MVVM 将 EventArgs 作为命令参数传递 [英] MVVM Passing EventArgs As Command Parameter

问题描述

我正在使用 Microsoft Expression Blend 4
我有一个浏览器 ..,

I'm using Microsoft Expression Blend 4
I have a Browser ..,

[ XAML ] ConnectionView背后的空代码"

[ XAML ] ConnectionView " Empty Code Behind "

        <WebBrowser local:AttachedProperties.BrowserSource="{Binding Source}">
            <i:Interaction.Triggers>
                <i:EventTrigger>
                    <i:InvokeCommandAction Command="{Binding LoadedEvent}"/>
                </i:EventTrigger>
                <i:EventTrigger EventName="Navigated">
                    <i:InvokeCommandAction Command="{Binding NavigatedEvent}" CommandParameter="??????"/>
                </i:EventTrigger>
            </i:Interaction.Triggers>
        </WebBrowser>  

[ C# ] AttachedProperties 类

public static class AttachedProperties
    {
        public static readonly DependencyProperty BrowserSourceProperty = DependencyProperty . RegisterAttached ( "BrowserSource" , typeof ( string ) , typeof ( AttachedProperties ) , new UIPropertyMetadata ( null , BrowserSourcePropertyChanged ) );

        public static string GetBrowserSource ( DependencyObject _DependencyObject )
        {
            return ( string ) _DependencyObject . GetValue ( BrowserSourceProperty );
        }

        public static void SetBrowserSource ( DependencyObject _DependencyObject , string Value )
        {
            _DependencyObject . SetValue ( BrowserSourceProperty , Value );
        }

        public static void BrowserSourcePropertyChanged ( DependencyObject _DependencyObject , DependencyPropertyChangedEventArgs _DependencyPropertyChangedEventArgs )
        {
            WebBrowser _WebBrowser = _DependencyObject as WebBrowser;
            if ( _WebBrowser != null )
            {
                string URL = _DependencyPropertyChangedEventArgs . NewValue as string;
                _WebBrowser . Source = URL != null ? new Uri ( URL ) : null;
            }
        }
    }

[ C# ] ConnectionViewModel 类

public class ConnectionViewModel : ViewModelBase
    {
            public string Source
            {
                get { return Get<string> ( "Source" ); }
                set { Set ( "Source" , value ); }
            }

            public void Execute_ExitCommand ( )
            {
                Application . Current . Shutdown ( );
            }

            public void Execute_LoadedEvent ( )
            {
                MessageBox . Show ( "___Execute_LoadedEvent___" );
                Source = ...... ;
            }

            public void Execute_NavigatedEvent ( )
            {
                MessageBox . Show ( "___Execute_NavigatedEvent___" );
            }
    }

[ C# ] ViewModelBase 类 这里

最后:
绑定命令效果很好，并且显示了 MessageBoxes

Finally :
Binding with commands works well and MessageBoxes shown

我的问题:
发生导航事件时如何将 NavigationEventArgs 作为命令参数传递?

推荐答案

它不容易被支持.这是 一篇文章，其中包含有关如何将 EventArgs 作为命令参数传递的说明.

It's not easily supported. Here's an article with instructions on how to pass EventArgs as command parameters.

您可能想考虑使用 MVVMLight - 它直接在命令中支持 EventArgs；您的情况将如下所示:

You might want to look into using MVVMLight - it supports EventArgs in command directly; your situation would look something like this:

 <i:Interaction.Triggers>
    <i:EventTrigger EventName="Navigated">
        <cmd:EventToCommand Command="{Binding NavigatedEvent}"
            PassEventArgsToCommand="True" />
    </i:EventTrigger>
 </i:Interaction.Triggers>

这篇关于MVVM 将 EventArgs 作为命令参数传递的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！