我想自己实现 ViewModelLocator 。所以我实现了世界上最简单的应用程序。我在 this 教程中做了所有事情。但我仍然得到一个异常(exception):
这是这一行:
DataContext="{Binding MainWindowViewModel, Source={StaticResource ViewModelLocator}}">
这是代码:
App.xaml
<Application x:Class="ViewModelLocatorDemo.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:viewModelLocatorDemo="clr-namespace:ViewModelLocatorDemo">
<Application.Resources>
<viewModelLocatorDemo:ViewModelLocator x:Key="ViewModelLocator"/>
</Application.Resources>
</Application>
App.xaml.cs
namespace ViewModelLocatorDemo
{
using System.Windows;
using ViewModelLocatorDemo.Views;
public partial class App : Application
{
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
MainWindow mainWindow = new MainWindow();
mainWindow.Show();
}
}
}
ViewModelLocator.cs
namespace ViewModelLocatorDemo
{
using ViewModels;
public class ViewModelLocator
{
public MainWindowViewModel MainWindowViewModel
{
get { return new MainWindowViewModel(); }
}
}
}
MainWindow.xaml
<Window x:Class="ViewModelLocatorDemo.Views.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Title="MainWindow" Height="300" Width="300"
DataContext="{Binding MainWindowViewModel, Source={StaticResource ViewModelLocator}}">
<Grid>
<Frame x:Name="MainFrame" Margin="50" BorderThickness="2" BorderBrush="Black" />
</Grid>
</Window>
MainWindowViewModel.cs
namespace ViewModelLocatorDemo.ViewModels
{
public class MainWindowViewModel
{
public string MainText { get; set; }
public MainWindowViewModel()
{
MainText = "The first page";
}
}
}
在 this answer 我发现:
所以我在 App.xaml 中有它。如果有人能解释一下这里发生了什么?为什么我收到这个错误?
最佳答案
您遇到了这个错误 WPF - App.xaml file does not get parsed if my app does not set a StartupUri?
从该页面:
从该页面开始,有 3 个解决方案(为了完整性在此处进行总结):
x:Name="App"
<viewModelLocatorDemo:ViewModelLocator x:Key="ViewModelLocator"/>
和 <viewModelLocatorDemo:ViewModelLocator x:Key="ViewModelLocator2"/>
Startup="Application_Startup"
这绝对不是显而易见的,并且很难排除故障,甚至在我自己的搜索中也很难找到答案。希望这个答案能帮助其他人找到另一个答案。
关于c# - 实现自己的 ViewModelLocator,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/35006559/