【WPF】IOC控制反转的应用：弹窗但不互相调用ViewModel

全称：Inversion of Control，控制反转
场景：A页面需要调用B/C页面等，防止直接在VM中新建别的页面实例，使用IOC设计架构；
创建Service，在Service中实现页面的实例创建和定义页面输入输出参数。
在MainView中注册A、B、C页面的Service。
A需要调用B时，调用B的Service。

此架构思路可以在MVVM基础上，减少不同模块的耦合。
可以所有模块的页面都注册服务。让VM之间不存在互相调用

手动实现

IOC类

public static class IoC
{private static readonly Dictionary<Type, object> MAP;static IoC(){MAP = new Dictionary<Type, object>();}public static void Register<T>(T instance){MAP[typeof(T)] = instance;}public static T Provide<T>(){if (MAP.TryGetValue(typeof(T), out object obj) && obj is T t){return t;}throw new Exception("No registered service of type " + typeof(T));}
}

IView接口

public interface IView
{/// <summary>/// Close the view with the given result/// </summary>void CloseDialog(bool result);
}

页面B实现IView

public partial class ChildValuePopup : Window, IView
{public ChildValueEditPopupViewModel ViewModel => (ChildValueEditPopupViewModel)this.DataContext;public ChildValuePopup(){InitializeComponent();DataContext = new ChildValueEditPopupViewModel(this);}public void CloseDialog(bool result){this.DialogResult = result;this.Close();}
}

IViewBService页面B的Service接口

public interface IChildValueEditPopupService
{
//打开B页面方法，及其输入输出参数Task<ChildValueEditPopupResult> ChildValueEditPopupOpenAsync(GirdDataModel data);ChildValueEditPopupResult ChildValueEditPopupOpen(GirdDataModel data);
}//输出参数类定义
//IsSuccess是否成功打开B页面
public class ChildValueEditPopupResult : ObservableObject
{public bool IsSuccess { get; set; }private object _setValue;public string code { get; set; }public object setValue { get=>_setValue; set=>OnPropertyChanged(ref _setValue,value); }
}

ViewBService页面B的Service实现

internal class ChildValueEditPopupService : IChildValueEditPopupService
{public ChildValueEditPopupResult ChildValueEditPopupOpen(GirdDataModel data){var popup = new ChildValuePopup();popup.ViewModel.Code = data.code;popup.ViewModel.ChildValues = Copy.DeepCopy( data.childValues);popup.ViewModel.SetValue = data.setValue;bool result = popup.ShowDialog() == true;if (!result) {return new ChildValueEditPopupResult() { IsSuccess = false};}return new ChildValueEditPopupResult(){IsSuccess = true,code = popup.ViewModel.Code,setValue = popup.ViewModel.SetValue,}; }public async Task<ChildValueEditPopupResult> ChildValueEditPopupOpenAsync(GirdDataModel data) {return await Application.Current.Dispatcher.InvokeAsync(() => {return ChildValueEditPopupOpen(data);});}
}

注册服务，全局页面MainView

public MainWindow()
{InitializeComponent();IoC.Register<IChildValueEditPopupService>(new ChildValueEditPopupService());
}

使用服务，页面A打开页面B

private void ChildValueEditPopupOpen(GirdDataModel data) {IChildValueEditPopupService service = IoC.Provide<IChildValueEditPopupService>();ChildValueEditPopupResult res = service.ChildValueEditPopupOpen(data);if (res.IsSuccess) {data.setValue = res.setValue;}
}