Question

我正在使用.net做我的第一个项目，我正在尝试使用MVVM模式。如何在ViewModel和ICommand类之间共享数据？我的ViewModel看起来像这样：

public class WorkClass : INotifyPropertyChanged
{

    public event PropertyChangedEventHandler PropertyChanged;
    private Book mybook;
    private ObservableCollection<Book> bookList;

    public Book Mybook
    {
        get { return mybook; }
        set
        {
            book = value;
            OnPropertyChanged("Mybook");
        }
    }

    public ObservableCollection<Book> BookList
    {
        get { return bookList; }
        private set
        {
            bookList = value;
            OnPropertyChanged("BookList");
        }
    }

    testCommand2 test = new testCommand2();

    public ICommand Test { get { return test; } }

    private class testCommand2 : ICommand
    {

        public void Execute(object parameter)
        {
            // Do stuff here
        }

        public bool CanExecute(object parameter)
        {
            return true;
        }

        public event EventHandler CanExecuteChanged
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }
    }

    protected void OnPropertyChanged(string name)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(name));
        }
    }
}

我实现了ICommand作为内部类，但我也尝试了一个独立的＆＃34;上课，但也无法使其发挥作用。我想要我的命令＆＃34;测试＆＃34;使用WorkClass属性BookList和Mybook来处理和共享数据。（Book是我定义的类，只包含一些字符串属性）

我的应用程序现在有两个窗口，在主窗口中我创建了WorkClass实例并将其插入到其datacontext中。然后我通过datacontext将它传递到这样的其他窗口（这是正确的吗？）：

Window1 w = new Window1();
w.DataContext = this.DataContext;
w.ShowDialog();

我希望来自这些窗口的命令对来自此WorkClass实例的数据执行更改。我希望很清楚我在问什么。我知道最好使用通过互联网提供的RelayCommand或DelegateCommand类，但由于这是学校的项目，我担心它会被视为复制别人的工作。

如果您需要我从代码中发布更多内容或解释我将编辑的任何内容。

谢谢你的帮助。

Answer 1

您需要通过视图模型实例初始化命令并将命令执行委托给View Model类的方法

public class WorkClass : INotifyPropertyChanged
{

    public WorkClass()
    {
        test = new testCommand2(this);
    }

    // Will be called on command execturion
    public Test2Action()
    {
    }

public event PropertyChangedEventHandler PropertyChanged;
private Book mybook;
private ObservableCollection<Book> bookList;

public Book Mybook
{
    get { return mybook; }
    set
    {
        book = value;
        OnPropertyChanged("Mybook");
    }
}

public ObservableCollection<Book> BookList
{
    get { return bookList; }
    private set
    {
        bookList = value;
        OnPropertyChanged("BookList");
    }
}

testCommand2 test;

public ICommand Test { get { return test; } }

private class testCommand2 : ICommand
{
    private readonly WorkClass _wc;

    public testCommand2(WorkClass wc)
    {
       _wc = wc;
    }

    public void Execute(object parameter)
    {
        _wc.Test2Action();
    }

    public bool CanExecute(object parameter)
    {
        return true;
    }

    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }
}

protected void OnPropertyChanged(string name)
{
    PropertyChangedEventHandler handler = PropertyChanged;
    if (handler != null)
    {
        handler(this, new PropertyChangedEventArgs(name));
    }
}

}

在ICommand实现，ViewModel和View之间共享数据

1 个答案: