《深入浅出WPF》学习笔记六.手动实现Mvvm

《深入浅出WPF》学习 笔记六.手动实现Mvvm

demo的层级结构,Mvvm常用项目结构

依赖属性基类实现

具体底层原理后续学习中再探讨,可以粗浅理解为,有一个全局对象使用list或者dic监听所有依赖属性,当一个依赖属性变化引发通知时,就会遍历查询对应的字典，通知View层进行处理。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;namespace WpfApp11.ViewModels
{/// <summary>/// viewmodel的基类/// </summary>public class NotificationObject : INotifyPropertyChanged{/// <summary>/// 通知属性变化/// </summary>public event PropertyChangedEventHandler? PropertyChanged;public void RaisePropertyChanged(string propertyName){if (this.PropertyChanged != null){//实际方法,内部可以理解为一个字典对象this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));}}}
}

命令属性基类实现

这个底层原理没了解过，后续学到了再说。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Input;namespace WpfApp11.Commands
{public class DelegateCommand : ICommand{public event EventHandler? CanExecuteChanged;//是否可以执行public bool CanExecute(object? parameter){if (this.CanExecuteFunc == null){return true;}else{this.CanExecuteFunc(parameter);return true;}}//具体执行public void Execute(object? parameter){if (this.ExecuteAction == null){return;}this.ExecuteAction(parameter);}public Action<object> ExecuteAction { get; set; }public Func<object, bool> CanExecuteFunc { get; set; }}
}

View

<Window x:Class="WpfApp11.Views.CalculateView"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:WpfApp11.Views"mc:Ignorable="d"Title="CalculateView" Height="300" Width="300"><Grid><Grid.RowDefinitions><RowDefinition Height="auto"></RowDefinition><RowDefinition Height="auto"></RowDefinition><RowDefinition Height="auto"></RowDefinition><RowDefinition Height="auto"></RowDefinition></Grid.RowDefinitions><StackPanel Grid.Row="0" Orientation="Horizontal" Margin="10"><Label>参数1:</Label><TextBox Height="30" Width="100"  x:Name="tb1"  Text="{Binding Param1}"></TextBox></StackPanel><StackPanel Grid.Row="1" Orientation="Horizontal" Margin="10"><Label>参数2:</Label><TextBox Height="30" Width="100"  x:Name="tb2" Text="{Binding Param2}"></TextBox></StackPanel><StackPanel Grid.Row="2" Orientation="Horizontal" Margin="10"><Label>结果：</Label><TextBox Height="30" Width="100"  x:Name="tb3" Text="{Binding Result}"></TextBox></StackPanel><StackPanel Grid.Row="3" Orientation="Horizontal" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="10"><Button x:Name="btn1" Content="Calculate" Height="30" Width="100" Command="{Binding AddCommand}"></Button></StackPanel></Grid>
</Window>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using WpfApp11.ViewModels;namespace WpfApp11.Views
{/// <summary>/// CalculateView.xaml 的交互逻辑/// </summary>public partial class CalculateView : Window{public CalculateView(){InitializeComponent();this.DataContext = new CalculateViewModel();}}
}

ViewModel

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using WpfApp11.Commands;namespace WpfApp11.ViewModels
{public class CalculateViewModel : NotificationObject{#region 依赖属性private string param1;public string Param1{get { return param1; }set{param1 = value;this.RaisePropertyChanged("Param1");}}private string param2;public string Param2{get { return param2; }set{param2 = value;this.RaisePropertyChanged("Param2");}}private string result;public string Result{get { return result; }set{result = value;this.RaisePropertyChanged("Result");}}#endregion/// <summary>/// 命令属性/// </summary>public DelegateCommand AddCommand {  get; set; }public void Add(object param){this.Result = (Convert.ToInt32(this.Param1) + Convert.ToInt32(this.Param2)).ToString();}public CalculateViewModel(){Param1 = "0";Param2 = "0";Result = "0";this.AddCommand = new DelegateCommand();this.AddCommand.ExecuteAction = new Action<object>(this.Add);}}
}

App

<Application x:Class="WpfApp11.App"xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"xmlns:local="clr-namespace:WpfApp11"StartupUri="Views/CalculateView.xaml"><Application.Resources></Application.Resources>
</Application>