Button is not disabled when command is_问答_开发者

I like the MVVM Light framework, as many said, simple but powerful.

I am trying to disable a button, does same thing as in EventToCommand sample (working allright, but targeted or 3.5). I added an IsEnabled event, is firing.

My program is targeted for 4.0.

my command is disabled allright, but the button stays enabled.

I have added an event in my program too, is not firing.

don't know what I am missing.

my Xaml:

<Window x:Class="MyWPFApp.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
    xmlns:cmd="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.WPF4"
    xmlns:vw="clr-namespace:MyWPFApp.Views"

    Title="MainWindow"
    Height="300"
    Width="300"
    SizeToContent="WidthAndHeight"
    DataContext="{Binding Source={StaticResource Locator}, Path=v_MainWindow}">

<Window.Resources>
    <!--<ResourceDictionary x:Key="ResDict">
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="/Skins/MainSkin.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>-->
    <ControlTemplate x:Key="ButtonTemplate"
                     TargetType="Button">
        <Grid x:Name="Root"
              Opacity="0.8"
              RenderTransformOrigin="0.5,0.5">
            <Grid.RenderTransform>
                <TransformGroup>
                    <ScaleTransform />
                    <SkewTransform />
                    <RotateTransform />
                    <TranslateTransform />
                </TransformGroup>
            </Grid.RenderTransform>

            <VisualStateManager.VisualStateGroups>
                <VisualStateGroup x:Name="CommonStates">
                    <VisualStateGroup.Transitions>
                        <VisualTransition From="MouseOver"
                                          GeneratedDuration="00:00:00.2000000"
                                          To="Normal" />
                        <VisualTransition From="Normal"
                                          GeneratedDuration="00:00:00.2000000"
                                          To="MouseOver" />
                    </VisualStateGroup.Transitions>
                    <VisualState x:Name="Normal" />
                    <VisualState x:Name="MouseOver">
                        <Storyboard>
                            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                           Duration="00:00:00.0010000"
                                                           Storyboard.TargetName="Root"
                                                           Storyboard.TargetProperty="(UIElement.Opacity)">
                                <SplineDoubleKeyFrame KeyTime="00:00:00"
                                                      Value="1" />
                            </DoubleAnimationUsingKeyFrames>
                        </Storyboard>
                    </VisualState>
                    <VisualState x:Name="Pressed">
                        <Storyboard>
                            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                           Duration="00:00:00.0010000"
                                                           Storyboard.TargetName="Root"
                                                           Storyboard.TargetProperty="(UIElement.Opacity)">
                                <SplineDoubleKeyFrame KeyTime="00:00:00"
                                                      Value="1" />
                            </DoubleAnimationUsingKeyFrames>
                            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                           Duration="00:00:00.0010000"
                                                           Storyboard.TargetName="Root"
                                                           Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleX)">
                                <SplineDoubleKeyFrame KeyTime="00:00:00"
                                                      Value="0.9" />
                       开发者_如何转开发     </DoubleAnimationUsingKeyFrames>
                            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                           Duration="00:00:00.0010000"
                                                           Storyboard.TargetName="Root"
                                                           Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[0].(ScaleTransform.ScaleY)">
                                <SplineDoubleKeyFrame KeyTime="00:00:00"
                                                      Value="0.9" />
                            </DoubleAnimationUsingKeyFrames>
                        </Storyboard>
                    </VisualState>
                    <VisualState x:Name="Disabled">
                        <Storyboard>
                            <DoubleAnimationUsingKeyFrames BeginTime="00:00:00"
                                                           Duration="00:00:00.0010000"
                                                           Storyboard.TargetName="Root"
                                                           Storyboard.TargetProperty="(UIElement.Opacity)">
                                <SplineDoubleKeyFrame KeyTime="00:00:00"
                                                      Value="0.4" />
                            </DoubleAnimationUsingKeyFrames>
                        </Storyboard>
                    </VisualState>
                </VisualStateGroup>
            </VisualStateManager.VisualStateGroups>
            <Rectangle Fill="{TemplateBinding Background}"
                       Stroke="Black"
                       RadiusX="8"
                       RadiusY="8" />
            <TextBlock HorizontalAlignment="Center"
                       VerticalAlignment="Center"
                       Text="{TemplateBinding Content}"
                       TextWrapping="Wrap"
                       FontSize="12"
                       FontWeight="Bold" />
        </Grid>
    </ControlTemplate>

    <Style x:Key="ButtonStyle"
           TargetType="Button">
        <Setter Property="Template"
                Value="{StaticResource ButtonTemplate}" />
        <Setter Property="Cursor"
                Value="Hand" />
    </Style>

