SfListView dragging issue when IsScrollingEnabled is set to false

[Stefan]

Hello Syncfusion Team,

I have a problem when dragging and dropping elements in a ListView where the property IsScrollingEnabled is set to "false". You can see all set properties below.

  <sf:SfListView

                    Grid.Row="2"

                    Grid.ColumnSpan="3"

                    AutoFitMode="Height"

                    DragItemTemplate="{StaticResource DraggingParameterDataTemplate}"

                    DragStartMode="OnHold"

                    IsScrollingEnabled="False"

                    ItemTemplate="{StaticResource ParameterDataTemplate}"

                    ItemsSource="{Binding Parameters}"

                    SelectionMode="None"

                    TapCommand="{Binding OpenParameterCommand, Mode=OneTime}">

                    <sf:SfListView.DragDropController>

                        <sf:DragDropController UpdateSource="True" />

                    </sf:SfListView.DragDropController>

                    <sf:SfListView.Behaviors>

                        <b:EventToCommandBehavior

                            Command="{Binding SetParameterOrderCommand, Mode=OneTime}"

                            EventArgsConverter="{StaticResource ForwardValueConverter}"

                            EventName="ItemDragging" />

                    </sf:SfListView.Behaviors>

                </sf:SfListView>

I have set IsScrollingEnabled to false because i have wrapped that list view in a scroll view with serveral other controls and layouts.

The problem occurs only after adding a new element. When I remove a new element, drag and drop is possible again.

Reproduction steps:

     1. initialize ObservableCollection with some entries.

          Result: Drag and Drop works.

     2. add a new element.

          Result: Drag and Drop does not work properly.

     3. delete an existing element.

          Result: Drag and Drop works.

     4. add a new element.

          Result: Drag and drop does not work properly.

     5. and so on.

Another interesting point is that this error only exists if IsScrollingEnabled="false".

Thanks for your great job.

[Lakshmi Natarajan]

Hi Stefan, 

 

Thank you for using Syncfusion products. 

 

We have checked the reported query “SfListView dragging issue when IsScrollingEnabled is set to false” from our end. We could reproduce the reported issue when loading the SfListView with IsScrollingEnabled as False inside the ScrollView. We are currently analyzing the issue in our source level and we will update you further details on or before November 4, 2020. We appreciate your patience until then.  

 

Regards, 

Lakshmi Natarajan 

 

[Lakshmi Natarajan]

Hi Stefan, 

 

Sorry for the inconvenience caused. 

 

We have analyzed the reported query in our source and drag and drop functions are executed property in our source as expected. On further analysis, the reported issue is a break from the Xamarin.Forms version v4.1.0.618606. We have already faced issues when loading the ListView with IsScrollingEnabled as false inside the ScrollView. We internally discussing with the development team regarding the same and raise query to Xamarin team. We will check and update you further details on November 6, 2020. We appreciate your patience until then. 

 

Regards, 

Lakshmi Natarajan 

[Lakshmi Natarajan]

Hi Stefan, 

 

Thank you for your patience. 

 

We have analyzed the reported scenario in our source and we would like to inform you that our drag and drop codes works fine as expected. Hence, we have logged the issue report to the Xamarin team and you can find the issue report from the following link, 

 

Bug report: https://github.com/xamarin/Xamarin.Forms/issues/12778 

 

Kindly follow up with the above issue report for further updates. Please let us know if you need further assistance. 

 

Regards, 

Lakshmi Natarajan