WPF Event 在 Command 中的应用初级篇，支持所有Event 展示松耦合设计的全部代码 - 解决TextBoxBase.TextChanged或者TextBox.TextChanged等类似事件绑定问题。
做过WPF开发的人，都知道做MVVM架构，最麻烦的是Event的绑定，因为Event是不能被绑定的，同时现有的条件下，命令是无法替代Event。而在开发过程中无法避免Event事件，这样MVVM的架构就不能完全实现了。
所以后来微软提供了一个折中的方案，使用Trigger触发器和System.Windows.Interactivity结合通过事件绑定事件，个人觉得这个方法也挺可以的。
还有Prism框架方法，我看过但是这个方法比较繁琐可用性不高。
后来通过搜索和自己研究知道了一个解决方案，可以绑定所有事件，这个是原始版本，我个人正在研究一个完全的版本，希望能完全支持Event属性。
对于编程学习喜欢的方式，我个人是这个看法，我做开发也有一年多了，WPF开发也有九个月了。从小白到现在入门略有深入。不再局限于实现效果，而是更喜欢实现功能的原汁原味的代码。很多效果也许我不能写出完整的代码，也没有那么多的时间，但是深入看了别人的设计代码，总是受益良多。
工作这么长时间，总算明白为什么Java那么受欢迎了。因为作为技术人员到了一定境界，更喜欢了解具体的实现过程，而对于直接使用SDK的兴趣淡了不少。打个比方微软提供了很多优秀的SDK,但是就像家庭一样，越是包办一切的好父母，往往不太招孩子们的喜欢，不是孩子们不懂得感恩，而是社会自然规律，你无法成长，你便很容易感觉到自己无能，无能的人哪有快乐而言。
正文：具体的类图 通过类图可以看到结构相当清晰，它们的依赖关系是单向的。是属于低耦合的关系
现在提供各个类的代码，从上到下，层次从左到右。注意实际上建立类的顺序是相反的，这里只是为了展示方便
Events.cs
using System; using System.Windows; using System.Windows.Controls; using System.Windows.Data; namespace ManMonthMyth.Practices.Composite.Presentation.Behaviors { /// <summary> /// 这个类的作用是真正的绑定命令 /// 将命令绑定到对应的控件上 /// </summary> public class Events { /// <summary> /// 事件行为属性 /// 注册属性名 /// </summary> private static readonly DependencyProperty EventBehaviorsProperty = DependencyProperty.RegisterAttached("EventBehaviors",typeof(EventBehaviorCollection),typeof(Control),null); private static readonly DependencyProperty InternalDataContextProperty = DependencyProperty.RegisterAttached("InternalDataContext", typeof(Object), typeof(Control), new PropertyMetadata(null, DataContextChanged)); public static readonly DependencyProperty CommandsProperty = DependencyProperty.RegisterAttached("Commands", typeof(EventCommandCollection), typeof(Events), new PropertyMetadata(null, CommandsChanged)); private static void DataContextChanged(DependencyObject dependencyObject,DependencyPropertyChangedEventArgs e) { var target = dependencyObject as Control; if (target == null) return; foreach (var behavior in GetOrCreateBehavior(target)) { behavior.Bind(); } } public static EventCommandCollection GetCommands(DependencyObject dependencyObject) { return dependencyObject.GetValue(CommandsProperty) as EventCommandCollection; } public static void SetCommands(DependencyObject dependencyObject,EventCommandCollection eventCommands) { dependencyObject.SetValue(CommandsProperty,eventCommands); } private static void CommandsChanged(DependencyObject dependencyObject,DependencyPropertyChangedEventArgs e) { var target = dependencyObject as Control; if (target == null) return; var behaviors = GetOrCreateBehavior(target); foreach (var eventCommand in e.NewValue as EventCommandCollection) { var behavior = new EventBehavior(target); behavior.Bind(eventCommand); behaviors.Add(behavior); } } private static EventBehaviorCollection GetOrCreateBehavior(FrameworkElement target) { var behavior = target.GetValue(EventBehaviorsProperty) as EventBehaviorCollection; if (behavior == null) { behavior = new EventBehaviorCollection(); target.SetValue(EventBehaviorsProperty,behavior); target.SetBinding(InternalDataContextProperty,new Binding()); } return behavior; } } }
EventBehaviorCollection
using System; using System.Collections.Generic; namespace ManMonthMyth.Practices.Composite.Presentation.Behaviors { /// <summary> /// 事件名称集合 /// </summary> public class EventCommandCollection : List<EventCommand> { } }
