无法绑定ViewModelLocator

Question

我为商店ViewModels做了一个类

internal class Locator
{
    public MainViewModel MainViewModel { get; } = new MainViewModel();
}

并将其添加到应用程序资源中

<Application x:Class="Marathon.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:Marathon"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
         <local:Locator x:Key="Locator" x:Name="Locator"/>
    </Application.Resources>
</Application>

然后将其定位器绑定到主窗口

<Window x:Class="App.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"
        DataContext="{Binding Source={StaticResource Locator}, Path=MainViewModel}"
        Title="MainWindow" MinHeight="350" MinWidth="525">
    <Grid>
        <Frame Content="{Binding Page}"></Frame>
    </Grid>
</Window>

它起作用了。

当我向页面添加绑定(DataContext)时。它抛出一个异常(System.Windows.Markup.XamlParseException，Cannot find resource named 'Locator'.)。

<Page x:Class="App.Pages.StartPage"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
      mc:Ignorable="d"
      DataContext="{Binding Source={StaticResource Locator}, Path=MainViewModel}"
      Title="StartPage">
    <Grid>
        
    </Grid>
</Page>

如何将DataContext绑定到页面？

Answer 1

在定位器实例的App.xaml声明中不需要x:Name，x:Key就足够了

Answer 2

当您在视图模型中实例化Page本身时，最容易出现错误。

视图模型不应该创建Page对象。尝试返回Uri并绑定到Source属性：

<Window x:Class="App.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"
        DataContext="{Binding Source={StaticResource Locator}, Path=MainViewModel}"
        Title="MainWindow" MinHeight="350" MinWidth="525">
    <Grid>
        <Frame Source="{Binding Page}" />
    </Grid>
</Window>

这应该是可行的：

public class MainViewModel
{
    public Uri Page { get; } = new Uri("Page1.xaml", UriKind.RelativeOrAbsolute);
}