WPF MVVM - 如何在单击按钮时从MainWindowViewModel显示视图

Question

  

可能重复：
  The best approach to create new window in WPF using MVVM

Hello Friends，

我有两个视图 MainWindowView 和 AddCustomerView 。我在MainwindowView.xmal中有包含按钮的菜单。

如何通过点击按钮从MainWindowViewModel弹出 AddCustomerView。

我的App.xmal.cs for Startup code是..

base.OnStartup(e);
MainWindow window = new MainWindow();
var viewModel = new MainWindowViewModel();
window.DataContext = viewModel;
window.Show();

在buttonexecute代码中显示AddCustomerView的代码是什么。

 public void AddNewCustomerWindowExecute() //This is button handler
 {
     // How to show AddCustomerView from MainWindowViewModel
 }

Answer 1

在视图中处理

可能是最简单的方法。

private void AddCustomerView_Click(object sender, RoutedEventArgs e)
{
    AddCustomerView view = new AddCustomerView(data);
    view.Show();
}

ViewModel公开事件

这有一个缺点：它需要大量手动编码。

public class MainWindowViewModel 
{
    public event EventHandler AddCustomerViewShowed;

    public void AddNewCustomerWindowExecute()
    {
        if (AddCustomerViewShowed != null)
            AddCustomerViewShowed(this, EventArgs.Empty);
    }
}

在视图中处理它

var viewModel = new MainWindowViewModel();
viewModel.AddCustomerViewShowed += (s, e) => new AddCustomerView(data).Show();

处理所有视图的控制器

public class Controller : IController
{
    public void AddCustomer()
    {
        AddCustomerView view = new AddCustomerView(data);
        view.Show();
    }
}

public class MainWindowViewModel 
{
    IController controler;

    public MainWindowViewModel(IController controller)
    {
        this.controller = controller;
    }

    public void AddNewCustomerWindowExecute()
    {
        controller.AddCustomer();
    }
}

介体模式

某些MVVM框架（例如MVVM Light）使用此模式。

public class App // or in the view or somewhere else
{
    public void RegisterMessenger()
    {
        Messenger.Default.Register<AddCustomerMessage>(this, ProcessAddCustomerMessage);            
    }

    private void ProcessAddCustomerMessage(AddCustomerMessage message)
    {
        AddCustomerView view = new AddCustomerView(data);
        view.Show();
    }
}

public class MainWindowViewModel 
{
    public void AddNewCustomerWindowExecute()
    {
        Messenger.Default.Send(new AddCustomerMessage(...));
    }
}

Answer 2

查看这个“深潜MVVM视频”。 Laurent Bugnion展示了IDialogService的概念并很好地解释了这些概念......加上源代码也应该可用...... 这些概念也适用于wpf

http://channel9.msdn.com/Events/MIX/MIX11/OPN03

HTH