EventBehavior
using System; using System.ComponentModel; using System.Reflection; using System.Windows; using System.Windows.Controls; using System.Windows.Input; using System.Windows.Media; namespace ManMonthMyth.Practices.Composite.Presentation.Behaviors { /// <summary> /// 事件行为 /// 这个类的作用是将，通过反射将事件名，实例化一个真正的事件对象 /// </summary> public class EventBehavior : CommandBehaviorBase<Control> { private EventCommand _bindingInfo; public EventBehavior(Control control) : base(control) { } public void Bind(EventCommand bindingInfo) { ValidateBindingInfo(bindingInfo); _bindingInfo = bindingInfo; Bind(); } private void ValidateBindingInfo(EventCommand bindingInfo) { if (bindingInfo == null) throw new ArgumentException("bindingInfo is Null"); if (string.IsNullOrEmpty(bindingInfo.CommandName)) throw new ArgumentException("bindingInfo.CommandName is Null"); if (string.IsNullOrEmpty(bindingInfo.EventName)) throw new ArgumentException("bindingInfo.EventName is Null"); } public void Bind() { ValidateBindingInfo(_bindingInfo); HookPropertyChanged(); HookEvent(); SetCommand(); } public void HookPropertyChanged() { var dataContext = this.TargetObject.DataContext as INotifyPropertyChanged; if (dataContext == null) return; dataContext.PropertyChanged -= this.DataContextPropertyChanged; dataContext.PropertyChanged += this.DataContextPropertyChanged; } private void DataContextPropertyChanged(object sender,PropertyChangedEventArgs e) { if (e.PropertyName == _bindingInfo.CommandName) this.SetCommand(); } private void SetCommand() { var dataContext = this.TargetObject.DataContext; if (dataContext == null) return; var propertyInfo = dataContext.GetType().GetProperty(_bindingInfo.CommandName); if (propertyInfo == null) throw new ArgumentException("propertyInfo is null,commandName is error"); this.Command = propertyInfo.GetValue(dataContext,null) as ICommand; } /// <summary> /// 钩事件 /// 有助于绑定AttachedProperty属性 /// </summary> private void HookEvent() { var eventNames = _bindingInfo.EventName.Split('.'); int length = eventNames.Length; //分开来，目的是为了提高效率 if (length == 1) { var eventInfo = this.TargetObject.GetType().GetEvent(_bindingInfo.EventName, BindingFlags.Public | BindingFlags.Instance); if (eventInfo == null) throw new ArgumentException("eventInfo is Null,eventName is error"); eventInfo.RemoveEventHandler(this.TargetObject, this.GetEventMethod(eventInfo)); eventInfo.AddEventHandler(this.TargetObject, GetEventMethod(eventInfo)); } else { //TargetObject控件加载完成后触发执行 this.TargetObject.Initialized += (sender, e) => { var tempObject = SelectVisual(eventNames, this.TargetObject); var tempEventInfo = tempObject.GetType().GetEvent(eventNames[length-1], BindingFlags.Public | BindingFlags.Instance); if (tempEventInfo == null) throw new ArgumentException("eventInfo is Null,eventName is error"); tempEventInfo.RemoveEventHandler(tempObject, this.GetEventMethod(tempEventInfo)); tempEventInfo.AddEventHandler(tempObject, GetEventMethod(tempEventInfo)); }; } } #region 筛选内部控件 /// <summary> /// 筛选Visual /// </summary> /// <param name="names"></param> /// <param name="obj"></param> /// <returns></returns> private static Visual SelectVisual(string[] names, Control obj) { var assemblies = AppDomain.CurrentDomain.GetAssemblies(); int act = assemblies.Length; for (int i = 0; i < act; i++) { if (assemblies[i].FullName.Split(',')[0] == "PresentationFramework") { return SelectVisual(assemblies[i], names, 0, obj); } } return null; } /// <summary> /// 命名空间名称集合 /// </summary> static string[] namespaceNames = {"System.Windows.Controls.Primitives","System.Windows.Controls" }; /// <summary> /// 筛选Visual /// </summary> /// <param name="assembly"></param> /// <param name="names"></param> /// <param name="i"></param> /// <param name="obj"></param> /// <returns></returns> private static Visual SelectVisual(Assembly assembly, string[] names,int i,Visual obj) { Type type=null; int tempLength=namespaceNames.Length; for (int j = 0; j < tempLength; j++) { type = assembly.GetType(string.Format("{0}.{1}",namespaceNames[j], names[i])); if(type!=null) { break; } } if (type == null) { return null; } obj = GetDescendantByType(obj, type); if (names.Length == (i+2))//判断是否到了数组有效的位置,因为为了偷懒没有对string[]进行去尾操作，因为string[]最后一个数据是事件名称,在这里是 无效的 { return obj; } return SelectVisual(assembly, names, i+1, obj); } /// <summary> /// 通过Type获取包含的控件 /// </summary> /// <param name="element"></param> /// <param name="type"></param> /// <returns></returns> private static Visual GetDescendantByType(Visual element, Type type) { if (element == null) return null; if (element.GetType() == type||element.GetType().BaseType==type) return element; Visual foundElement = null; if (element is FrameworkElement) (element as FrameworkElement).ApplyTemplate(); int cnt = VisualTreeHelper.GetChildrenCount(element); for (int i = 0; i < cnt; i++) { Visual visual = VisualTreeHelper.GetChild(element, i) as Visual; foundElement = GetDescendantByType(visual, type); if (foundElement != null) break; } return foundElement; } #endregion private Delegate _method; private Delegate GetEventMethod(EventInfo eventInfo) { if (eventInfo == null) throw new ArgumentException("eventInfo is null"); if (eventInfo.EventHandlerType == null) throw new ArgumentException("EventHandlerType is null"); if (this._method == null) { this._method = Delegate.CreateDelegate( eventInfo.EventHandlerType,this,GetType().GetMethod("OnEventRaised",BindingFlags.NonPublic|BindingFlags.Instance)); } return _method; } private void OnEventRaised(object sender,EventArgs e) { this.ExecuteCommand(); } } }
EventCommandCollection
using System; using System.Collections.Generic; namespace ManMonthMyth.Practices.Composite.Presentation.Behaviors { /// <summary> /// 事件名称集合 /// </summary> public class EventCommandCollection : List<EventCommand> { } }
CommandBehaviorBase
using System; using System.Windows.Controls; using System.Windows.Input; namespace ManMonthMyth.Practices.Composite.Presentation.Behaviors { /// <summary> /// 基于行为的处理连接的一个命令 /// 这个类可以用来提供新的行为，比如按钮的Clik事件行为 /// 鼠标进入控件的事件行为 /// </summary> /// <typeparam name="T"></typeparam> public class CommandBehaviorBase<T> where T : Control { /// <summary> /// 定义的一个命令 /// </summary> private ICommand command; /// <summary> /// 命令传值的内容 /// </summary> private object commandParameter; /// <summary> /// 弱引用对象 /// 即对象被引用的情况下,允许垃圾回收来回收对象 /// </summary> private readonly WeakReference targetObject; /// <summary> /// 命令中允许事件发生的事件的方法， /// 即允许事件发生的条件 /// </summary> private readonly EventHandler commandCanExecuteChangedHandler; #region 属性 /// <summary> /// 相应的命令被执行和监控 /// </summary> public ICommand Command { get { return