Version:1.0StartHTML:000000209EndHTML:000041669StartFragment:000013042EndFragment:000041595StartSelection:000013064EndSelection:000041579SourceURL:https://www.cnblogs.com/bwlluck/p/7011029.html
引用地址：http://blog.csdn.net/yl2isoft/article/details/20838149
1?新建WPF?應(yīng)用程序WPFMVVMExample
程序結(jié)構(gòu)如下圖所示。
2?Model實現(xiàn)
在Model文件夾下新建業(yè)務(wù)類StudentModel（類文件StudentModel.cs），類的詳細(xì)代碼如下所示。
[csharp]view plaincopy
using?System.ComponentModel;??
namespace?WPFMVVMExample.Model??
{??
publicclass?StudentModel?:?INotifyPropertyChanged??
????{??
///?<summary>??
///?學(xué)號??
///?</summary>??
privateint?studentId;??
publicint?StudentId??
????????{??
get???
????????????{???
return?studentId;???
????????????}??
set???
????????????{???
????????????????studentId?=?value;??
NotifyPropertyChanged("StudentId");??
????????????}??
????????}??
///?<summary>??
///?姓名??
///?</summary>??
privatestring?studentName;??
publicstring?StudentName??
????????{??
get???
????????????{???
return?studentName;???
????????????}??
set???
????????????{???
????????????????studentName?=?value;??
NotifyPropertyChanged("StudentName");??
????????????}??
????????}??
///?<summary>??
///?年齡??
///?</summary>??
privateint?studentAge;??
publicint?StudentAge??
????????{??
get???
????????????{???
return?studentAge;???
????????????}??
set???
????????????{???
????????????????studentAge?=?value;??
NotifyPropertyChanged("StudentAge");??
????????????}??
????????}??
///?<summary>??
///?Email??
///?</summary>??
privatestring?studentEmail;??
publicstring?StudentEmail??
????????{??
get???
????????????{???
return?studentEmail;???
????????????}??
set???
????????????{???
????????????????studentEmail?=?value;??
NotifyPropertyChanged("StudentEmail");??
????????????}??
????????}??
///?<summary>??
///?性別??
///?</summary>??
privatestring?studentSex;??
publicstring?StudentSex??
????????{??
get???
????????????{???
return?studentSex;???
????????????}??
set???
????????????{???
????????????????studentSex?=?value;??
NotifyPropertyChanged("StudentSex");??
????????????}??
????????}??
publicevent?PropertyChangedEventHandler?PropertyChanged;??
publicvoid?NotifyPropertyChanged(string?propertyName)??
????????{??
if?(PropertyChanged?!=null)??
????????????{??
PropertyChanged(this,new?PropertyChangedEventArgs(propertyName));??
????????????}??
????????}??
????}??
}??
StudentModel類實現(xiàn)了接口INotifyPropertyChanged。當(dāng)類實現(xiàn)該接口后，便可以向執(zhí)行綁定的客戶端發(fā)出某一屬性值已更改的通知。
3?ViewModel實現(xiàn)
在ViewModel文件夾下新建類文件StudentViewModel.cs,類文件的詳細(xì)代碼如下所示。
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using?System;??
using?System.Windows.Input;??
using?WPFMVVMExample.Model;??
namespace?WPFMVVMExample.ViewModel??
{??
publicclass?StudentViewModel??
????{??
public?DelegateCommand?ShowCommand?{get;set;?}??
public?StudentModel?Student?{get;set;?}??
public?StudentViewModel()??
????????{??
Student?=new?StudentModel();??
ShowCommand=new?DelegateCommand();??
ShowCommand.ExecuteCommand?=new?Action
????????}??
privatevoid?ShowStudentData(object?obj)??
????????{??
????????????Student.StudentId?=?1;??
Student.StudentName?="tiana";??
????????????Student.StudentAge?=?20;??
Student.StudentEmail?="8644003248@qq.com";??
Student.StudentSex?="大帥哥";??
????????}??
????}??
publicclass?DelegateCommand?:?ICommand??
????{??
public?Action?ExecuteCommand?=null;??
public?Func?CanExecuteCommand?=null;??
publicevent?EventHandler?CanExecuteChanged;??
publicbool?CanExecute(object?parameter)??
????????{??
if?(CanExecuteCommand?!=null)??
????????????{??
returnthis.CanExecuteCommand(parameter);??
????????????}??
else??
????????????{??
returntrue;??
????????????}??
????????}??
publicvoid?Execute(object?parameter)??
????????{??
if?(this.ExecuteCommand?!=null)??
????????????{???
this.ExecuteCommand(parameter);???
????????????}??
????????}??
publicvoid?RaiseCanExecuteChanged()??
????????{??
if?(CanExecuteChanged?!=null)??
????????????{??
CanExecuteChanged(this,?EventArgs.Empty);??
????????????}??
????????}??
????}??
}??
代碼中，除了定義StudentViewModel類外，還定義了DelegateCommand類，該類實現(xiàn)了ICommand接口。
ICommand接口中的Execute（）方法用于命令的執(zhí)行，CanExecute（）方法用于指示當(dāng)前命令在目標(biāo)元素上是否可用，當(dāng)這種可用性發(fā)生改變時便會觸發(fā)接口中的CanExecuteChanged事件。
我們可以將實現(xiàn)了ICommand接口的命令DelegateCommand賦值給Button（命令源）的Command屬性（只有實現(xiàn)了ICommandSource接口的元素才擁有該屬性），這樣Button便與命令進(jìn)行了綁定。
4?MainWindow.xaml實現(xiàn)
MainWindow.xaml的界面如下圖所示。
MainWindow.xaml界面的xaml代碼如下所示。
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xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"??
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"??
Title="MainWindow"Height="350"Width="525">??
MainWindow.xaml的后端代碼如下所示。
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using?System.Windows;??
using?WPFMVVMExample.ViewModel;??
namespace?WPFMVVMExample??
{??
///?<summary>??
///?MainWindow.xaml?的交互邏輯??
///?</summary>??
public?partialclass?MainWindow?:?Window??
????{??
public?MainWindow()??
????????{??
????????????InitializeComponent();??
this.DataContext?=new?StudentViewModel();??
????????}??
????}??
}??
5?運(yùn)行程序
運(yùn)行程序，點擊“顯示”按鈕，即將數(shù)據(jù)綁定至界面顯示。
6?說明
WPF中使用MVVM可以降低UI顯示與后端邏輯代碼的耦合度，即更換界面時，只需要修改很少的邏輯代碼就可以實現(xiàn)，甚至不用修改。
在WinForm開發(fā)中，我們一般會直接操作界面的元素（如：TextBox1.Text=“aaa”），這樣一來，界面變化后，后端邏輯代碼也需要做相應(yīng)的變更。
在WPF中使用數(shù)據(jù)綁定機(jī)制，當(dāng)數(shù)據(jù)變化后，數(shù)據(jù)會通知界面變更的發(fā)生，而不需要通過訪問界面元素來修改值，這樣在后端邏輯代碼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的數(shù)據(jù)綁定機(jī)制來實現(xiàn)UI與邏輯代碼的分離，MVVM中的View表示界面，負(fù)責(zé)頁面顯示，ViewModel負(fù)責(zé)邏輯處理，包括準(zhǔn)備綁定的數(shù)據(jù)和命令，ViewModel通過View的DataContext屬性綁定至View，Model為業(yè)務(wù)模型，供ViewModel使用。
