Silverlight call command from button within listbox item template

Question

I have seen this question asked a few times but I have not seen been able to find a complete answer to my scenario.

Within my project I have a user control that I have created as a listbox item. Within this user control I have a button

            <Button x:Name="DetailButton"
                Grid.Column="1"
                Width="107"
                Height="23"
                Margin="196,94,0,0"
                HorizontalAlignment="Left"
                VerticalAlignment="Top"
                Click="MoreDetail_Click"
                Command="{Binding GetCFSDetailCommand}"
                Content="View Details [+]" />

the button has a click event specific to the view this basically expands or collapses a grid row based upon the state of visibility. I used an event here since it was specific to the ui. This button also has a command which is called in the VM.

VM code

public class SearchViewModel : INotifyPropertyChanged
{
    private DelegateCommand _getCFSDetailCommand;
public DelegateCommand GetCFSDetailCommand
    {
        get
        {
            if (this._getCFSDetailCommand == null)
                this._getCFSDetailCommand = new DelegateCommand(GetCFSDetailCommandExecute, CanGetCFSDetailCommandExecute);

            return this._getCFSDetailCommand;      
        }

    }
private void GetCFSDetailCommandExecute(object parameter)
    {
        //bind collection to model call here
    }

The issue I am having is the command on the button is "lost" or never called when inside the listbox item I have the view bound to the vm and if I place this command on any other button within the view the command is called. Can anyone help me understand how to call a Command bound to button within a listbox item?

Thank you in advance

score 2 · Accepted Answer · edited May 23 '17 at 12:20

2

randyc, In your original (first) post you was binding the CommandParameter to a local data context of list item. In the second post you miss that binding, and I think it is impossible in the context of second port. In your case I propose to use the Element to Element binding to bind to the GetCFSDetailCommand command from the parent data context.

edited May 23 '17 at 12:20

Community

1
1

answered Jun 15 '11 at 07:25

Safor

130
7

Thanks Safor. And you are correct the element to element binding helped to resolve the issue of the user control (and button inside) losing it's data context from the parent page. I also apologize on the syntax in the original post, the command parameter was not being used. I had it in there originally as I was intending to pass a parameter to the command but I ended up using another approach. I have updated the original question to remove the confusion – rlcrews Jun 16 '11 at 16:59

rlcrews · Answer 2 · 2011-06-16T17:05:04.620

The issue in calling a command within the usercontrol as a listbox item is that the pattern is looking for the command within the context of the control. Apparently the listbox item jumps outside of the visual tree and so binding is not inherited.
To correct this I needed to explicitly set the data context of the button to the ViewModel. This was ultimately solved using the Element to Element binding which allowed me to point the datacontext of the user control to the main view that contained it.

Hope this helps

Silverlight call command from button within listbox item template

2 Answers2