K.Mvvm.Ioc.Wpf 3.1.0

Mvvm.Ioc.Wpf

实现WPF开发中MVVM模式和IOC的结合，方便为View注入ViewModel。典型用法如下：

开始

定义View

可以在View的构造函数中通过依赖注入的方式获取指定的DataContext，已解决ViewModel有参构造函数的问题：

• HelloPage.xaml

<Page x:Class="Mvv.Ioc.Wpf.Test.Views.HelloPage"
      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:vm="clr-namespace:Mvv.Ioc.Wpf.Test.ViewModels"
      Title="HelloPage"
      d:DataContext="{d:DesignInstance Type=vm:HelloViewModel}"
      d:DesignHeight="450"
      d:DesignWidth="800"
      mc:Ignorable="d">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition  Height="auto" />
        </Grid.RowDefinitions>
        <TextBlock HorizontalAlignment="Center"
                   VerticalAlignment="Center"
                   FontSize="30"
                   FontWeight="Bold"
                   Text="{Binding Data}" />
        <Button Grid.Row="1" Content="Change" Command="{Binding ChangeCommand}"/>
    </Grid>
</Page>

public partial class HelloPage : Page
{
    public HelloPage()
    {
        DataContext = App.Current.Services.GetRequiredService<IViewModel<HelloPage>>();
        InitializeComponent();
    }
}

还可以通过DataContextExtension可以使用依赖注入来获取ViewModel,解决了ViewModel包含有参构造函数的问题，并保证所有的代码都在xaml文件中进行设置，而无需在后台代码中进行设置：

• WorldPage.xaml

<Page x:Class="Mvv.Ioc.Wpf.Test.Views.WorldPage"
      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:vm="clr-namespace:Mvv.Ioc.Wpf.Test.ViewModels"
      Title="WorldPage"
      d:DataContext="{d:DesignInstance Type=vm:WorldViewModel}"
      d:DesignHeight="450"
      d:DesignWidth="800"
      DataContext="{DataContextExtension}"
      mc:Ignorable="d">

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition />
            <RowDefinition Height="auto" />
        </Grid.RowDefinitions>
        <TextBlock HorizontalAlignment="Center"
                   VerticalAlignment="Center"
                   FontSize="30"
                   FontWeight="Bold"
                   Text="{Binding Data}" />

        <Button Grid.Row="1"
                Content="Reflush"
                Command="{Binding ReflushCommand}" />
    </Grid>
</Page>

也可以明确其ViewModel类型：

DataContext="{DataContextExtension ViewModelType=vm:WorldViewModel}"

如果不指定ViewModelType,则会获取IVewModel<WorldPage>的实例作为DataContext（前提是注入了IVewModel<WorldPage>服务的实现）。

定义ViewModel

internal partial class WorldViewModel(IViewModel<HelloPage> hello) : ObservableObject, IViewModel<WorldPage>
{
    private readonly IViewModel<HelloPage> _hello = hello;

    [ObservableProperty]
    private string _data = $"World !";

    [RelayCommand]
    private void Reflush()
    {
        Data = $"{((HelloViewModel)_hello).Data} {Data}";
    }

}

internal partial class HelloViewModel : ObservableObject, IViewModel<HelloPage>
{
    [ObservableProperty]
    private string _data = "Hello";

    [RelayCommand]
    private void Change()
    {
        Data = "Good";
    }
}

修改App类

public partial class App : WpfApplication
{
    protected override void OnConfigureServices(IServiceCollection services)
    {
        services.AddViewModels(ServiceLifetime.Transient);
    }
}

注意修改App.xaml文件中App类型的父类为WpfApplication:

<WpfApplication x:Class="Mvv.Ioc.Wpf.Test.App"
                xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
                StartupUri="MainWindow.xaml">
    <Application.Resources />
</WpfApplication>

在MainWindow中使用View

<Window
    x:Class="Mvv.Ioc.Wpf.Test.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:local="clr-namespace:Mvv.Ioc.Wpf.Test"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:view="clr-namespace:Mvv.Ioc.Wpf.Test.Views"
    Title="MainWindow"
    Width="800"
    Height="450"
    mc:Ignorable="d">

    <view:HelloPage />
</Window>