this.command; } set { if (this.command != null) { this.command.CanExecuteChanged -= this.commandCanExecuteChangedHandler; } this.command = value; if (this.command != null) { this.command.CanExecuteChanged += this.commandCanExecuteChangedHandler; this.UpdateEnabledState(); } } } /// <summary> /// 命令中传值的内容 /// </summary> public object CommandParameter { get { return this.commandParameter; } set { if (this.commandParameter != value) { this.commandParameter = value; this.UpdateEnabledState(); } } } /// <summary> /// 一个弱引用的对象 /// </summary> protected T TargetObject { get { return targetObject.Target as T; } } #endregion /// <summary> /// 构造函数 /// </summary> /// <param name="targetObject">行为上的目标对象</param> public CommandBehaviorBase(T targetObject) { this.targetObject = new WeakReference(targetObject); this.commandCanExecuteChangedHandler = new EventHandler(this.CommandCanExecuteChanged); } /// <summary> /// /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void CommandCanExecuteChanged(object sender,EventArgs e) { this.UpdateEnabledState(); } /// <summary> /// 基于属性的命令的执行，来更新的目标对象。 /// </summary> protected virtual void UpdateEnabledState() { if (this.TargetObject == null) { this.Command = null; this.CommandParameter = null; }else if(this.Command!=null) { this.TargetObject.IsEnabled = this.Command.CanExecute(this.CommandParameter); } } /// <summary> /// 执行命令 /// </summary> protected virtual void ExecuteCommand() { if (this.Command != null) { this.Command.Execute(this.CommandParameter); } } } }
EventCommand
using System; namespace ManMonthMyth.Practices.Composite.Presentation.Behaviors { public class EventCommand { /// <summary> /// 命令名称 /// 这个可以自定义，比如myCommandClick等 /// </summary> public string CommandName { get; set; } /// <summary> /// 特定的事件名称 /// 首先要确认绑定的控件支持这个事件 /// 比如Click MouseOver 等 /// </summary> public string EventName { get; set; } } }
现在完整的框架已经搭建好了，现在就是做一个Demo就可以了。
用命令绑定事件，就要考虑到类似TextBoxBase.TextChanged命令的问题，理解这个的前提是了解Attached Property，Attached Property是DependencyObject的一种特殊形式，它利用DependencyProperty.RegisterAttached方法注册的。可以被有效的添加到任何继承自DependencyObject的对象中。同时要明白绑定控件中包含有TextBox这个控件,找到TextBox控件然后绑定它的事件问题就解决了。
说完思路现在提供以上绑事件命令类库如何使用：
<ComboBox x:Name="cboBox" Margin="115,0,10,0" IsEditable="True" ItemsSource="{Binding ListCollection}" Text="{Binding UserName,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" FontSize="15" Height="25" HorizontalAlignment="Left" VerticalAlignment="Center" Width="179"> <Behaviors:Events.Commands> <Behaviors:EventCommandCollection> <!--<Behaviors:EventCommand CommandName="cboTextBoxChangedCommand" EventName="TextBox.TextChanged" />--> <Behaviors:EventCommand CommandName="cboTextBoxBaseChangedCommand" EventName="TextBoxBase.TextChanged" /> <Behaviors:EventCommand CommandName="cboSelectionChangedCommand" EventName="SelectionChanged" /> </Behaviors:EventCommandCollection> </Behaviors:Events.Commands> </ComboBox>
运用示例代码来自于这个xaml文件中
MainWindow.xaml