</Window.Resources>

<Grid x:Name="LayoutRoot">
    <Grid.RowDefinitions>
        <RowDefinition />
        <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto" />
        <ColumnDefinition />
    </Grid.ColumnDefinitions>
    <StackPanel Grid.Row="0"  Grid.Column="0" Orientation="Vertical" HorizontalAlignment="Left">
        <Button Content="Change to Error Status" Style="{StaticResource ButtonStyle}" IsEnabledChanged="EnableChanged">
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="Click">
                    <cmd:EventToCommand Command="{Binding StatusCommand}"
                                   CommandParameter="{Binding RelativeSource={RelativeSource AncestorType=Button}, Path=Content}" MustToggleIsEnabled="True"/>
                </i:EventTrigger>
            </i:Interaction.Triggers>
        </Button>
        <Button Content="Change to Warning" Style="{StaticResource ButtonStyle}" IsEnabledChanged="EnableChanged">              
            <i:Interaction.Triggers>
                <i:EventTrigger EventName="Click">
                    <cmd:EventToCommand Command="{Binding StatusCommand}"
                                       CommandParameter="{Binding RelativeSource={RelativeSource AncestorType=Button}, Path=Content}" MustToggleIsEnabled="True"/>
                </i:EventTrigger>
            </i:Interaction.Triggers>
        </Button>
        <Button Content="Success" IsEnabled="False"/>
        <Button Content="Info"/>
    </StackPanel>
    <TextBlock Grid.Row="0"  Grid.Column="1"
               FontSize="36"
               FontWeight="Bold"
               Foreground="Purple"
               Text="{Binding Welcome}"
               VerticalAlignment="Center"
               HorizontalAlignment="Center"
               TextWrapping="Wrap">
       <!--<i:Interaction.Triggers>
           <i:EventTrigger EventName="MouseEnter">
               <cmd:EventToCommand Command="{Binding StatusCommand}"
                                   CommandParameter="Error" />
           </i:EventTrigger>
       </i:Interaction.Triggers>-->
    </TextBlock>
    <vw:v_StatusBar Grid.Row="1" Grid.ColumnSpan="2" />

</Grid>

MY code in viewmodel

using System.Windows;
using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.Command;
using GalaSoft.MvvmLight.Messaging;



namespace MyWPFApp.ViewModel
{
/// <summary>
/// This class contains properties that the main View can data bind to.
/// <para>
/// Use the <strong>mvvminpc</strong> snippet to add bindable properties to this ViewModel.
/// </para>
/// <para>
/// You can also use Blend to data bind with the tool's support.
/// </para>
/// <para>
/// See http://www.galasoft.ch/mvvm/getstarted
/// </para>
/// </summary>
public class vm_MainWindow : ViewModelBase
{
    public string Welcome
    {
        get
        {
            return "Welcome to Geert's WPF template (based on MVVM Light)";
        }
    }

    private string _status = "Initialized...";

    public string Status
    {
        get
        {
            return _status;
        }

        private set
        {
            if (_status == value)
            {
                MessageBox.Show("Status is already " + value);
                return;
            }

            _status = value;

            MessageBox.Show("Setting status to " + _status);
            Messenger.Default.Send<string>(value, "StatusChange");

        }
    }

    public RelayCommand<string> StatusCommand
    {
        get;
        private set;
    }


    /// <summary>
    /// Initializes a new instance of the MainViewModel class.
    /// </summary>
    public vm_MainWindow()
    {
        if (IsInDesignMode)
        {
            // Code runs in Blend --> create design time data.
        }
        else
        {
            // Code runs "for real"

            StatusCommand = new RelayCommand<string>(p => Status = string.Format("{0}", p), p => p != _status);

        }
    }

    ////public override void Cleanup()
    ////{
    ////    // Clean up if needed

    ////    base.Cleanup();
    ////}
}

}

Found the problem, CanExecuteChanged simple never fired!!!!!!

first, I added (in relaycommand) what is suggested in the remarks here: http://msdn.microsoft.com/query/dev10.query?appId=Dev10IDEF1&l=EN-US&k=k(SYSTEM.WINDOWS.INPUT.COMMANDMANAGER.REQUERYSUGGESTED);k(TargetFrameworkMoniker-%22.NETFRAMEWORK%2cVERSION%3dV4.0%22);k(DevLang-CSHARP)&rd=true

Then I noticed that only the last button was enabled/disabled.

again logical, every handler added in relaycommand overwrote the previous one.

so, I added event handling support in eventtocommand.

and, everything is wokring fine.

will send my corrections to Mr Buignon hoping that he will check and release officially.

ps only checked and changed for WPF 4.0 (only thing i need now)