在一个按钮WPF/MVVM中绑定两个命令

Question

我有一个选项卡控件包含两个选项卡,一个显示正在运行的进程的消息,另一个向我显示一个网页!

当我按下开始流程运行并显示消息时,我有三个按钮(启动,停止和清除).

我需要的是我按下开始按钮,两个标签,显示我所需的内容.这意味着我需要两个绑定两个命令到同一个按钮

你知道怎么绑定1个按钮两个命令吗？

我正在使用MVVM,而且我是MVVM的新手.

<Button Content="Start" Command="{Binding StartProcess_Command }" Height="25" Width="60" Grid.Row="0" Grid.Column="0" Margin="10"/>
<Button Content="Stop"  Command="{Binding StopProcess_Command}" Height="25" Width="60" Grid.Row="0" Grid.Column="1" Margin="10"/>
<Button Content="Clear" Command="{Binding ClearBtn_Command}" Height="25" Width="60" Grid.Row="0" Grid.Column="2" Margin="10"/>
<telerik:RadTabControl HorizontalAlignment="Stretch" VerticalAlignment="Stretch"  Grid.Row="1" Grid.ColumnSpan="4" Margin="10">
    <telerik:RadTabItem Header="Maestro" IsSelected="{Binding Path=MaestroSelected}">
        <ScrollViewer VerticalScrollBarVisibility="Visible" HorizontalScrollBarVisibility="Visible">
            <local:WPFBrowser/>
        </ScrollViewer>
    </telerik:RadTabItem>
    <telerik:RadTabItem Header="Messages">
        <Grid Background="LightGray">
            <ScrollViewer VerticalScrollBarVisibility="Visible" HorizontalScrollBarVisibility="Visible">
                <TextBlock TextWrapping="Wrap" Text="{Binding Path=output_process,UpdateSourceTrigger=Default}"/>
            </ScrollViewer>
        </Grid>
    </telerik:RadTabItem>
</telerik:RadTabControl >

这是WPFBrowser.cs代码:

         public WPFBrowser()
            {
                ServerString = "localhost"; //defualt value
                PortString = "9999"; //default value
                this.refreshCommand = new Lunch_Maestro.ViewModel.Command(DoRefreshCommand);
                m_WPFBrowser = new WebBrowser()
                {
                    HorizontalAlignment = System.Windows.HorizontalAlignment.Stretch,
                    VerticalAlignment = System.Windows.VerticalAlignment.Stretch
                };

                m_WPFBrowser.Navigated += WPFBrowser_Navigated;

                this.Content = m_WPFBrowser;
            }

            private void WPFBrowser_Navigated(object sender, System.Windows.Navigation.NavigationEventArgs e)
            {
                this.HideScriptErrors(m_WPFBrowser, true);
            }


            /// <summary>
            /// Found this link with interesting scenerios for script erros...
            /// http://social.msdn.microsoft.com/Forums/vstudio/en-US/4f686de1-8884-4a8d-8ec5-ae4eff8ce6db/new-wpf-webbrowser-how-do-i-suppress-script-errors?forum=wpf
            /// </summary>
            public void HideScriptErrors(WebBrowser wb, bool Hide)
            {
                FieldInfo fiComWebBrowser = typeof(WebBrowser).GetField("_axIWebBrowser2", BindingFlags.Instance | BindingFlags.NonPublic);
                if (fiComWebBrowser == null) return;

                object objComWebBrowser = fiComWebBrowser.GetValue(wb);

                if (objComWebBrowser == null) return;

                objComWebBrowser.GetType().InvokeMember("Silent", BindingFlags.SetProperty, null, objComWebBrowser, new object[] { Hide });

            }


            private void DoRefreshCommand()
            {
                m_WPFBrowser.Navigate(new Uri("http://" + ServerString + ":" + PortString + "/"));
            }

            private bool _maestroSelected;
            public bool MaestroSelected
            {
                get { return _maestroSelected; }
                set
                {
                    _maestroSelected = value;
                    if (_maestroSelected == true)
                        m_WPFBrowser.Navigate(new Uri("http://" + ServerString + ":" + PortString + "/"));
                    OnPropertyChanged("MaestroSelected");
                }
            }

            private readonly WebBrowser m_WPFBrowser;

            private string _serverString;
            public string ServerString
            {
                get { return _serverString; }
                set
                {
                    _serverString = value;
                    OnPropertyChanged("ServerString");
                }
            }

            private string _portString;
            public string PortString
            {
                get { return _portString; }
                set
                {
                    _portString = value;
                    OnPropertyChanged("PortString");
                }
            }

            private Lunch_Maestro.ViewModel.Command refreshCommand;
            public Lunch_Maestro.ViewModel.Command RefreshCommand
            {
                get { return refreshCommand; }
            }
// and Inotify property changes here

Answer 1

您可以像这样调用多个命令：

// xmlns:i="http://schemas.microsoft.com/xaml/behaviors"

<Button>
    <i:Interaction.Triggers>
        <i:EventTrigger EventName="Click">
            <i:InvokeCommandAction Command="{Binding Cmd1}" />
            <i:InvokeCommandAction Command="{Binding Cmd2}" />
            <i:InvokeCommandAction Command="{Binding Cmd3}" />
        </i:EventTrigger>
    </i:Interaction.Triggers>
</Button>

如果您需要的话，这还允许您控制命令执行顺序

PS：您只需要安装Microsoft.Xaml.Behaviors.WpfNuGet包即可。

Answer 2

你想点击一个Button并运行两段代码......它听起来真的不那么复杂.使用其中一个可用的RelayCommands,问题可以修复如下:

public ICommand SomeCommand
{
    get { return new ActionCommand(action) => { RunFirstFunction(action); 
        RunSecondFunction(action) }, canExecute => someCondition); }
}

在XAML中:

<Button Command="{Binding SomeCommand}" CommandParameter="{Binding SomeObject}">
    Click Me
</Button>

ActionCommand是我自己的形式RelayCommand,但所有的delegate ICommand实现都大致相同,可以这样工作.该CommandParameter值作为action变量进入代码并传递给两个函数.

Answer 3

您可以使用Prism框架中的CompositeCommand。在视图模型中创建一个附加的 CompositeCommand，使用此 CompositeCommand 注册两个普通命令并将按钮绑定到该 CompositeCommand。

有关如何使用 CompositeCommands 的信息，请参阅第 130 页的Prism 文档。

您的应用程序需要引用 Prism 包中包含的 Microsoft.Practices.Prism.dll。