CODEWITHSUNDEEP
c#wpfmvvmbindingdatacontext
Cagaya Coper
Cagaya Coper

Reputation: 75

Access userctrol's datacontext does not work for me

In wpf mvvm mode, i have a usercontrol like this

<UserControl  MyControl>
  <Grid>
    <DataGrid
       ItemsSource="{Binding MySource}"         
       Visibility = "{Binding the usercontrol's datacontext.UserGrade}"
    />
  </Grid>
</UserControl>

In my MainPageView I use it like this

<Window:MainPageView
   xmlns:vm="clr-namespace:My.ViewModel"
   xmlns:userCtl="clr-namespace:My.Controls"
   <Window.DataContext>
     <vm:MainPageViewModel/>
   </Window.DataContext>
   <userCtl:MyControl>
     <userCtl:Mycontrol.DataContext>
        <vm:MyControlViewModel/>
     </userCtl:Mycontrol.DataContext>
   <userCtl:MyControl>
</Window:MainPageView>

Now here's the question, how can I access the MyUserControl's datacontext.UserVisiable, and binding to the MyUserControl's datagrid visibility? I tried to use {RelativeSource FindAncestor, AncestorType={x:Type UserControl}} but it did not work, or I didi it wrong? Thanks!

Upvotes: 0

Views: 81

Answers (1)

Lupu Silviu
Lupu Silviu

Reputation: 1165

You could try this:

        <Grid>
        <DataGrid ItemsSource="{Binding MySource}"    
                  Visibility = "{Binding DataContext.UserGrade, RelativeSource={RelativeSource AncestorType=UserControl}}"/>
    </Grid>

Explanation: Using RelativeSource for the Binding Source, helps you navigate throw the visual tree, to the first ancestor of the current control, of the type specified (UserControl). It then uses the UserControl.DataContext.UserGrade as the binding property.

If the Usercontrol.DataContext is null, then the binding will not work. As specified in the question, userControl has a DataContext that contains that property.

Also, you could try setting the AncestorType=location:MyControl, in case UserControl is not enough. (location: is the namespace where your control is located)

Upvotes: 0

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