuteDelegate^ executeDelegate,
    CanExecuteDelegate^ canExecuteDelegate = nullptr)
  {
    _executeDelegate = executeDelegate;
    _canExecuteDelegate = canExecuteDelegate;
  }

  event EventHandler<Object^>^ CanExecuteChanged;

  void Execute(Object^ parameter)
  {
    _executeDelegate(parameter);
  }

  bool CanExecute(Object^ parameter)
  {
    return _canExecuteDelegate == nullptr || _canExecuteDelegate(parameter);
  }
};

Try this and see if it works for you as you expect it to.

---

http://blog.voidnish.com