Question

我正在尝试将View与ViewDode中的ViewModel绑定，但它不起作用。

该应用程序是一个非常简单的窗口，有2个文本框。当我在textbox1中输入文本时，textbox2必须自动获取相同的文本。当然，View中的文本框必须绑定到ViewModel中的属性。

我是WPF的新手，我开始绑定Views和ViewModels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洁的分离。我的代码是

的App.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>

MainWindowViewModel：

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");

        }
    }

并实现了这样的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走在正确的轨道上：

视图必须是UserControl，而不是Window，因为它在MainWindow中托管

需要将ViewModel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>

之后你应该启动并运行。我在这里发布了一个深入的例子：wpf bootstrapping datatemplates--the chicken and the egg

Answer 2

您的ViewModel必须实现界面INotifyPropertyChanged并在任何绑定属性值更改时引发PropertyChanged事件，以便您的视图可以知道发生了更改。

Answer 3

DataTemplate sholudnt包含窗口，它可以包含任何类型的控件。

DataTemplate：

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

UserControl：

    <UserControl x:Class="NavigationCleanBinding.Views.MainView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    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>
</UserControl>

窗口：

 <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">

<ContentControl Content={Binding}/>
</Window>

与ResourceDictionary MVVM的WPF数据绑定

3 个答案: