引用地址:http://blog.csdn.net/yl2isoft/article/details/20838149
1新建WPF应用程序WPFMVVMExample
程序结构如下图所示。
2Model实现
在Model文件夹下新建业务类StudentModel(类文件StudentModel.cs),类的详细代码如下所示。
- usingSystem.ComponentModel;
- namespaceWPFMVVMExample.Model
- {
- publicclassStudentModel:INotifyPropertyChanged
- {
- ///<summary>
- ///学号
- ///</summary>
- privateintstudentId;
- publicintStudentId
- {
- get
- {
- returnstudentId;
- }
- set
- {
- studentId=value;
- NotifyPropertyChanged("StudentId");
- }
- }
- ///<summary>
- ///姓名
- ///</summary>
- privatestringstudentName;
- publicstringStudentName
- {
- get
- {
- returnstudentName;
- }
- set
- {
- studentName=value;
- NotifyPropertyChanged("StudentName");
- }
- }
- ///<summary>
- ///年龄
- ///</summary>
- privateintstudentAge;
- publicintStudentAge
- {
- get
- {
- returnstudentAge;
- }
- set
- {
- studentAge=value;
- NotifyPropertyChanged("StudentAge");
- }
- }
- ///<summary>
- ///</summary>
- privatestringstudentEmail;
- publicstringStudentEmail
- {
- get
- {
- returnstudentEmail;
- }
- set
- {
- studentEmail=value;
- NotifyPropertyChanged("StudentEmail");
- }
- }
- ///<summary>
- ///性别
- ///</summary>
- privatestringstudentSex;
- publicstringStudentSex
- {
- get
- {
- returnstudentSex;
- }
- set
- {
- studentSex=value;
- NotifyPropertyChanged("StudentSex");
- }
- }
- publiceventPropertyChangedEventHandlerPropertyChanged;
- publicvoidNotifyPropertyChanged(stringpropertyName)
- {
- if(PropertyChanged!=null)
- {
- PropertyChanged(this,newPropertyChangedEventArgs(propertyName));
- }
- }
- }
- }
StudentModel类实现了接口INotifyPropertyChanged。当类实现该接口后,便可以向执行绑定的客户端发出某一属性值已更改的通知。
3ViewModel实现
在ViewModel文件夹下新建类文件StudentViewModel.cs,类文件的详细代码如下所示。
- usingSystem;
- usingSystem.Windows.Input;
- usingWPFMVVMExample.Model;
- namespaceWPFMVVMExample.ViewModel
- {
- publicclassStudentViewModel
- {
- publicDelegateCommandShowCommand{get;set;}
- publicStudentModelStudent{get;set;}
- publicStudentViewModel()
- {
- Student=newStudentModel();
- ShowCommand=newDelegateCommand();
- ShowCommand.ExecuteCommand=newAction<object>(ShowStudentData);
- }
- privatevoidShowStudentData(objectobj)
- {
- Student.StudentId=1;
- Student.StudentName="tiana";
- Student.StudentAge=20;
- Student.StudentEmail="8644003248@qq.com";
- Student.StudentSex="大帅哥";
- }
- }
- publicclassDelegateCommand:ICommand
- {
- publicAction<object>ExecuteCommand=null;
- publicFunc<object,bool>CanExecuteCommand=null;
- publiceventEventHandlerCanExecuteChanged;
- publicboolCanExecute(objectparameter)
- {
- if(CanExecuteCommand!=null)
- {
- returnthis.CanExecuteCommand(parameter);
- }
- else
- {
- returntrue;
- }
- }
- publicvoidExecute(objectparameter)
- {
- if(this.ExecuteCommand!=null)
- {
- this.ExecuteCommand(parameter);
- }
- }
- publicvoidRaiseCanExecuteChanged()
- {
- if(CanExecuteChanged!=null)
- {
- CanExecuteChanged(this,EventArgs.Empty);
- }
- }
- }
- }
代码中,除了定义StudentViewModel类外,还定义了DelegateCommand类,该类实现了ICommand接口。
