Issue that combobox with VirtualQueryableCollectionView in RadGridView

[Deng]

Hi Guys,

I am very interested with Data virtualization, so I am refractoring my customer's old WPF project. Everything goes well but I encountered one critical issue when I use combobox with VirtualQueryableCollectionView  as GridViewDataColumn.CellEditTemplate.  Let me show it:

1. I make below collection binding to my combobox

private VirtualQueryableCollectionView _dataSource;

public VirtualQueryableCollectionView DataSource

{

    get

    {

        if (_dataSource == null)

        {

            _dataSource = new VirtualQueryableCollectionView(Manager.GetAll().AsQueryable()

                .OrderBy(ExpressionHelper.CreateOrderByExpression<T>(DisplayName)))

            {

                LoadSize = 20,

                VirtualItemCount = _manager.GetCount(),

            };

            //_dataSource.ItemsLoading += ItemsLoading;

            //_dataSource.ItemsLoaded += ItemsLoaded;

        }

        return _dataSource;

    }

    set

    {

        if (Equals(_dataSource, value)) return;

        _dataSource = value;

        OnPropertyChanged("DataSource");

    }

}
2. I used GridViewDataColumn.CellEditTemplate with below 

<telerik:GridViewDataColumn Header="{common:Translate RetailChain}"
                                           x:Name="Test"
                                           DataMemberBinding="{Binding BuyingOrganization.BO_CompanyName}">
                   <telerik:GridViewDataColumn.CellEditTemplate>
                       <DataTemplate>
                           <telerik:RadComboBox ToolTip="{common:Translate RetailChain_TT}"
                                                SelectedValue="{Binding BuyingOrganization}"
                                                ItemsSource="{Binding Source={StaticResource GlobalDataManager},Path= BuyingOrganizations.DataSource}"
                                                DisplayMemberPath="{Binding Source={StaticResource GlobalDataManager},Path= BuyingOrganizations.DisplayName}" />
                       </DataTemplate>
                   </telerik:GridViewDataColumn.CellEditTemplate>
               </telerik:GridViewDataColumn>

3. when I change inner combobox's selection, my viewmodel BuyingOrganization can be changed. From surface,
 it work right.   But if I take this cell out of Edit mode, the Null will be set to this BuyingOrganization. 

I debug it, the VirtualQueryableCollectionView will call MoveCurrentPosition to one null value.

How should I do? Can you give me some tips?

Thanks & Regards

Dely

[Deng]

Hi Guys,

I am very interested with Data virtualization, so I am refractoring my customer's old WPF project. Everything goes well but I encountered one critical issue when I use combobox with VirtualQueryableCollectionView  as GridViewDataColumn.CellEditTemplate.  Let me show it:

1. I make below collection binding to my combobox

private VirtualQueryableCollectionView _dataSource;

public VirtualQueryableCollectionView DataSource

{

    get

    {

        if (_dataSource == null)

        {

            _dataSource = new VirtualQueryableCollectionView(Manager.GetAll().AsQueryable()

                .OrderBy(ExpressionHelper.CreateOrderByExpression<T>(DisplayName)))

            {

                LoadSize = 20,

                VirtualItemCount = _manager.GetCount(),

            };

            //_dataSource.ItemsLoading += ItemsLoading;

            //_dataSource.ItemsLoaded += ItemsLoaded;

        }

        return _dataSource;

    }

    set

    {

        if (Equals(_dataSource, value)) return;

        _dataSource = value;

        OnPropertyChanged("DataSource");

    }

}




2. I used GridViewDataColumn.CellEditTemplate with below 

<telerik:GridViewDataColumn Header="{common:Translate RetailChain}"

                                           x:Name="Test"

                                           DataMemberBinding="{Binding BuyingOrganization.BO_CompanyName}">

                   <telerik:GridViewDataColumn.CellEditTemplate>

                       <DataTemplate>

                           <telerik:RadComboBox ToolTip="{common:Translate RetailChain_TT}"

                                                SelectedValue="{Binding BuyingOrganization}"

                                                ItemsSource="{Binding Source={StaticResource GlobalDataManager},Path= BuyingOrganizations.DataSource}"

                                                DisplayMemberPath="{Binding Source={StaticResource GlobalDataManager},Path= BuyingOrganizations.DisplayName}" />

                       </DataTemplate>

                   </telerik:GridViewDataColumn.CellEditTemplate>

               </telerik:GridViewDataColumn>




3. when I change inner combobox's selection, my viewmodel BuyingOrganization can be changed. From surface,
 it work right.   But if I take this cell out of Edit mode, the Null will be set to this BuyingOrganization. 

I debug it, the VirtualQueryableCollectionView will call MoveCurrentPosition to one null value.

How should I do? Can you give me some tips?

Thanks & Regards

Dely

[Deng]

Hi,

I think I found the solution for this. The reason of this behavior is VirtualQueryableCollectionView  will manage the Current Item automatically. Because I use repository and unitofwork, so radcombobox's selectValve binding item will related VirtualQueryableCollectionView 's underlying data(DBcontext). So VirtualQueryableCollectionView ' current item
change will affect selection value. I fixed it as disable VirtualQueryableCollectionView  CurrentItemChange behavior, below:


            /// <summary>
            /// The reason I add this , VirtualQueryableCollectionView will change inner current item, 
            /// this behavior will make our selection in UI uselessly 
            /// </summary>
            /// <param name="sender"></param>
            /// <param name="e"></param>
            void CurrentChanging(object sender, CurrentChangingEventArgs e)
            {
                if (e.IsCancelable)
                    e.Cancel = true;
            }

[Dimitrina]

Hello,

Thank you for sharing your solution with the community. 

Kind regards,
Didie
the Telerik team