How to specify Command binding scope in MVVM?

Question

I'm messing around with MVVM and I've hit a bit of a roadblock with binding commands to buttons. I have a few buttons in a View ( = UserControl) that are generated based on a list of objects I have.

My code looks like this:

(MainWindow)

<ItemsControl ItemsSource="{Binding ViewModels}" Margin="12,57,12,12" />

(UserControl)

    <ItemsControl ItemsSource="{Binding AllConnections}" Margin="0,34,0,0">
        <ItemsControl.ItemTemplate>
            <DataTemplate>
                <Button Content="{Binding Password}" Height="23" HorizontalAlignment="Left" Margin="114,12,0,0" Name="button1" VerticalAlignment="Top" Width="75" Command="{Binding Path=ConnectCommand}" />
            </DataTemplate>
        </ItemsControl.ItemTemplate>
    </ItemsControl>

But ConnectCommand isn't being called and I assume it's because XAML is looking for it in the AllConnections binding, rather than the ViewModels binding where it should. How do I specify this?

Button Content="{Binding Password}" - is properly binded? – xZ6a33YaYEfmv Jan 07 '12 at 14:31 — xZ6a33YaYEfmv, Jan 07 '12 at 14:31

score 3 · Accepted Answer · answered Jan 07 '12 at 14:36

3

You should use Relative source to specify the ancestor. Something like this:

Command = "{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=ViewModel.CommandToBind}"

answered Jan 07 '12 at 14:36

ema

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yep. It's depends on how you set the datacontext on the view – ema Jan 07 '12 at 14:42

score 1 · Answer 2 · edited May 23 '17 at 11:53

1

You can add your command to Resources and just use {StaticResource yourCommand}. This could significally simplify xaml.

Useful links:
WPF Commands, How to declare Application level commands?
Commands as XAML Resources
MVVM Commanding inside of a datatemplate

edited May 23 '17 at 11:53

Community

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answered Jan 07 '12 at 22:01

Anatolii Gabuza

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How to specify Command binding scope in MVVM?

2 Answers2