<Window x:Class="EventCommandDemo.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:EventCommandDemo" xmlns:Behaviors="clr-namespace:ManMonthMyth.Practices.Composite.Presentation.Behaviors;assembly=ManMonthMyth.Practices.Composite.Presentation.Behaviors" Title="MainWindow" Width="400" Height="300" WindowStyle="None" ResizeMode="NoResize" Background="LightPink" WindowStartupLocation="CenterScreen"> <Window.Triggers> <EventTrigger SourceName="chkRememberPwd" RoutedEvent="CheckBox.Unchecked"> <BeginStoryboard> <Storyboard> <BooleanAnimationUsingKeyFrames Storyboard.TargetName="chkLanding" Storyboard.TargetProperty="IsChecked"> <DiscreteBooleanKeyFrame KeyTime="0:0:0.01" Value="False" /> </BooleanAnimationUsingKeyFrames> </Storyboard> </BeginStoryboard> </EventTrigger> <EventTrigger SourceName="chkLanding" RoutedEvent="CheckBox.Checked"> <BeginStoryboard> <Storyboard> <BooleanAnimationUsingKeyFrames Storyboard.TargetName="chkRememberPwd" Storyboard.TargetProperty="IsChecked"> <DiscreteBooleanKeyFrame KeyTime="0:0:0.01" Value="True" /> </BooleanAnimationUsingKeyFrames> </Storyboard> </BeginStoryboard> </EventTrigger> </Window.Triggers> <Viewbox> <Grid Width="400" Height="300"> <Grid.RowDefinitions> <RowDefinition Height="120" /> <RowDefinition Height="40" /> <RowDefinition Height="40" /> <RowDefinition Height="30" /> <RowDefinition /> </Grid.RowDefinitions> <StackPanel Grid.Row="1" Orientation="Horizontal"> <ComboBox x:Name="cboBox" Margin="115,0,10,0" IsEditable="True" ItemsSource="{Binding ListCollection}" Text="{Binding UserName,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" FontSize="15" Height="25" HorizontalAlignment="Left" VerticalAlignment="Center" Width="179"> <Behaviors:Events.Commands> <Behaviors:EventCommandCollection> <!--<Behaviors:EventCommand CommandName="cboTextBoxChangedCommand" EventName="TextBox.TextChanged" />--> <Behaviors:EventCommand CommandName="cboTextBoxBaseChangedCommand" EventName="TextBoxBase.TextChanged" /> <Behaviors:EventCommand CommandName="cboSelectionChangedCommand" EventName="SelectionChanged" /> </Behaviors:EventCommandCollection> </Behaviors:Events.Commands> </ComboBox> <TextBlock HorizontalAlignment="Left" VerticalAlignment="Center" Text="注册账号" > <Behaviors:Events.Commands> <Behaviors:EventCommandCollection> <Behaviors:EventCommand CommandName="TxTMouseEnterCommand" EventName="MouseEnter" /> </Behaviors:EventCommandCollection> </Behaviors:Events.Commands> </TextBlock> </StackPanel> <StackPanel Grid.Row="2" Orientation="Horizontal"> <PasswordBox Margin="115,0,10,0" local:PasswordBoxBindingHelper.IsPasswordBindingEnabled="True" local:PasswordBoxBindingHelper.BindedPassword="{Binding Path=UserPassword,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" FontSize="15" Height="25" HorizontalAlignment="Left" VerticalAlignment="Center" Width="179" > <Behaviors:Events.Commands> <Behaviors:EventCommandCollection> <Behaviors:EventCommand CommandName="pwdGotFocusCommand" EventName="GotFocus" /> </Behaviors:EventCommandCollection> </Behaviors:Events.Commands> </PasswordBox> <TextBlock HorizontalAlignment="Left" VerticalAlignment="Center" Name="textBlock2" Text="忘记密码" Style="{Binding ElementName=textBlock1,Path=Style}" /> </StackPanel> <StackPanel Grid.Row="3" Orientation="Horizontal"> <CheckBox x:Name="chkRememberPwd" Content="记住密码" IsThreeState="False" HorizontalAlignment="Left" Margin="115,0,0,0" VerticalAlignment="Top" > <Behaviors:Events.Commands> <Behaviors:EventCommandCollection> <Behaviors:EventCommand CommandName="chkUncheckedCommand" EventName="Unchecked"/> <Behaviors:EventCommand CommandName="chkCheckedCommand" EventName="Checked" /> </Behaviors:EventCommandCollection> </Behaviors:Events.Commands> </CheckBox> <CheckBox