Interaction Trigger Command WPF MVVM not triggering

Question

I am trying to bind command like below for a checkbox present in RadGridView's Column Header.

<telerik:GridViewCheckBoxColumn DataMemberBinding="{Binding IsSelected, Mode=TwoWay}" Width="85" AutoSelectOnEdit="True" EditTriggers="CellClick">                                                
  <telerik:GridViewCheckBoxColumn.Header>
     <CheckBox Command="{Binding ShowAllInDTCClickedCommand}" Content="Sh">
         <i:Interaction.Triggers>
              <i:EventTrigger EventName="Checked">                                                                
                  <i:InvokeCommandAction Command="{Binding ShowAllInDTCCheckedCommand}"/>
              </i:EventTrigger>
              <i:EventTrigger EventName="Unchecked">                                                                
                  <i:InvokeCommandAction Command="{Binding ShowAllInDTCUncheckedCommand}"/>
              </i:EventTrigger>
         </i:Interaction.Triggers>
      </CheckBox>
   </telerik:GridViewCheckBoxColumn.Header>
</telerik:GridViewCheckBoxColumn>

And trying to implement them in ViewModel like below.

    public DelegateCommand ShowAllInDTClickedCommand { get; set; }
    public DelegateCommand ShowAllInDTCCheckedCommand { get; set; }
    public DelegateCommand ShowAllInDTCUncheckedCommand { get; set; }


    ShowAllInDTClickedCommand = new DelegateCommand(ShowAllInDTClicked);
    ShowAllInDTCCheckedCommand = new DelegateCommand(ShowAllInDTCChecked);
    ShowAllInDTCUncheckedCommand = new DelegateCommand(ShowAllInDTCUnchecked);

    private void ShowAllInDTClicked()
    {
        //Do Something
    }

    private void ShowAllInDTCChecked()
    {
        //Do Something
    }

    private void ShowAllInDTCUnchecked()
    {
        //Do Something
    }

But these commands are not executing i.e. code is not reachable at all. What I am missing?

Basically, I am trying to check property of that column for all records present in the grid. something like 'Select All', 'DeSelect All'... — Upendhar Singirikonda, Nov 01 '18 at 15:26
Yes, I can populate objects, and everything else is working fine. Except these commands... — Upendhar Singirikonda, Nov 01 '18 at 15:38
Judging from your comments to mm8 it sounds like there's a issue with your interactivity triggers. Maybe try this instead https://stackoverflow.com/questions/5566050/executing-a-command-on-checkbox-checked-or-unchecked It seems like all you want is to find out the status of the checkbox and execute code accordingly so just passing that CommandParameter can give you that info. — user2619824, Nov 01 '18 at 21:00
Where do you make the assignment ShowAllInDTClickedCommand = new DelegateCommand(ShowAllInDTClicked); In the constructor or somewhere else? — Quergo, Nov 01 '18 at 21:20
@user2619824 If you observe my question, I am already having that... — Upendhar Singirikonda, Nov 02 '18 at 10:29
Look more closely. You have a command but no CommandParameter. Try it using the Parameter. — user2619824, Nov 02 '18 at 22:36

score 1 · Answer 1 · answered Nov 01 '18 at 15:45

1

If the DelegateCommand properties are defined in your view model, you should bind to them like this:

<i:EventTrigger EventName="Checked">
    <i:InvokeCommandAction Command="{Binding DataContext.ShowAllInDTCCheckedCommand, 
                                RelativeSource={RelativeSource AncestorType=telerik:RadGridView}}"/>
</i:EventTrigger>

answered Nov 01 '18 at 15:45

mm8

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Thank you for your answer. I modified the code same as you mentioned. But, it is not working. – Upendhar Singirikonda Nov 01 '18 at 15:54
So where are your commands defined and what's the DataContext of your RadGridView? – mm8 Nov 01 '18 at 15:59
My commands defined in ViewModel. And I can trigger other commands bound in this XAML with the the same ViewModel – Upendhar Singirikonda Nov 01 '18 at 16:01
You didn't answer my question...What's the DataContext of the GridView? And what's the ItemsSource of the GridView? And what type is the commands in? – mm8 Nov 01 '18 at 16:07
Datacontext is ViewModel. Other commands which are working are Button commands. – Upendhar Singirikonda Nov 01 '18 at 16:10
What button commands? Please edit your question and include all relevant parts. – mm8 Nov 01 '18 at 16:12
Let's say I add a button to this XAML and bind command of that button to this Command (for e.g. ShowAllInDTCCheckedCommand), then it is working fine. – Upendhar Singirikonda Nov 01 '18 at 16:47
It depends on *where* you add the Button and what its DataContext is. – mm8 Nov 02 '18 at 12:46
My XAML has Button and GridView. GridView has Columns. And one column has this checkbox. My XAML has ViewModel as Datacontext. If I have an observable collection in ViewModel, I can bind that to grid in my View. Could you please tell me now what will be the Datacontext to checkbox in ColHeader? – Upendhar Singirikonda Nov 02 '18 at 13:34
Not the view model. That's why you should use a RelativeSource when you bind to the command as I stated in my answer. – mm8 Nov 02 '18 at 13:35
But it is not working as expected when I specify gridview as relativesource – Upendhar Singirikonda Nov 02 '18 at 13:37
Did you add "DataContext." to the binding path? What if you set AncestorType to Window or UserControl or whatever type your view is? – mm8 Nov 02 '18 at 13:40
Yes, I added, still not working. and Yes, I also tried by adding 'UserControl' as ancestor type still no use. – Upendhar Singirikonda Nov 02 '18 at 13:52

Interaction Trigger Command WPF MVVM not triggering

1 Answers1