ICommand接口中的Execute()方法用于命令的执行,CanExecute()方法用于指示当前命令在目标元素上是否可用,当这种可用性发生改变时便会触发接口中的CanExecuteChanged事件。
我们可以将实现了ICommand接口的命令DelegateCommand赋值给Button(命令源)的Command属性(只有实现了ICommandSource接口的元素才拥有该属性),这样Button便与命令进行了绑定。
4MainWindow.xaml实现
MainWindow.xaml的界面如下图所示。
MainWindow.xaml界面的xaml代码如下所示。
- <Windowx:Class="WPFMVVMExample.MainWindow"
- xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
- xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
- Title="MainWindow"Height="350"Width="525">
- <Grid>
- <LabelContent="学号"Height="28"HorizontalAlignment="Left"Margin="54,23,0,0"Name="labelStudentId"VerticalAlignment="Top"/>
- <TextBoxText="{BindingStudent.StudentId}"IsReadOnly="True"Height="23"HorizontalAlignment="Right"Margin="0,27,289,0"Name="textBoxStudentId"VerticalAlignment="Top"Width="120"/>
- <LabelContent="姓名"Height="28"HorizontalAlignment="Left"Margin="54,61,0,0"Name="labelStudentName"VerticalAlignment="Top"/>
- <TextBoxText="{BindingStudent.StudentName}"IsReadOnly="True"Height="23"HorizontalAlignment="Left"Margin="94,65,0,0"Name="textBoxStudentName"VerticalAlignment="Top"Width="120"/>
- <LabelContent="年龄"Height="28"HorizontalAlignment="Left"Margin="54,94,0,0"Name="labelStudentAge"VerticalAlignment="Top"/>
- <TextBoxText="{BindingStudent.StudentAge}"IsReadOnly="True"Height="23"HorizontalAlignment="Left"Margin="94,99,0,0"Name="textBoxStudentAge"VerticalAlignment="Top"Width="120"/>
- <LabelContent="Email"Height="28"HorizontalAlignment="Left"Margin="50,138,0,0"Name="labelStudentEmail"VerticalAlignment="Top"/>
- <TextBoxText="{BindingStudent.StudentEmail}"IsReadOnly="True"Height="23"HorizontalAlignment="Left"Margin="94,141,0,0"Name="textBoxStudentEmail"VerticalAlignment="Top"Width="120"/>
- <LabelContent="性别"Height="28"HorizontalAlignment="Left"Margin="57,176,0,0"Name="labelStudentSex"VerticalAlignment="Top"/>
- <TextBoxText="{BindingStudent.StudentSex}"IsReadOnly="True"Height="23"HorizontalAlignment="Left"Margin="94,180,0,0"Name="textBoxStudentSex"VerticalAlignment="Top"Width="120"/>
- <ButtonCommand="{BindingShowCommand}"Content="显示"Height="23"HorizontalAlignment="Left"Margin="345,27,0,0"Name="buttonShow"VerticalAlignment="Top"Width="75"/>
- </Grid>
- </Window>
MainWindow.xaml的后端代码如下所示。
- usingSystem.Windows;
- usingWPFMVVMExample.ViewModel;
- namespaceWPFMVVMExample
- {
- ///<summary>
- ///MainWindow.xaml的交互逻辑
- ///</summary>
- publicpartialclassMainWindow:Window
- {
- publicMainWindow()
- {
- InitializeComponent();
- this.DataContext=newStudentViewModel();
- }
- }
- }
5运行程序
运行程序,点击“显示”按钮,即将数据绑定至界面显示。
6说明
WPF中使用MVVM可以降低UI显示与后端逻辑代码的耦合度,即更换界面时,只需要修改很少的逻辑代码就可以实现,甚至不用修改。
在WinForm开发中,我们一般会直接操作界面的元素(如:TextBox1.Text=“aaa”),这样一来,界面变化后,后端逻辑代码也需要做相应的变更。
在WPF中使用数据绑定机制,当数据变化后,数据会通知界面变更的发生,而不需要通过访问界面元素来修改值,这样在后端逻辑代码中也就不必操作或者很少操作界面的元素了。
使用MVVM,可以很好的配合WPF的数据绑定机制来实现UI与逻辑代码的分离,MVVM中的View表示界面,负责页面显示,ViewModel负责逻辑处理,包括准备绑定的数据和命令,ViewModel通过View的DataContext属性绑定至View,Model为业务模型,供ViewModel使用。