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Drag & drop and Hierarchy

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GridView

This is a migrated thread and some comments may be shown as answers.

7 Answers, 1 is accepted

answered on 21 Jan 2016, 02:45 PM

Hello Wang,

In general, this requirement can be achieved by setting the AllowDrop property of a given GridViewRow to "False". I suggest you taking a look at the Drag and Drop within RadGridView help topic. If you review the OnRowDragOver event handler method, you will notice that the sender object is the currently dragged row. So, you can implement custom logic depending on whether a given row is an item of the parent collection or the child one, and set its AllowDrop property as per your requirements.

Hope this helps.

All the best,
Stefan X1
Telerik

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answered on 25 Jan 2016, 05:23 PM

Hello Wang,

Can you please share some details on the difficulties you are experiencing at your end? Basically, you need to set the AllowDrop property of the hierarchical grid to "True" and apply a Style targeting its GridViewRow elements that sets the AllowDrag property to "True". You need to also ensure, that you have enabled the RowReorderBehavior for the hierarchical grid, as demonstrated in the article I referred to in my previous post.

You can also check out the relevant SDK Example using the SDK Samples Browser.

Best Regards,
Stefan X1
Telerik

answered on 01 Feb 2016, 04:36 AM

Hello Stefan X1,

I tried to set the AllowDrop property and set row AllowDrop property in OnRowDragOver event,

there's no DropPositionFeedback when I DragOver a child to anther child, but it can be shown when I drag a parent to anther parent.

here is my xaml code:

<telerik:RadGridView x:Name="StageGrid" GroupRenderMode="Flat"

SelectionMode="Extended"

CanUserFreezeColumns="False" ColumnWidth="*"

ItemsSource="{Binding StageCollection}"

GridLinesVisibility="None" RowIndicatorVisibility="Collapsed"

AutoGenerateColumns="False" IsFilteringAllowed="False"

ShowGroupPanel="False" SelectionChanged="StageGrid_SelectionChanged"

AllowDrop="True" behavior:RowReorderBehavior.IsEnabled="True">

<telerik:RadGridView.Resources>

<DataTemplate x:Key="DraggedItemTemplate">

<StackPanel>

<TextBlock Text="{Binding CurrentDraggedItem.Name}" FontWeight="Bold" />

</StackPanel>

</DataTemplate>

<converter:IntegerToBooleanConverter x:Key="integerToBooleanConverter" />

</telerik:RadGridView.Resources>

<telerik:RadGridView.RowStyle>

<Style TargetType="telerik:GridViewRow">

<Setter Property="telerik:DragDropManager.AllowDrag"

Value="True" />

<Setter Property="telerik:DragDropManager.TouchDragTrigger"

Value="TapAndHold"/>

<Setter Property="IsExpandable" Value="True"/>

<Style.Triggers>

<DataTrigger Binding="{Binding Converter={StaticResource integerToBooleanConverter}, Path=SubList.Count}" Value="False">

<Setter Property="IsExpandable" Value="False"/>

</DataTrigger>

</Style.Triggers>

</Style>

</telerik:RadGridView.RowStyle>

<telerik:RadGridView.Columns>

<custom:NumberColumn Header="Nummber" Width="auto" ></custom:NumberColumn>

<telerik:GridViewDataColumn DataMemberBinding="{Binding Name}" Header="Name" />

</telerik:RadGridView.Columns>

<telerik:RadGridView.ChildTableDefinitions>

<telerik:GridViewTableDefinition />

</telerik:RadGridView.ChildTableDefinitions>

<telerik:RadGridView.HierarchyChildTemplate>

<DataTemplate>

<telerik:RadGridView x:Name="SectionGrid" GroupRenderMode="Flat"

GridLinesVisibility="None" CanUserFreezeColumns="False" AutoGenerateColumns="False" ShowGroupPanel="False" IsFilteringAllowed="False" ItemsSource="{Binding SubList}" AllowDrop="True"

behavior:RowReorderBehavior.IsEnabled="True">

<telerik:RadGridView.Resources>

<DataTemplate x:Key="DraggedItemTemplate">

<StackPanel>

<TextBlock Text="{Binding CurrentDraggedItem.Name}" FontWeight="Bold" />

</StackPanel>

</DataTemplate>

<converter:IntegerToBooleanConverter x:Key="integerToBooleanConverter"/>

</telerik:RadGridView.Resources>

<telerik:RadGridView.RowStyle>

<Style TargetType="telerik:GridViewRow">

<Setter Property="telerik:DragDropManager.AllowDrag" Value="True" />

<Setter Property="telerik:DragDropManager.TouchDragTrigger" Value="TapAndHold"/>

<Setter Property="IsExpandable" Value="True"/>

<Style.Triggers>

<DataTrigger Binding="{Binding Converter={StaticResource integerToBooleanConverter}, Path=SubList.Count}" Value="False">

<Setter Property="IsExpandable" Value="False"/>

</DataTrigger>

</Style.Triggers>

</Style>

</telerik:RadGridView.RowStyle>

<telerik:RadGridView.Columns>

<telerik:GridViewDataColumn DataMemberBinding="{Binding Name}"

Header="Name" />

<telerik:GridViewDataColumn DataMemberBinding="{Binding Size}"

Header="Size(mm)" />

<telerik:GridViewDataColumn DataMemberBinding="{Binding SumSize}"

Header="SumSize(mm)" />

</telerik:RadGridView.Columns>

</telerik:RadGridView>

</DataTemplate>

</telerik:RadGridView.HierarchyChildTemplate>

</telerik:RadGridView>

answered on 03 Feb 2016, 02:14 PM

Hi Wang,

Can you please clarify whether you are referring to the symbol appearing over a given element, to which the drop operation is disabled? If this is the case, please note, that if the AllowDrop property is correctly set to a given GridViewRow, this symbol would appear automatically. Basically, within the DragOver event handler, you can use the DataContext of a given GridViewRow to determine whether the item is from the child or the parent collection, thus set the AllowDrop property accordingly.

Best Regards,
Stefan X1
Telerik