All groups become collapsed after applying the filter.

[Burkhard Morgeneyer]

I use the Excel filter.

WithEvents gdf As New GridExcelFilter

After I apply the filter, all my open groups become collapsed.

Is there a way to keep the original group state, after the filter is applied?

Should I also use Serialization/Deserialization to store and restore the group state?

Which event should I use to achieve this?

The gridexcelfilter has to events.

[Mohanraj Gunasekaran]

Hi Burkhard, 

Thanks for using Syncfusion product. 

Yes, you can use serialization/deserialization to maintain the group state after filtering the records and this can be achieved by using RecordFilterItemChanging, RecordFilterItemChanged of GridExcelFilter and CategorizedRecords event. Please refer to the below code example, 

Code example 

Dim filter As New GridExcelFilter() 

AddHandler filter.RecordFiltersItemChanging, AddressOf filter_RecordFiltersItemChanging 

AddHandler filter.RecordFiltersItemChanged, AddressOf filter_RecordFiltersItemChanged 

AddHandler Me.gridGroupingControl1.CategorizedRecords, AddressOf gridGroupingControl1_CategorizedRecords 

 

Private IsRecordFilterItemChanged As Boolean = False 

Private Sub gridGroupingControl1_CategorizedRecords(ByVal sender As Object, ByVal e As Syncfusion.Grouping.TableEventArgs) 

            'Deserilize the GroupExpandState after complte the record filtering. 

    If IsRecordFilterItemChanged Then 

       DeserializeExpandState() 

       IsRecordFilterItemChanged = False 

    End If 

End Sub 

 

Private Sub filter_RecordFiltersItemChanged(ByVal sender As Object, ByVal e As Syncfusion.Collections.ListPropertyChangedEventArgs) 

            If e.Action = Syncfusion.Collections.ListPropertyChangedType.Add OrElse e.Action = Syncfusion.Collections.ListPropertyChangedType.Insert Then 

                IsRecordFilterItemChanged = True 

            End If 

End Sub 

 

Private Sub filter_RecordFiltersItemChanging(ByVal sender As Object, ByVal e As Syncfusion.Collections.ListPropertyChangedEventArgs) 

     If e.Action = Syncfusion.Collections.ListPropertyChangedType.Add OrElse e.Action = Syncfusion.Collections.ListPropertyChangedType.Insert Then 

         SerializeExpandState() 

     End If 

End Sub 

 

Private Sub SerializeExpandState() 

 

  'Serialize the expanded records before change the data source.  

  Dim groupExpandState As New List(Of GroupExpandState)() 

   For Each g As Syncfusion.Grouping.Group In Me.gridGroupingControl1.Table.TopLevelGroup.Groups 

        If g.IsExpanded Then 

           groupExpandState.Add(New GroupExpandState() With {.GroupIdentifier = g.UniqueGroupId(0).ToString(), .IsExpanded = g.IsExpanded}) 

        End If 

    Next g 

 

 Dim xw As New XmlTextWriter("GroupsExpandState.xml", System.Text.Encoding.UTF8) 

  Dim serializer As New XmlSerializer(GetType(List(Of GroupExpandState))) 

  serializer.Serialize(xw, groupExpandState) 

  xw.Close() 

End Sub 

 

Private Sub DeserializeExpandState() 

   'Deserialize the expanded records after changed the source. 

   Dim xr As XmlReader = New XmlTextReader("GroupsExpandState.xml") 

   Dim deserializer As New XmlSerializer(GetType(List(Of GroupExpandState))) 

   Dim expandState As List(Of GroupExpandState) = TryCast(deserializer.Deserialize(xr), List(Of GroupExpandState)) 

 

   For Each groupExpand As GroupExpandState In expandState 

        Dim groupIndex As Integer = Me.gridGroupingControl1.Table.TopLevelGroup.Groups.FindGroup(groupExpand.GroupIdentifier) 

        If groupIndex > -1 Then 

                    Me.gridGroupingControl1.Table.TopLevelGroup.Groups(groupIndex).IsExpanded = True 

        End If 

   Next groupExpand 

 

   Me.gridGroupingControl1.TableControl.Refresh() 

End Sub 

 

 

Sample link: GridGroupingControl 

 

Please let us know if you have any concerns. 

 

Regards, 

Mohanraj G