![](/img/trans.png)
[英]How to share data between ViewModel class and ICommand classes using MVVM in WPF application?
[英]Share data between ICommand implementation, ViewModel and View
我正在.net中做我的第一個項目,我正在嘗試使用MVVM模式。 如何在ViewModel和ICommand類之間共享數據? 我的ViewModel看起來像這樣:
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));
}
}
}
我將ICommand實現為內部類,但我也嘗試了“獨立”類,但也無法使它正常工作。 我希望我的命令“ test”能夠與WorkClass屬性BookList和Mybook一起使用並共享數據。 (本書是我定義的類,僅包含一些字符串屬性)
我的應用程序現在有兩個窗口,在主窗口中,我創建WorkClass的實例並將其插入到其datacontext中。 然后我將其通過datacontext傳遞到其他這樣的窗口(這是正確的嗎?):
Window1 w = new Window1();
w.DataContext = this.DataContext;
w.ShowDialog();
我希望這些窗口中的命令對此WorkClass實例中的數據執行更改。 我希望我的要求很清楚。 我知道最好使用Internet上可用的RelayCommand或DelegateCommand類,但是由於這是學校的項目,所以我擔心它將被視為復制他人的作品。
如果您需要我從代碼中發布更多內容或解釋我將要編輯的任何內容。
謝謝你的幫助。
您需要通過視圖模型實例初始化命令,並將命令執行委托給視圖模型類的方法
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));
}
}
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.