WPF 用户控件依赖注入赋值-Toy模板网

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前言

我一直想组件化得去开发WPF，因为我觉得将复杂问题简单化是最好的

如何组件化开发

WPF 用户控件依赖注入赋值,WPF 入门知识,wpf

主窗口引用

<Window x:Class="WpfApp1.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"
        xmlns:local="clr-namespace:WpfApp1"
        xmlns:MD="http://materialdesigninxaml.net/winfx/xaml/themes"
        xmlns:Views="clr-namespace:WpfApp1.Views"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800" >
    <Window.Resources>
        <Style x:Key="my_text" TargetType="TextBlock">
            <Setter Property="FontSize" Value="30" />
            <Setter Property="Margin" Value="8" />
        </Style>
    </Window.Resources>
    <Window.DataContext >
        <!--需要命名来指定数据源-->
        <local:MainWindowViewModel x:Name="viewModel"/>
    </Window.DataContext>
    <Grid>
        <!--不能直接写TitleValue，Binding数据源会有问题-->
        <Views:ViewA Margin="10"
                Title="{Binding ElementName=viewModel,Path=TitleValue}" />
    </Grid>
</Window>

cs部分

namespace WpfApp1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }

    public class MainWindowViewModel
    {
        public string TitleValue { get; set; } =  "我是测试数据";

    }
}

控件窗口

    <UserControl.DataContext>
        <local:ViewAViewModel />
    </UserControl.DataContext>

    <Grid>
        <TextBlock Text="{Binding Title}" />
    </Grid>

/// <summary>
/// ViewA.xaml 的交互逻辑
/// </summary>
public partial class ViewA : UserControl
{

    public static readonly DependencyProperty TitleProperty;

    /// <summary>
    /// 为了拿到数据源需要定义一下
    /// </summary>
    private ViewAViewModel ViewModel = new ViewAViewModel();
    public ViewA()
    {
        InitializeComponent();
        ViewModel = (ViewAViewModel)DataContext;

    }
    static ViewA()
    {
        //静态构造
        TitleProperty = DependencyProperty.Register("Title", typeof(string), typeof(ViewA),new PropertyMetadata("",
            new PropertyChangedCallback((item, res) =>
            {
                //拿到数据，再次赋值
                var model =(ViewA)item;
                model.ViewModel.Title = (string)res.NewValue;
            })));
    }

    /// <summary>
    /// 只是为了有代码提示，添加依赖属性后不会被调用
    /// </summary>

    public string Title { get; set; }




}
public partial class ViewAViewModel : ObservableObject
{
    /// <summary>
    /// 通知更新
    /// </summary>
    [ObservableProperty]
    private string title = "ViewA Title!";

}

依赖注入代码优化

我将复杂的依赖注入的代码进行了优化，减少了重复内容的输入。

//原代码
TitleProperty = DependencyProperty.Register("Title", typeof(string), typeof(ViewA), new PropertyMetadata(default,
  new PropertyChangedCallback((item, res) =>
  {
      //拿到数据，再次赋值
      var model = (ViewA)item;
      model.ViewModel.Title = (string)res.NewValue;
  })));

//新代码

 TitleProperty = DependencyPropertySet<ViewA, string>("Title", (view, value) =>
 {
     view.ViewModel.Title = value;
 });


/// <summary>
/// 简化依赖注入代码
/// </summary>
/// <typeparam name="View"></typeparam>
/// <typeparam name="Value"></typeparam>
/// <param name="name"></param>
/// <param name="action"></param>
/// <returns></returns>
public static DependencyProperty DependencyPropertySet<View,Value>(string name,Action<View,Value> action) 
    where View : class 
{
    var res=  DependencyProperty.Register(name, typeof(Value), typeof(View), new PropertyMetadata(default,
        new PropertyChangedCallback((item, res) =>
        {
            var model = item as View;
            var value = (Value)res.NewValue;
            if(model != null)
            {
                action(model, value);
            }else
               {
                   throw new Exception("model value is null");
               }
        })));
    return res;
}

更新2023年12月9日

我现在依赖属性扩展封装在一个静态文件里面

namespace BlankApp1.Utils
{
    public class MyWpfExtension<View> where View : class
    {
        
        
        /// <summary>
        /// 简化依赖注入代码
        /// </summary>
        /// <typeparam name="View"></typeparam>
        /// <typeparam name="Value"></typeparam>
        /// <param name="name"></param>
        /// <param name="action"></param>
        /// <returns></returns>
        public DependencyProperty DependencyPropertySet<Value>(string name, Action<View, Value> action)
        {
            var res = DependencyProperty.Register(name, typeof(Value), typeof(View), new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
                new PropertyChangedCallback((item, res) =>
                {
                    var model = item as View;
                    var value = (Value)res.NewValue;
                    if (model != null)
                    {
                        action(model, value);
                    }
                    else
                    {
                        throw new Exception("model value is null");
                    }
                })));
            return res;
        }

    }
}

简化后的依赖注入

记得UserControl.xaml里面绑定你ViewModel。这样的话有代码提示

    <UserControl.DataContext>
    	<!--选择你自己的ViewModel-->
        <ViewModels:TitileViewModel />
    </UserControl.DataContext>

namespace BlankApp1.Views
{
    /// <summary>
    /// TitleView.xaml 的交互逻辑
    /// </summary>
    public partial class TitleView : UserControl
    {

        //这个只是为了代码提示，不涉及逻辑。属性类型按照需求更改。
        public MainWindow MainWindow { get; set; }

        //初始化依赖属性构造器
        public  static readonly MyWpfExtension<TitleView> MyWpfExtension = new MyWpfExtension<TitleView>();

        //这个是简化后的依赖属性
        public static readonly DependencyProperty MainWindowProperty = 
            MyWpfExtension.DependencyPropertySet<MainWindow>("MainWindow", (view, value) =>
        {
            view.TitileViewModel.MainWindow = value;
        });

        /// <summary>
        /// DataContext的数据
        /// </summary>
        public TitileViewModel TitileViewModel { get; set; }

        public TitleView()
        {
            InitializeComponent();
            //拿到DataContext数据重定向
            TitileViewModel = (TitileViewModel)DataContext;
            TitileViewModel.UserName = "小王";
        }
    }
}