如果我的应用程序未设置 StartupUri,则不会解析 App.xaml 文件? [英] App.xaml file does not get parsed if my app does not set a StartupUri?
问题描述
背景:我正在使用 MVVM 创建 WPF 应用程序,并使用 DI 容器构建我的 ViewModel
Background: I'm creating a WPF app using MVVM, and using a DI container to build my ViewModels
我的 App.xaml 如下所示:
My App.xaml looks like this:
<Application x:Class="WpfApp.App"
...xmlns etc...
StartupUri="MainWindow.xaml">
<Application.Resources>
<app:ServiceLocator x:Key="serviceLocator" />
</Application.Resources>
</Application>
MainWindow.xaml 如下所示:
MainWindow.xaml looks like this:
<Window x:Class="CompositeMefWpfApp.MainWindow"
...xmlns etc... >
<Control.DataContext>
<Binding Path="MainWindowViewModel" Source="{StaticResource serviceLocator}" />
</Control.DataContext>
现在,这一切正常,但 StartupUri
被硬编码到 XAML 中,这是我不想要的.
按照我找到的几篇博文和文章的指导,我删除了 StartupUri
,并尝试通过在 App.xaml 中挂接 OnStartup
来创建 MainWindow
.cs,像这样:
Now, this all works fine, but the StartupUri
is hardcoded into the XAML, which I don't want.
Following guidance of several blogposts and articles I found, I removed the StartupUri
, and tried to create the MainWindow
by hooking OnStartup
in App.xaml.cs, like this:
protected override void OnStartup( StartupEventArgs e )
{
base.OnStartup(e);
new MainWindow().Show();
}
问题是,应用程序在尝试显示窗口时崩溃,但出现此异常:
The problem is, the app crashes when trying to show the window, with this exception:
找不到名为{serviceLocator}"的资源.资源名称区分大小写.标记文件WpfApp;component/mainwindow.xaml"第 8 行位置 45 中的对象System.Windows.Data.Binding"出错.
Cannot find resource named '{serviceLocator}'. Resource names are case sensitive. Error at object 'System.Windows.Data.Binding' in markup file 'WpfApp;component/mainwindow.xaml' Line 8 Position 45.
据我所知,
部分根本没有从 xaml 文件中读出.我可以在 OnStartup 中放入一些代码来像这样以编程方式添加资源:
As far as I can tell, the <Application.Resources>
section is simply not being read out of the xaml file. I can put some code in the OnStartup to add the resource programatically like this:
Resources.BeginInit();
Resources.Add("serviceLocator", new ServiceLocator());
Resources.EndInit();
然而,这是一个丑陋的黑客,如果我想稍后在 app.xaml 文件中放入其他内容,这对我没有帮助:-(
However that's an ugly hack, and doesn't help me if I wanted to put something else in the app.xaml file later on :-(
我应该挂钩其他事件吗?有没有办法解决这个问题?
Should I be hooking some other event? Is there a way around this?
推荐答案
与其覆盖 OnStartup,不如尝试使用事件:
Rather than overriding OnStartup, try using an event instead:
<Application x:Class="My.App"
xmlns="..."
Startup="Application_Startup"
ShutdownMode="OnExplicitShutdown">
<Application.Resources>
<app:ServiceLocator x:Key="serviceLocator" />
</Application.Resources>
</Application>
背后的代码:
public partial class App : Application
{
public App()
{ }
private void Application_Startup(object sender, StartupEventArgs e)
{
// TODO: Parse commandline arguments and other startup work
new MainWindow().Show();
}
}
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