金石之策（一）MVVM

1. 简介

2. 示例

示例下载地址：https://download.csdn.net/download/qq_43572400/88925141

1. 创建C# WPF应用(.NET Framework)工程，WpfApp1
   
   

2. 添加程序集 GalaSoft.MvvmLight
   
   

3. 创建ViewModel文件夹，并创建MainWindowViewModel.cs、ViewModelLocator.cs文件
   

MainWindowViewModel.cs为视图模型类，用于管理应用程序的主要逻辑

public class MainWindowViewModel : ViewModelBase
{
    public MainWindowViewModel()
    {
        Title = "主界面";
    }
    
    private string _Title;
    public string Title
    {
        get { return _Title; }
        set { Set(ref _Title, value); }
    }
}

ViewModelLocator.cs用于提供 MainWindowViewModel 的实例

public class ViewModelLocator
{
    public ViewModelLocator()
    {
        ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
        SimpleIoc.Default.Register<MainWindowViewModel>();
    }
    public MainWindowViewModel MainWindow
    {
        get
        {
            return ServiceLocator.Current.GetInstance<MainWindowViewModel>();
        }
    }
}

4. 在App.xaml文件中，添加一个资源字典（ResourceDictionary）并定义一个名为"Locator"的静态资源：

<Application x:Class="WpfApp1.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:WpfApp1"
             StartupUri="MainWindow.xaml">
    <Application.Resources>
        <ResourceDictionary>
            <local:ViewModelLocator x:Key="Locator"  xmlns:local="clr-namespace:WpfApp1.ViewModel"/>
        </ResourceDictionary>
    </Application.Resources>
</Application>

5. 在XAML中设置"MainViewModel"作为主窗口的DataContext，使用资源字典（ResourceDictionary）和ViewModelLocator来实现这一点
   MainWindow.xaml

<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"
        mc:Ignorable="d"
        Title="{Binding Title}" Height="450" Width="800">
    <Window.DataContext>
        <Binding Path="MainWindow" Source="{StaticResource Locator}"></Binding>
    </Window.DataContext>
    <Grid>
        
    </Grid>
</Window>

注意：Path定义的名称必须跟ViewModelLocator中声明的函数名一致，否则定义的*ViewModel.cs类不生效。

6. 运行后MainWindowViewModel 设置的标题Title生效