WPF Context Menu command Binding

Question

I have tried few solutions given in SO, but still i'm unable to trigger the command.

XAML:

 <Image Source="{Binding CurrentImage.Source, Mode=OneWay}" Grid.Row="0" Grid.Column="1" Tag="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType= Window}}">
     <Image.ContextMenu>
            <ContextMenu DataContext="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
                  <MenuItem Header="Edit Image" Command="{Binding PlacementTarget.Tag.EditImageCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"></MenuItem>
            </ContextMenu>
     </Image.ContextMenu>

ViewModel:

private ICommand _EditImageCommand;
public ICommand EditImageCommand
   {
      get
        {
           return _EditImageCommand ?? (_EditImageCommand = new CommandHandler(() => EditImage(), _canExecute));
        }
   }

 public void EditImage()
 {

 }

That binding via Tag and setting DataContext fills wrong (especially for MVVM). Check binding errors in Output window. It should be enough to set path only in Command binding normally. — Sinatr
– Sinatr, Commented Jul 27, 2016 at 12:02

Mafii · Accepted Answer · 2016-07-27 11:56:22Z

2

Change:

private ICommand _EditImageCommand;
private ICommand EditImageCommand
   {
      get
        {
           return _EditImageCommand ?? (_EditImageCommand = new CommandHandler(() => EditImage(), _canExecute));
        }
   }

 public void EditImage()
 {

 }

to

private ICommand _EditImageCommand;
public ICommand EditImageCommand // has to be public
   {
      get
        {
           return _EditImageCommand ?? (_EditImageCommand = new CommandHandler(() => EditImage(), _canExecute));
        }
   }

 public void EditImage()
 {

 }

Commands have to be public to be accessed (or internal for the sake of correctness).

Also, change your xaml to:

<Image Source="{Binding CurrentImage.Source, Mode=OneWay}" Grid.Row="0" Grid.Column="1" Tag="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType= Window}}">
     <Image.ContextMenu>
            <ContextMenu DataContext="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
                  <MenuItem Header="Edit Image" Command="{Binding EditImageCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=ContextMenu}}"></MenuItem>
            </ContextMenu>
     </Image.ContextMenu>

edited Jul 27, 2016 at 11:56

answered Jul 27, 2016 at 11:52

Mafii

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2 Comments

A Coder Over a year ago

Have changed, but still it doesn't.

Mafii Over a year ago

Check my edit. Is your DataContext of the window you are in the viewmodel you posted? Why do you use the Relative source self?

A Coder · Accepted Answer · 2016-07-27 12:02:15Z

1

Have changed my XAML to,

<Window.Resources>
        <local:ImageList x:Key="SliderViewModel"></local:ImageList>
</Window.Resources>

    <Image Source="{Binding CurrentImage.Source, Mode=OneWay}" Grid.Row="0" Grid.Column="1">
        <Image.ContextMenu>
               <ContextMenu>
                     <MenuItem Header="Edit Image" Command="{Binding EditImageCommand, Source={StaticResource SliderViewModel}}"></MenuItem>
                 </ContextMenu>
         </Image.ContextMenu>
     </Image>

Working fine. Thanks

answered Jul 27, 2016 at 12:02

A Coder

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1 Comment

A Coder Over a year ago

Yes ofcourse it worked only after changing the command to public along with the XAML changes. Thanks you helped at right point.

Andriy Shevchenko · Accepted Answer · 2016-11-28 23:24:17Z

1

Another nice workaround is to declare a static instance of your view model in App.xaml: <ViewModelTypeName x:Key="ViewModelName" d:IsDataSource="True" />and bind like this Command="{Binding Source={StaticResource ViewModelName}, Path=MyCommand}" I had the same issue when i needed to bind from Window and menuitem's native DataContext simultaneously. Also this solution looks not that complicated.

answered Nov 28, 2016 at 23:24

Andriy Shevchenko

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