Windows Presentation Foundation（WPF）项目不支持AppCommand

Question

我正在尝试运行VS2012（Window 7）中问题“Understanding ICommand implementation without MVVM”的代码，但是收到错误： “Windows Presentation Foundation（WPF）项目不支持AppCommand”

那么，为了运行该问题的代码，我应该怎么做？

MainWindow.xaml.cs：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace seWPFUnderstandingICommandWithout_MVVM
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            AppCommands.AnyCommand.CanExecuteChanged += MyEventHandler;
        }
        private void button1_Click(object sender, RoutedEventArgs e)
        {
            // Nothing for the moment
        }
        private void MyEventHandler(object sender, EventArgs e)
        {
            Console.WriteLine("MyEventHandler called");
        }
     }
     public static class AppCommands
     {
         private static ICommand anyCommand = new MyCommand();

         public static ICommand AnyCommand
         {
             get { return anyCommand; }
         }
     }
     public class MyCommand : ICommand
     {
         bool canExecute;

         public void Execute(object parameter)
         {
            Console.WriteLine("Execute called!");
         }
         public bool CanExecute(object parameter)
         {
             Console.WriteLine("CanExecute called!");
             return CanExecuteResult;
         }
         public event EventHandler CanExecuteChanged;

         public bool CanExecuteResult
         {
             get { return canExecute; }
             set
             {
                 if (canExecute != value)
                 {
                     canExecute = value;
                     var canExecuteChanged = CanExecuteChanged;
                     if (canExecuteChanged != null)
                         canExecuteChanged.Invoke(this, EventArgs.Empty);
                 }
             }
         }
     }
}

Answer 1

如果在AppCommands命名空间中定义了Namespace.To.AppCommads类，则需要在XAML中声明它：

xmlns:local="clr-namespace:Namespace.To.AppCommads"

并像这样使用它：

Command="{x:Static local:AppCommands.AppCommand}"