.NET Core 3 WPF MVVM框架 Prism系列之数据绑定
一.安装Prism
1.使用程序包管理控制台
Install-Package Prism.Unity -Version 7.2.0.1367
也可以去掉‘-Version 7.2.0.1367’获取最新的版本
2.使用管理解决方案的Nuget包
在上面或许我们有个疑问?为啥安装prism会跟Prism.Unity有关系,我们知道Unity是个IOC容器,而Prism本身就支持IOC,且目前官方支持几种IOC容器:
1.且unity由于是微软官方的,且支持prism的组件化,由此我推荐使用prism.unity,在官方文档中prism7不支持prism.Mef,Prism 7.1将不支持prism.Autofac
2.安装完prism.unity就已经包含着所有prism的核心库了,架构如下:
二.实现数据绑定
我们先创建Views文件夹和ViewModels文件夹,将MainWindow放在Views文件夹下,再在ViewModels文件夹下面创建MainWindowViewModel类,如下:
xmal代码如下:
<Window x:Class="PrismSample.Views.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:prism="http://prismlibrary.com/" xmlns:local="clr-namespace:PrismSample" mc:Ignorable="d" Title="MainWindow" Height="450" Width="800" prism:ViewModelLocator.AutoWireViewModel="True"> <StackPanel> <TextBox Text="{Binding Text}" Margin="10" Height="100" FontSize="50" Foreground="Black" BorderBrush="Black"/> <Button Height="100" Width="300" Content="Click Me" FontSize="50" Command="{Binding ClickCommnd}"/> </StackPanel> </Window>
ViewModel代码如下:
using Prism.Commands; using Prism.Mvvm; namespace PrismSample.ViewModels { public class MainWindowViewModel:BindableBase { private string _text; public string Text { get { return _text; } set { SetProperty(ref _text, value); } } private DelegateCommand _clickCommnd; public DelegateCommand ClickCommnd => _clickCommnd ?? (_clickCommnd = new DelegateCommand(ExecuteClickCommnd)); void ExecuteClickCommnd() { this.Text = "Click Me!"; } public MainWindowViewModel() { this.Text = "Hello Prism!"; } } }
启动程序:
点击 click Me 按钮:
可以看到,我们已经成功的用prism实现数据绑定了,且View和ViewModel完美的前后端分离
但是现在我们又引出了另外一个问题,当我们不想按照prism的规定硬要将View和ViewModel放在Views和ViewModels里面,又或许自己的项目取名规则各不相同怎么办,这时候就要用到另外几种方法:
1.更改命名规则
如果,公司命名规则很变态,导致项目结构变成这样(这种公司辞职了算了):
首先我们在App需要引入prism,修改‘Application’为‘prism:PrismApplication’且删除StartupUri
xmal代码如下:
<prism:PrismApplication x:Class="PrismSample.App" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:prism="http://prismlibrary.com/" xmlns:local="clr-namespace:PrismSample"> <Application.Resources> </Application.Resources> </prism:PrismApplication>
cs后台代码如下:
using Prism.Unity; using Prism.Ioc; using Prism.Mvvm; using System.Windows; using PrismSample.Viewsb; using System; using System.Reflection; namespace PrismSample { /// <summary> /// Interaction logic for App.xaml /// </summary> public partial class App : PrismApplication { //设置启动起始页 protected override Window CreateShell() { return Container.Resolve<MainWindow>(); } protected override void RegisterTypes(IContainerRegistry containerRegistry) { } //配置规则 protected override void ConfigureViewModelLocator() { base.ConfigureViewModelLocator(); ViewModelLocationProvider.SetDefaultViewTypeToViewModelTypeResolver((viewType) => { var viewName = viewType.FullName.Replace(".Viewsb.", ".ViewModelsa.OhMyGod."); var viewAssemblyName = viewType.GetTypeInfo().Assembly.FullName; var viewModelName = $"{viewName}Test, {viewAssemblyName}"; return Type.GetType(viewModelName); }); } } }
上面这两句是关键:
".Viewsb." 表示View所在文件夹namespace,".ViewModelsa.OhMyGod." 表示ViewModel所在namespace
var viewName = viewType.FullName.Replace(".Viewsb.", ".ViewModelsa.OhMyGod.");
Test表示ViewModel后缀
var viewModelName = $"{viewName}Test, {viewAssemblyName}";
2.自定义ViewModel注册
我们新建一个Foo类作为自定义类,代码如下:
using Prism.Commands; using Prism.Mvvm; namespace PrismSample { public class Foo:BindableBase { private string _text; public string Text { get { return _text; } set { SetProperty(ref _text, value); } } public Foo() { this.Text = "Foo"; } private DelegateCommand _clickCommnd; public DelegateCommand ClickCommnd => _clickCommnd ?? (_clickCommnd = new DelegateCommand(ExecuteClickCommnd)); void ExecuteClickCommnd() { this.Text = "Oh My God!"; } } }
修改App.cs代码:
protected override void ConfigureViewModelLocator() { base.ConfigureViewModelLocator(); ViewModelLocationProvider.Register<MainWindow, Foo>(); //ViewModelLocationProvider.SetDefaultViewTypeToViewModelTypeResolver((viewType) => //{ // var viewName = viewType.FullName.Replace(".Viewsb.", ".ViewModelsa.OhMyGod."); // var viewAssemblyName = viewType.GetTypeInfo().Assembly.FullName; // var viewModelName = $"{viewName}Test, {viewAssemblyName}"; // return Type.GetType(viewModelName); //}); }
运行:
点击按钮:
就算是不注释修改命名规则的代码,我们发现运行结果还是一样,因此我们可以得出结论,
这种直接的,不通过反射注册的自定义注册方式优先级会高点,在官方文档也说明这种方式效率会高点
且官方提供4种方式,其余三种的注册方式如下:
ViewModelLocationProvider.Register(typeof(MainWindow).ToString(), typeof(MainWindowTest));
ViewModelLocationProvider.Register(typeof(MainWindow).ToString(), () => Container.Resolve<Foo>());
ViewModelLocationProvider.Register<MainWindow>(() => Container.Resolve<Foo>());