ICommand属性如何工作？

Question

I would appreciate help with the following code:

public static ICommand AddNewRecord { get; set; }

The above code is in the App.xaml.cs file of a WPF application. What I don't understand: If I'm correct, an interface cannot be instantiated. So what does the above property do?

Here's code that uses the above property (if that's what it is):

AddNewRecord = new RCommand<IEnumerable>(list =>
  {
    var elementType = list.GetType().GetGenericArguments()[0];

    // More code I can't disclose.

  }, list => list != null);

I am not at liberty to provide the entire code segment.

Answer 1

RCommand<IEnumerable> is a concrete type that implements the ICommand interface and you can set an ICommand property to any type that implements the ICommand interface.

So the code basically creates an RCommand<IEnumerable> and sets the AddNewRecord property to it.

The RCommand<IEnumerable> class in turn seems to accept an Action<IEnumerable> that gets invoked when the command is executed and a Predicate<IEnumerable> that will be returned from the CanExecute method of the command.