Hierarchy and MVVM

[Roy Halvorsen]

I have a GridView that works fine, but now I have to expand the GridView to have a Details grid inside which have another datacontract then its parent GridView. The relation between the two datacontracts is an ID. I am using MVVM. I can not find anything about this in the documentation, so some examples or help would be much appreciated.

[Vlad]

Hello,

You can create additional property to return details data filtered by ID. You can check this post which is very similar to your case:
http://blogs.telerik.com/vladimirenchev/posts/09-10-16/how_to_silverlight_grid_hierarchy_load_on_demand_using_mvvm_and_ria_services.aspx

Sincerely yours,
Vlad
the Telerik team

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[Roy Halvorsen]

Thanks :-)
Exactly what I was looking for.

[Roy Halvorsen]

I was too quick...

How is this done when using properties in the ViewModel? I have tried the example in the blog, but it doesn't work for me. The child grid never loads any data. When expanding a row, shouldn't there be a proprty in the RadGrid telling the ViewModel that something has changed, and let me be able to get some id or index from the row that's been expanded? I tried RowLoaded, but that property is used when using codebehind and not MVVM.

[Vlad]

Hello Roy,

If the child collection in INotifyCollectionChanged (for example ObservableCollection<T>) the grid will display the data automatically.

Kind regards,
Vlad
the Telerik team

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[Roy Halvorsen]

Im not sure I get your answer correctly. Here is my RadGrid:

<telerik:RadGridView Name="rgvPatientNew"
    ItemsSource="{Binding Model}"
    RowIndicatorVisibility="Collapsed"
    CanUserFreezeColumns="False"
    IsFilteringAllowed="False"
    AutoGenerateColumns="False"
    ShowGroupPanel="False"
    IsReadOnly="True"
    SelectedItem="{Binding CurrentPatientNew, Mode=TwoWay}">
    <telerik:RadGridView.ChildTableDefinitions>
        <telerik:GridViewTableDefinition  />
    </telerik:RadGridView.ChildTableDefinitions>
    <telerik:RadGridView.Columns>
        <telerik:GridViewDataColumn Header="#" Width="70" DataMemberBinding="{Binding PasId}" IsVisible="True" />
        <telerik:GridViewDataColumn Header="FNr" Width="100" DataMemberBinding="{Binding OfficialId}" DataType="{x:Type System:String}" />
        <telerik:GridViewDataColumn Header="Navn" Width="200" DataMemberBinding="{Binding Name}" DataType="{x:Type System:String}" />
    </telerik:RadGridView.Columns>
    <telerik:RadGridView.HierarchyChildTemplate>
        <DataTemplate>
            <telerik:RadGridView IsReadOnly="True"
            AutoGenerateColumns="False"
            ItemsSource="{Binding ChildModel}"
            RowIndicatorVisibility="Collapsed"
            CanUserFreezeColumns="False"
            IsFilteringAllowed="False"
            ShowGroupPanel="False">
            <telerik:RadGridView.Columns>
                <telerik:GridViewDataColumn Header="#" Width="60" DataMemberBinding="{Binding PasId}" IsVisible="True" />
                <telerik:GridViewDataColumn Header="Id" Width="60" DataMemberBinding="{Binding WaitinglistId}" IsVisible="True" />
            </telerik:RadGridView.Columns>
            </telerik:RadGridView>
        </DataTemplate>
    </telerik:RadGridView.HierarchyChildTemplate>
</telerik:RadGridView>

And here is a part ov the ViewModel:

        private ObservableCollection<ModelDataContract> _Model;
        public ObservableCollection<ModelDataContract> Model
        {
            get { return _Model ?? (_Model = new ObservableCollection<ModelDataContract>()); }
        }

        public ObservableCollection<ChildModelDataContract> ChildModel
        {
            get
            {
                if (!childModelLoaded)
                {
                    int PasId = 10019848; //This should be tha ID from the Expanded Row

                    foreach (var myValye in UnityContainer.Resolve<IModelServiceAgent>().GetChildModels(PasId.ToString()))
                    {
                        ChildModel.Add(myValye);
                    }

                    childModelLoaded = true;
                }

                return ChildModel;
            }
        }

[Vlad]

Hi Roy,

ChildModel property should be on ModelDataContract class.

Best wishes,
Vlad
the Telerik team

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[Roy Halvorsen]

I'm not sure I understand what you mean about that. Can you give me an example?

[Vlad]

Hi,

You can find an example application attached.

Greetings,
Vlad
the Telerik team

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[Roy Halvorsen]

Thanks for your example, Vlad, but it doesn't help me much. All the DataContracts is within the Data Layer of the application, so I am not able to create the ChildModel property where you suggest.

[Vlad]

Hello Roy,

DataContracts is partial class you can extend it similar to what I've done in the blog post with RIA services.

All the best,
Vlad
the Telerik team

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Watch a video on how to optimize your support resource searches and check out more tips on the blogs.