在MVVM WPF打开新窗口 [英] Opening new window in MVVM WPF

问题描述

我有按钮，我已经绑定这个按钮，在视图模型指挥说OpenWindowCommand。当我点击按钮，我想打开新的窗口。但是创建窗口实例，并表示从视图模型窗口是违反MVVM的。我创建界面像

I have Button and I have bind this button to command in ViewModel say OpenWindowCommand. When I click on button I want to open new window. But creating window instance and showing window from view model is violation of MVVM. I have created interface like

interface IWindowService
{
 void showWindow(object dataContext);
}

和WindowService实现像

and WindowService implements this interface like

class WindowService:IWindowService
{
 public void showWindow(object dataContext)
 {
  ChildWindow window=new ChildWindow();
  window.DataContext=dataContext;
  window.Show();
  }
}

在此I类指定ChildWindow。所以这个类是紧密结合显示ChildWindow。当我想显示另一个窗口，我要实现具有相同的接口和logic.How另一个类我可以让这个类通用的，所以我可以传递任何窗口类的实例，只是将能够打开的任何窗口？
我没有使用任何内置MVVM frameworks.I已经阅读StackOverflow上很多文章，但我无法找到此任何解决方案。

In this class I have specified ChildWindow. So this class is tightly coupled with showing ChildWindow. When I want to show another window,I have to implement another class with same interface and logic.How can I make this class generic so that I can pass just instance of any window and class will be able to open any window? I am not using any built MVVM frameworks.I have read many articles on StackOverflow but I could not found any solution for this.

推荐答案

您说创建窗口实例，并表示从视图模型窗口是违反MVVM的。这是正确的。

You say "creating window instance and showing window from view model is violation of MVVM". This is correct.

您正试图创建一个需要由VM指明类型的视图界面。这是一样多的侵犯。你可能已经从虚拟机中抽象出来的​​界面背后的创作逻辑，但你仍然要求查看作品。

You are now trying to create an interface that takes a type of view specified by the VM. This is just as much of a violation. You may have abstracted away the creation logic behind an interface, but you are still requesting view creations from within the VM.

虚拟机应该只关心创建虚拟机。如果你真的需要一个新的窗口来承载新的虚拟机，然后提供一个界面，你所做的一切，但一个并不需要一个视图。为什么你需要的看法？大多数（VM第一）MVVM项目使用隐式的DataTemplates与特定的虚拟机的视图相关联。虚拟机一无所知他们。

VM's should only care about creating VM's. If you really need a new window to host the new VM, then provide an interface as you have done, but one that does NOT take a view. Why do you need the view? Most (VM first) MVVM projects use implicit datatemplates to associate a view with a particular VM. The VM knows nothing about them.

这样的：

class WindowService:IWindowService
{
    public void ShowWindow(object viewModel)
    {
        var win = new Window();
        win.Content = viewModel;
        win.Show();
    }
}

显然，你需要确保你有你的VM->查看隐含的模板设置在App.xaml中为这个工作。这仅仅是标准的VM第一MVVM。

Obviously you need to make sure you have your VM->View implicit templates set up in app.xaml for this to work. This is just standard VM first MVVM.

例如：

<Application x:Class="My.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:vm="clr-namespace:My.App.ViewModels"
             xmlns:vw="clr-namespace:My.App.Views"
             StartupUri="MainWindow.xaml">
    <Application.Resources>

        <DataTemplate DataType="{x:Type vm:MyVM}">
            <vw:MyView/>
        </DataTemplate>

    </Application.Resources>
</Application>

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