Access my Window's DataContext inside a DataTemplate

Question

I'm working on a WPF application and I'm using the MVVM pattern. I use MVVMLight to help me handle some Events. I need to forward the "Click" event so that I can pass the arguments as well so that I can know for sure which item that sent the event. If I use the "Command" I cant know for sure that it was the selected item that sent the event - as the item doesnt need to be selected to right click on it.

This is my code for displaying a list of "order lines". There are two types of order lines, and for one of the data types; "AccessoryOrderLine" - I want to add a context menu.

My problem is that I cannot access my Window's DataContext. I've named the root node in the Window "root", and I'm trying to access the root's DataContext, but this failes with the following error:

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'ElementName=root'. BindingExpression:Path=DataContext.PackAccessory; DataItem=null; target element is 'EventToCommand' (HashCode=5903270); target property is 'Command' (type 'ICommand')

<ListBox HorizontalContentAlignment="Stretch" Margin="10,0,10,10" DockPanel.Dock="Bottom" Grid.Row="1" ItemsSource="{Binding OrderLines, NotifyOnSourceUpdated=True, NotifyOnTargetUpdated=True, UpdateSourceTrigger=PropertyChanged}">
    <ListBox.Resources>
        <DataTemplate DataType="{x:Type m:UnitOrderLine}">
             <v:OrderLine />
        </DataTemplate>
        <DataTemplate DataType="{x:Type m:AccessoryOrderLine}">
            <v:OrderLine>
                <v:OrderLine.ContextMenu>
                    <ContextMenu>
                        <MenuItem Header="Pack 1" IsCheckable="False">
                            <i:Interaction.Triggers>
                                <i:EventTrigger EventName="Click">
                                    <cmd:EventToCommand Command="{Binding ElementName=root, Path=DataContext.PackAccessory }" PassEventArgsToCommand="True" />
                                </i:EventTrigger>
                            </i:Interaction.Triggers>
                         </MenuItem>
                     </ContextMenu>
                 </v:OrderLine.ContextMenu>
             </v:OrderLine>
         </DataTemplate>
     </ListBox.Resources>
 </ListBox>

I've also tried to use "TemplatedParent" and then I get access to my "OrderLine" DataContext, but I cant get one step further back to my "MainWindowModel".

http://www.thomaslevesque.com/2011/03/21/wpf-how-to-bind-to-data-when-the-datacontext-is-not-inherited/

Found a solution to my problem :)

score 1 · Accepted Answer · answered Jun 28 '12 at 09:06

1

Found a solution. Updated my original post with the link to my solution.

answered Jun 28 '12 at 09:06

AndersLindas

137
1
9

score 0 · Answer 2 · answered Jun 28 '12 at 08:20

Its not issue with the DataTemplate. Binding with ElemetName works in all cases except in the case of ContextMenu since it does not lies in the same visual tree as of your window. However, there is one hack where you can use the PlacementTarget property of your context menu.

For details refer to this link - http://social.msdn.microsoft.com/Forums/nl/wpf/thread/526ab350-8788-4bc6-a98a-1e4dee6ad33a It contains exactly what you are trying to achieve here.

score 0 · Answer 3 · edited May 23 '17 at 12:30

0

Seems like here are answers for your question:

edited May 23 '17 at 12:30

Community

1
1

answered Jun 28 '12 at 08:57

Anatolii Gabuza

6,184
2
36
54

@AndersLindas Sorry, I have not realized that you are using `ContextMenu`. I updated the answer. – Anatolii Gabuza Jun 28 '12 at 09:03

Access my Window's DataContext inside a DataTemplate

3 Answers3