WPF学习之MVVM笔记

1.code snippet：代码片段

C#中的代码段诸如prop、ctor等通过两下Tab键自动生成固定模式代码的技术，叫code snippet。可以在VS【工具】——【代码片段管理器】——【CSharp】——【VisualC#】看到所有的代码片段。

<?xml version="1.0" encoding="utf-8"?>
<CodeSnippets xmlns="http://schemas.microsoft.com/VisualStudio/2005/CodeSnippet">
    <CodeSnippet Format="1.0.0">
        <Header>
            <Title>propn</Title>
            <Shortcut>propn</Shortcut>
            <Description>类名属性和支持字段的代码片段</Description>
            <Author>Microsoft Corporation</Author>
            <SnippetTypes>
                <SnippetType>Expansion</SnippetType>
            </SnippetTypes>
        </Header>
        <Snippet>
            <Declarations>
                <Literal>
                    <ID>type</ID>
                    <ToolTip>属性类型</ToolTip>
                    <Default>int</Default>
                </Literal>
                <Literal>
                    <ID>property</ID>
                    <ToolTip>属性名</ToolTip>
                    <Default>MyProperty</Default>
                </Literal>
                <Literal>
                    <ID>field</ID>
                    <ToolTip>支持此属性的变量</ToolTip>
                    <Default>myVar</Default>
                </Literal>
            </Declarations>
            <Code Language="csharp">
        <![CDATA[private $type$ $field$;

    public $type$ $property$
    {
        get { return $field$;}
        set 
    { 
            $field$ = value;
      this.RaisePropertyChanged("$property$");
    }
    }
    $end$]]>
            </Code>
        </Snippet>
    </CodeSnippet>
</CodeSnippets>

 2.如何在VS中折叠到定义时 Ctrl+M+O连通#region一同折叠

3.写软件UI的精髓文不如表，表不如图

4.MVVM设计模式详解

　　4.1 MVVM=Model-View-ViewModel

　　4.2 为什么要使用MVVM模式

　　　　团队层面：统一思想方式和实施办法（套路和路数是固定的）

　　　　架构层面：稳定、解耦（橘子皮原理）

　　　　代码层面：可读、可测、可替换

　　4.3 Model：现实世界中对象的抽象结果

　  　　View：UI

　  　　ViewModel：Model for View

　 　　 ViewModel与View的沟通：传递数据<<--->>数据属性 DependencyProperty          传递操作<<-->>命令属性 类似方法、事件与命令

5.MVVM一般要建立的几个文件夹

 6.SimpleMVVM

/// <summary>
/// ViewModel的基类
/// </summary>
class NotificationObject : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    public void RaisePropertyChanged(string propertyName)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

class DelegateCommand : ICommand
{
    public event EventHandler CanExecuteChanged;

    public bool CanExecute(object parameter)
    {
        if (CanExecuteFunc==null)
        {
            return true;
        }
        return CanExecuteFunc(parameter);
    }

    public void Execute(object parameter)
    {
        if (ExecuteAction==null)
        {
            return;
        }
        ExecuteAction(parameter);
    }

    public Action<object> ExecuteAction { get; set; }
    public Func<object,bool> CanExecuteFunc { get; set; }//接受一个object参数，返回一个bool类型参数
}

class MainWindowViewModel:NotificationObject
{
    private double input1;

    public double Input1
        {
            get { return input1; }
            set
            {
                input1 = value;
                this.RaisePropertyChanged("Input1");
            }
        }

    private double input2;

    public double Input2
        {
            get { return input2; }
            set
            {
                input2 = value;
                this.RaisePropertyChanged("Input2");
            }
        }

    private double result;

    public double Result
        {
            get { return result; }
            set
            {
                result = value;
                this.RaisePropertyChanged("Result");
            }
        }

    public DelegateCommand AddCommand { get; set; }
    private void Add(object prop)
        {
            Result = Input1 + Input2;
        }

    public DelegateCommand SaveCommand { get; set; }
    private void Save(object prop)
        {
            SaveFileDialog dlg = new SaveFileDialog();
            dlg.ShowDialog();
        }

    public MainWindowViewModel()
        {//将命令的方法与委托命令属性关联起来
            AddCommand = new DelegateCommand();
            AddCommand.ExecuteAction = new Action<object>(Add);
            SaveCommand = new DelegateCommand();
            SaveCommand.ExecuteAction = new Action<object>(Save);
        }

}

<Window x:Class="SimpleMvvmDemoClient.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:SimpleMvvmDemoClient"
        mc:Ignorable="d"
        Title="MainWindow" Height="300" Width="300">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="30"/>
            <RowDefinition Height="20*"/>
            <RowDefinition Height="20*"/>
            <RowDefinition Height="20*"/>
            <RowDefinition Height="20*"/>
        </Grid.RowDefinitions>
        <Button Content="Save" Grid.Row="0" Command="{Binding SaveCommand}"/>
        <TextBox Grid.Row="1" Text="{Binding Input1}" Margin="10" Background="AliceBlue" TextAlignment="Center" FontSize="30"/>
        <TextBox Grid.Row="2" Text="{Binding Input2}" Margin="10" Background="AliceBlue" TextAlignment="Center" FontSize="30"/>
        <TextBox Grid.Row="3" Text="{Binding Result}" Margin="10" Background="AliceBlue" TextAlignment="Center" FontSize="30"/>
        <Button Content="Add" Grid.Row="4" Margin="10" Command="{Binding AddCommand}"/>
    </Grid>
</Window>

UI的后台代码只有一句话：this.DataContext = new MainWindowViewModel();     即可