#以前写过的一篇博文,里面介绍的方法,在实际项目里频繁使用,分享至此
说起子窗体,大家都会想到ChildWindow,多熟悉的一个控件。不错,Sliverlight中已经提供了子窗体的具体实现,而在WPF中却没有这么好的事情(有的第三方控件商已经提供此控件)。最常见的实现方法就是在ViewModel中,直接New ChildWindow,然后直接Show。这样的方法也达到的要求。但是它不符合MVVM分层思想,再就是代码不美观,难以维护,今天我就给大家介绍一种美观又实用的方法。
通过Prism中提供的InteractionRequestTrigger事件触发器,实现点击按钮或者用户的某种操作弹出对话框的效果。另外,不要忘了引用此命名空间:
using Microsoft.Practices.Prism.Interactivity.InteractionRequest;
<Window x:Class="ChildWindowDemo.ChildWindow.ChildWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity" xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions" Width="300" Height="150" Title="{Binding Title}" x:Name="confirmationWindow" Topmost="True" WindowStyle="ToolWindow" WindowStartupLocation="CenterScreen"> <Grid x:Name="LayoutRoot" Margin="2"> <Grid.RowDefinitions> <RowDefinition /> <RowDefinition Height="Auto" /> </Grid.RowDefinitions> <ContentControl HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Grid.Row="0" Content="{Binding Content}"/> <Button Content="Cancel" Width="75" Height="23" HorizontalAlignment="Right" Margin="0,12,0,0" Grid.Row="1"> <i:Interaction.Triggers> <i:EventTrigger EventName="Click"> <ei:CallMethodAction TargetObject="{Binding ElementName=confirmationWindow}" MethodName="Close"/> </i:EventTrigger> </i:Interaction.Triggers> </Button> <Button Content="OK" Width="75" Height="23" HorizontalAlignment="Right" Margin="0,12,79,0" Grid.Row="1"> <i:Interaction.Triggers> <i:EventTrigger EventName="Click"> <ei:ChangePropertyAction PropertyName="Confirmed" TargetObject="{Binding}" Value="True"/> <ei:CallMethodAction TargetObject="{Binding ElementName=confirmationWindow}" MethodName="Close"/> </i:EventTrigger> </i:Interaction.Triggers> </Button> </Grid> </Window>
新建类:ChildWindowActionBase 并从TriggerAction<T>派生,代码如下:
public class ChildWindowActionBase : TriggerAction<FrameworkElement> { protected override void Invoke(object parameter) { var arg = parameter as InteractionRequestedEventArgs; if (arg == null) return; var windows = this.GetChildWindow(arg.Context); var callback = arg.Callback; EventHandler handler = null; handler = (o, e) => { windows.Closed -= handler; callback(); }; windows.Closed += handler; windows.ShowDialog(); } Window GetChildWindow(Notification notification) { var childWindow = this.CreateDefaultWindow(notification); childWindow.DataContext = notification; return childWindow; } Window CreateDefaultWindow(Notification notification) { return (Window)new ChildWindow.ChildWindow(); } }
主程序界面代码如下:
<Window x:Class="ChildWindowDemo.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:prism="http://www.codeplex.com/prism" xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity" xmlns:local="clr-namespace:ChildWindowDemo" Title="MainWindow" Height="200" Width="300"> <i:Interaction.Triggers> <prism:InteractionRequestTrigger SourceObject="{Binding ConfirmationRequest, Mode=OneWay}"> <local:ChildWindowActionBase/> </prism:InteractionRequestTrigger> </i:Interaction.Triggers> <Grid> <Button Command="{Binding RaiseConfirmation}" Content="Click Me !" HorizontalAlignment="Left" Margin="29,31,0,0" VerticalAlignment="Top" Width="217" Height="55"/> <TextBlock HorizontalAlignment="Left" Margin="29,106,0,0" TextWrapping="Wrap" Text="{Binding ConfirmationResult}" VerticalAlignment="Top"/> </Grid> </Window>对之对应的ViewModel:
public class MainWindowViewModel : NotificationObject { public MainWindowViewModel() { this.RaiseConfirmation = new DelegateCommand(this.OnRaiseConfirmation); this.ConfirmationRequest = new InteractionRequest<Confirmation>(); } public InteractionRequest<Confirmation> ConfirmationRequest { get; private set; } public DelegateCommand RaiseConfirmation { get; private set; } private string result; public string ConfirmationResult { get { return result; } set { result = value; this.RaisePropertyChanged(() => this.ConfirmationResult); } } private void OnRaiseConfirmation() { this.ConfirmationRequest.Raise( new Confirmation { Content = "是否确认", Title = "子窗体" }, (cb) => { ConfirmationResult = cb.Confirmed ? "确认" : "取消"; }); } }