x:Name="chkLanding" Content="自动登陆" IsThreeState="False" HorizontalAlignment="Left" Margin="15,0,0,0" VerticalAlignment="Top" /> </StackPanel> <StackPanel Grid.Row="4" Orientation="Horizontal"> <Button Margin="120,0,0,0" Height="33" Width="181" Name="btnLogin" VerticalAlignment="Top"> <TextBlock FontSize="18" FontFamily="Consolas;Microsoft YaHei" Foreground="Blue" Text="登 录" /> <Behaviors:Events.Commands> <Behaviors:EventCommandCollection> <!--<Behaviors:EventCommand CommandName="btnMouseDoubleClickCommand" EventName="MouseDoubleClick" />--> <Behaviors:EventCommand CommandName="btnClickCommand" EventName="Click" /> </Behaviors:EventCommandCollection> </Behaviors:Events.Commands> </Button> </StackPanel> </Grid> </Viewbox> </Window>
运行后的界面
MainWindow.xaml 后台代码 MainWindow.cs
using System; using System.Collections.Generic; using System.Linq; using System.Reflection; 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.Navigation; using System.Windows.Shapes; namespace EventCommandDemo { /// <summary> /// MainWindow.xaml 的交互逻辑 /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); #region 绑定数据和命令 MainViewModel _viewmodel = null; this.Loaded += (sender, e) => { if (_viewmodel == null) { _viewmodel = new MainViewModel(); this.DataContext = _viewmodel; } }; #endregion } } }
Mainwindow.xaml辅助类 PasswordBoxBindingHelper.cs，提供PasswordBox绑定属性
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; namespace EventCommandDemo { public static class PasswordBoxBindingHelper { public static bool GetIsPasswordBindingEnabled(DependencyObject obj) { return (bool)obj.GetValue(IsPasswordBindingEnabledProperty); } public static void SetIsPasswordBindingEnabled(DependencyObject obj, bool value) { obj.SetValue(IsPasswordBindingEnabledProperty, value); } public static readonly DependencyProperty IsPasswordBindingEnabledProperty = DependencyProperty.RegisterAttached("IsPasswordBindingEnabled", typeof(bool), typeof(PasswordBoxBindingHelper),new UIPropertyMetadata(false,OnIsPasswordBindingEnabledChanged)); private static void OnIsPasswordBindingEnabledChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e) { var passwordBox = obj as System.Windows.Controls.PasswordBox; if (passwordBox != null) { passwordBox.PasswordChanged -= PasswordBoxPasswordChanged; if ((bool)e.NewValue) { passwordBox.PasswordChanged += PasswordBoxPasswordChanged; } } } static void PasswordBoxPasswordChanged(object sender, RoutedEventArgs e) { var passwordBox = (System.Windows.Controls.PasswordBox)sender; if (!String.Equals(GetBindedPassword(passwordBox), passwordBox.Password)) { SetBindedPassword(passwordBox, passwordBox.Password); //目的是让打字的光标显示在最后 int length = passwordBox.Password.Length; SetPasswordBoxSelection(passwordBox, length, length); } } public static string GetBindedPassword(DependencyObject obj) { return (string)obj.GetValue(BindedPasswordProperty); } public static void SetBindedPassword(DependencyObject obj, string value) { obj.SetValue(BindedPasswordProperty, value); } public static readonly DependencyProperty BindedPasswordProperty = DependencyProperty.RegisterAttached("BindedPassword", typeof(string), typeof(PasswordBoxBindingHelper),new UIPropertyMetadata(string.Empty, OnBindedPasswordChanged)); private static void OnBindedPasswordChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e) { var passwordBox = obj as System.Windows.Controls.PasswordBox; if (passwordBox != null) { passwordBox.Password = e.NewValue == null ? string.Empty : e.NewValue.ToString(); } } /// <summary> /// 在更改了密码框的密码后, 需要手动更新密码框插入符(CaretIndex)的位置, 可惜的是, /// 密码框并没有给我们提供这样的属性或方法(TextBox有, PasswordBox没有), /// 可以采用下面的方法来设置 /// </summary> /// <param name="passwordBox"></param> /// <param name="start"></param> /// <param name="length"></param> private static void SetPasswordBoxSelection(System.Windows.Controls.PasswordBox passwordBox, int start, int length) { var select = passwordBox.GetType().GetMethod("Select", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic); select.Invoke(passwordBox, new object[] { start, length }); } } }
MainWindow的ViewModel文件MainViewModel.cs 提供绑定数据和命令及命令实现方法
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Input; using System.Windows; namespace EventCommandDemo { public class MainViewModel : ViewModelBase { public MainViewModel() { cboMouseEnterCommand = new ViewModelCommand((Object parameter) => { cboMouseEnterEvent(); }); cboTextBoxChangedCommand = new ViewModelCommand((Object parameter) => { cboTextBoxChangedEvent(); }); cboTextBoxBaseChangedCommand = new ViewModelCommand((Object parameter) => { cboTextBoxBaseChangedEvent(); }); cboSelectionChangedCommand = new ViewModelCommand((Object parameter) => { cboSelectionChangedEvent(); }); btnClickCommand = new ViewModelCommand((Object parameter) => { btnClickEvent(); }); btnMouseDoubleClickCommand = new ViewModelCommand((Object paramenter) => { btnMouseDoubleClickEvent(); }); pwdGotFocusCommand = new ViewModelCommand((Object paramenter) => { pwdGotFocusEvent(); }); chkCheckedCommand = new ViewModelCommand((Object paramenter) => { chkCheckedEvent(); }); chkUncheckedCommand = new ViewModelCommand((Object paramenter) => { chkUncheckedEvent(); }); var tempList =new string[]{"一个","两个","三个"}; ListCollection = tempList; } #region 事件命令 /// <summary> /// 下拉框 鼠标进入事件命令 /// </summary> public ICommand cboMouseEnterCommand { get; private set; } /// <summary> /// 下拉框文本改变事件命令,通过TextBox.TextChanged /// </summary> public ICommand cboTextBoxChangedCommand { get;private set; } /// <summary> /// 下拉框文本改变事件命令,通过TextBoxBase.TextChanged /// </summary> public ICommand cboTextBoxBaseChangedCommand { get; private set; } /// <summary> /// 下拉框，选中事件 /// </summary> public ICommand cboSelectionChangedCommand { get; private set; } /// <summary> /// 登陆按钮单机事件命令 /// </summary> public ICommand btnClickCommand { get; private set; } /// <summary> /// 登陆按钮双击事件命令 /// </summary> public ICommand btnMouseDoubleClickCommand { get; private set; } /// <summary> /// 密码框获取焦点事件命令 /// </summary> public ICommand pwdGotFocusCommand { get; private set; } /// <summary> /// 多选框非选中事件命令 /// </summary> public ICommand chkUncheckedCommand { get;private set; } /// <summary> /// 多选框选中事件命令 /// </summary> public ICommand chkCheckedCommand { get;private set; } #endregion #region 事件执行方法 /// <summary> /// 下拉框 鼠标进入事件,执行方法。 /// </summary> private void cboMouseEnterEvent() { MessageBox.Show("下拉框，鼠标进入事件被触发了"); } /// <summary> /// 下拉框文本改变事件,执行方法 /// </summary> private void cboTextBoxBaseChangedEvent() { MessageBox.Show("TextBoxBase - 用户名输入，下拉框文本改变事件被触发了"); } private void cboTextBoxChangedEvent() { MessageBox.Show("TextBox - 用户名输入，下拉框文本改变事件被触发了"); } /// <summary> /// 下拉框选中事件，执行方法 /// </summary> private void cboSelectionChangedEvent() { MessageBox.Show("下拉框，下拉框选中一个Item事件被触发了"); } /// <summary> /// 登陆按钮单机事件,执行方法 /// </summary> private void btnClickEvent() { MessageBox.Show("登陆按钮，鼠标单机（Click）事件被触发了"); } /// <summary> /// 登陆按钮双击事件，执行方法 /// </summary> private void btnMouseDoubleClickEvent() { MessageBox.Show("登陆按钮，鼠标双击事件被触发了"); } /// <summary> /// 密码框获取焦点事件，执行方法 /// </summary> private void pwdGotFocusEvent() { MessageBox.Show("密码框获取了焦点，事件被触发了"); } /// <summary> /// 多选框，非选中状态事件，执行方法 /// </summary> private void chkUncheckedEvent() { MessageBox.Show("多选框没选中，事件被触发了"); } /// <summary> /// 多选框，选中状态事件，执行方法 /// </summary> private void chkCheckedEvent() { MessageBox.Show("多选框选中，事件被触发了"); } #endregion #region 成员 private string[] listCollection; #endregion #region 属性 public string[] ListCollection { get { return listCollection; } set { this.SetProperty(ref this.listCollection,value);} } #endregion } }
ViewModel辅助类有ViewModelBase.cs，ViewModelCommand.cs 分别提供属性更改通知和Command命令接口ICommand实现类
using System; using System.Collections.Generic; using System.ComponentModel; using System.Linq; using System.Runtime.CompilerServices; using System.Text; namespace EventCommandDemo { public class ViewModelBase : INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; #region 支持.NET4.5 protected bool SetProperty<T>(ref T storage, T value, [CallerMemberName] string propertyName = null) { if (object.Equals(storage, value)) { return false; } storage = value; this.OnPropertyChanged(propertyName); return true; } private void OnPropertyChanged([CallerMemberName] string propertyName = null) { var eventHandler = this.PropertyChanged; if (eventHandler != null) { eventHandler(this, new PropertyChangedEventArgs(propertyName)); } } #endregion #region 支持.NET4.0 //private static string GetProperyName(string methodName) //{ // if (methodName.StartsWith("get_") || methodName.StartsWith("set_") || // methodName.StartsWith("put_")) // { // return methodName.Substring("get_".Length); // } // throw new Exception(methodName + " not a method of Property"); //} //protected bool SetProperty<T>(ref T storage, T value) //{ // if (object.Equals(storage, value)) { return false; } // storage = value; // string propertyName = GetProperyName(new System.Diagnostics.StackTrace(true).GetFrame(1).GetMethod().Name); // this.OnPropertyChanged(propertyName); // return true; //} //private void OnPropertyChanged(string propertyName) //{ // var eventHandler = this.PropertyChanged; // if (eventHandler != null) // { // eventHandler(this, new PropertyChangedEventArgs(propertyName)); // } //} #endregion } }
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace EventCommandDemo { public class ViewModelCommand : System.Windows.Input.ICommand { private Action<Object> action; public Action<Object> ViewModelAction { get { return action; } set { action = value; } } public ViewModelCommand(Action<Object> act) { action = act; } public bool CanExecute(Object parameter) { return true; } public void Execute(Object parameter) { this.ViewModelAction(parameter); } public event EventHandler CanExecuteChanged { add { } remove { } } } }
事件被绑定后触发相关事件界面：
这里分享源码EventCommandDemo.zip文件下载地址，希望大家在技术的殿堂里都能快速成长。
源码下载：
本文作者夜神，首发博客园，转载请注明。