VirtualQueryableCollectionView custum grouping

[Josef]

I have my custom VirtualQueryableCollectionView to connect to my database.
I can read data an sorting. Now i would like to do grouping. When i drag and drop column to group panel to group by this column it creates one group expander with null value. When i expand this expander there is all my grid row.
Can you help me how can i create my custom grouping?

Thanks Josef.

public class VirtualQuery : VirtualQueryableCollectionView
   {

       WPF.Models.VirtualQuery _cacheVirtualQuery;
       CacheConnection _conn;
       public VirtualQuery(WPF.Models.VirtualQuery cacheVirtualQuery)
       {
           LoadSize = 1000;
           _cacheVirtualQuery = cacheVirtualQuery;
           _conn = cacheVirtualQuery.Connection;
           _cacheVirtualQuery.CreateQuery();
           VirtualItemCount = Convert.ToInt16(_cacheVirtualQuery.VirtualItemCount);
           ItemsLoading += VirtualQuery_ItemsLoading;
       }


       private void VirtualQuery_ItemsLoading(object sender, VirtualQueryableCollectionViewItemsLoadingEventArgs e)
       {
           SetUpCacheQuery();
           _cacheVirtualQuery.ItemsLoading(e.StartIndex, e.ItemCount);
           VirtualItemCount = Convert.ToInt16(_cacheVirtualQuery.VirtualItemCount);
           #region smazat dynamicky objekt pomale
           /*CacheDynamicObject[] DataContext = new CacheDynamicObject[_cacheVirtualQuery.QueryItems.Count] ;
           for (int i = 0; i < _cacheVirtualQuery.QueryItems.Count; i++)
           {
               DataContext[i] = new CacheDynamicObject(_cacheVirtualQuery.QueryItems[i] as CacheArrayOfDataTypes);
           }*/
           #endregion
           object[] DataContext1 = new object[_cacheVirtualQuery.QueryItems.Count];
           for (int i = 0; i < _cacheVirtualQuery.QueryItems.Count; i++)
           {
               DataContext1[i] = new Dictionary<string, string>(_cacheVirtualQuery.QueryItems[i] as CacheArrayOfDataTypes); ;
           }
           Load(e.StartIndex, DataContext1);
           _cacheVirtualQuery.QueryItems.Clear();
           _cacheVirtualQuery.Connection.ForceSync();
       }

       private void SetUpCacheQuery()
       {
           _cacheVirtualQuery.SortDescriptors.Clear();
           foreach (Telerik.Windows.Controls.GridView.ColumnSortDescriptor item in SortDescriptors)
           {
               WPF.Models.SortDescriptor desc = new WPF.Models.SortDescriptor(_conn);
               desc.SortUniqueName =  item.Column.UniqueName;
               desc.SortDirection = item.SortDirection.ToString();
               _cacheVirtualQuery.SortDescriptors.Add(desc);
           }
       }
   }

grouping?

[Vlad]

Hello,

 Grouping with virtual collection is supported only when you provide IQueryable in the collection constructor. Loading groups/items using Load()/ItemsLoading is not supported. 

Greetings,
Vlad
the Telerik team

[Josef]

Thank you for your answer.
Is any idea, suggest or sample how implement IQueryable? I want to implemented IQueryable but i don't know how?

Josef.

[Milan]

Hello Josef,

You can find more information about Data Virtualization here. Regarding IQueryable, you can use Entity Framework context which is IQueryable and will allow you to have group, page, sort, filter on the server. 

// Entity Framework context
var context = new NorthwindEntities();
           var query = context.Order_Details.OrderBy(o => o.OrderID);
           var view = new VirtualQueryableCollectionView(query) { LoadSize = 10 };

Kind regards,
Milan
the Telerik team