c# - WPF 数据与 ResourceDictionary MVVM 绑定(bind)

Question

我试图在 ResourceDictionary 中将 View 与 ViewModel 绑定(bind)，但它不起作用。

该应用程序是一个非常简单的窗口，带有 2 个文本框。当我向 textbox1 键入文本时，textbox2 必须自动获得相同的文本。当然，View 中的文本框必须绑定(bind)到 ViewModel 中的属性。

我是 WPF 的新手，我开始绑定(bind) View 和 View 模型的方式是在 View 的代码隐藏中:

DataContext = new MyViewModel();

现在我正在努力实现更清晰的分离。我的代码是

应用程序.xaml:

<Application x:Class="NavigationCleanBinding.App"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         StartupUri="/Views/MainWindowView.xaml">
    <Application.Resources>
        <ResourceDictionary Source="MainResourceDictionary.xaml" />
    </Application.Resources>
</Application>

MainResourceDictionary.xaml:

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xamlpresentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:Views="clr-namespace:NavigationCleanBinding.Views"
    xmlns:ViewModels="clr-namespace:NavigationCleanBinding.ViewModels">

    <DataTemplate DataType="{x:Type ViewModels:MainWindowViewModel}">
        <Views:MainWindowView />
    </DataTemplate>

</ResourceDictionary>

MainWindowView.xaml:

<Window x:Class="NavigationCleanBinding.Views.MainWindowView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">

<Grid>
    <TextBox Height="23" HorizontalAlignment="Left" Margin="61,14,0,0" 
             Name="textBox1" VerticalAlignment="Top" Width="120" 
             Text="{Binding TestData, Mode=TwoWay,
             UpdateSourceTrigger=PropertyChanged}"/>
    <Label Content="Test:" Height="28" HorizontalAlignment="Left" Margin="12,12,0,0"
      Name="label1" VerticalAlignment="Top" Width="43" />
    <Label Content="Result:" Height="28" HorizontalAlignment="Left" Margin="10,46,0,0"
      Name="label2" VerticalAlignment="Top" />

    <TextBox Height="23" HorizontalAlignment="Left" Margin="61,48,0,0"
             Name="textBox2" VerticalAlignment="Top" Width="120" 

             Text="{Binding TestData, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"/>
    </Grid>
</Window>

主窗口 View 模型:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace NavigationCleanBinding.ViewModels
{
    class MainWindowViewModel
    {
        private String _testData;
        public String TestData
        {
            get { return _testData; }
            set { _testData = value; }
        }

        private MainWindowViewModel()
        {
            _testData = null;
        }
    }
}

更新:

我将属性 TestData 更改为:

public String TestData
    {
        get { return _testData; }
        set
        { 
            _testData = value;
            OnPropertyChanged("TestData");

        }
    }

并像这样实现 INotifyPropertyChanged:

public event PropertyChangedEventHandler PropertyChanged;
    private void OnPropertyChanged(String propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }

Answer 1

所以 user1064519 是在正确的轨道上:

• View 需要是 UserControl，而不是 Window，因为它托管在 MainWindow 中

• ViewModel 需要加载到 MainWindow 中，这是触发 DataTemplate 被发现和加载的原因。

  <Window x:Class="WpfTemplateBootstrap.MainWindow"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:local="clr-namespace:WpfTemplateBootstrap"
      Title="MainWindow" Height="350" Width="525">
      <ContentControl>
          <ContentControl.Content>
              <local:MainWindowViewModel />
          </ContentControl.Content>
      </ContentControl>
  

之后，您应该可以正常运行了。我在这里发布了一个深入的例子:wpf bootstrapping datatemplates--the chicken and the egg