大家好
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。
原理
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;
创建ChildWindow窗体
<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="" Height=""
Title="{Binding Title}"
x:Name="confirmationWindow" Topmost="True" WindowStyle="ToolWindow" WindowStartupLocation="CenterScreen">
<Grid x:Name="LayoutRoot" Margin="">
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions> <ContentControl HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Grid.Row="" Content="{Binding Content}"/> <Button Content="Cancel" Width="" Height="" HorizontalAlignment="Right" Margin="0,12,0,0" Grid.Row="">
<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="" Height="" HorizontalAlignment="Right" Margin="0,12,79,0" Grid.Row="">
<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>
创建ChildWindow的基类
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();
}
}
到此子窗体已经完成
如何调用
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="" Width="">
<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="" Height=""/>
<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"; });
}
}
总结
这样的写法比较符合MVVM的分层思想,子窗体可以随心定制,而不需要去改逻辑层的代码。具体代码以上全部提供,谢谢。