Caliburn Micro学习一 Installation
Caliburn Micro学习二 Infrastructure
如果说WPF推崇的Binding开辟了一条UI开发新的方式——让写代码的人专注在代码上,让界面设计师去实现界面,他们工作在同一个项目上,使用不同的IDE,最终Build出来真正的产品,那Caliburn Micro无疑是一个加速器,它不仅加速了Binding的使用范畴,还加速了代码的编写速度。
首先,得介绍另外一个Assembly:
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
这个Assembly包含在Express Blend SDK里面,Microsoft Download Page:http://www.microsoft.com/en-us/download/details.aspx?id=3062
没有Caliburn.Micro,绑定到一个Event到一个ICommand
public ICommand CommandDataPathSelectionChanged { get { if (_cmd_path_selchged == null) _cmd_path_selchged = new ACRelayCommand( x => OnDataPathSelectionChanged(x) ); return _cmd_path_selchged; } }
其中,ACRelayCommand的定义:
public class ACRelayCommand : ICommand { #region Fields readonly Action<object> _execute; readonly Predicate<object> _canExecute; #endregion // Fields #region Constructors /// <summary> /// Creates a new command that can always execute. /// </summary> /// <param name="execute">The execution logic.</param> public ACRelayCommand(Action<object> execute) : this(execute, null) { } /// <summary> /// Creates a new command. /// </summary> /// <param name="execute">The execution logic.</param> /// <param name="canExecute">The execution status logic.</param> public ACRelayCommand(Action<object> execute, Predicate<object> canExecute) { if (execute == null) throw new ArgumentNullException("execute"); _execute = execute; _canExecute = canExecute; } #endregion // Constructors #region ICommand Members [DebuggerStepThrough] public bool CanExecute(object parameter) { return _canExecute == null ? true : _canExecute(parameter); } public event EventHandler CanExecuteChanged { add { CommandManager.RequerySuggested += value; } remove { CommandManager.RequerySuggested -= value; } } public void Execute(object parameter) { _execute(parameter); } #endregion // ICommand Members }
而作为对比,使用了Caliburn.Micro,可以直接绑定Event到一个Method
<ComboBox Name="cmbDataPath" Width="485" ItemsSource="{Binding DataPathList}" SelectedItem="{Binding SelectedDataPath}" > <i:Interaction.Triggers> <i:EventTrigger EventName="SelectionChanged"> <cal:ActionMessage MethodName="OnSelectionChanged"> <cal:Parameter Value="$source" /> <cal:Parameter Value="$eventArgs" /> </cal:ActionMessage> </i:EventTrigger> </i:Interaction.Triggers> </ComboBox>
其中,Parameter的Value可以指定如下值:
- $eventArgs – EventArgs对象.
- $dataContext – UI界面空间的DataContext.
- $source – 实际FrameworkElement.
- $view - 绑定在ViewModel的View.
- $executionContext - 执行上下文.
- $this - UIelement 对象.
另外,常用的XAML中绑定语法:
<Button Content="DoSomething"
cal:Message.Attach="[Event Click] = [Action DoSomething($dataContext)]" />
甚至同时绑定多个Event:
<Button Content="Let's Talk" cal:Message.Attach="[Event MouseEnter] = [Action Talk('Hello', Name.Text)]; [Event MouseLeave] = [Action Talk('Goodbye', Name.Text)]" />
简化的语法:
<Button Content="Click Me" cal:Message.Attach="SayHello(Name)" />