Gong-wpf-dragdrop: Listbox horizontal line not showing
I can't figure it out why the gray horizontal line does not show when dragging items to ListBox. Is there some trick here?
<Window x:Class="EmptyListBoxWithDragAndDrop.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:gong="clr-namespace:GongSolutions.Wpf.DragDrop;assembly=GongSolutions.Wpf.DragDrop"
Title="MainWindow" Height="600" Width="800" WindowStartupLocation="CenterScreen">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<ListBox Grid.Column="0" ItemsSource="{Binding Source}"
gong:DragDrop.IsDragSource="True" gong:DragDrop.UseDefaultEffectDataTemplate="True"/>
<ListBox Grid.Column="1" ItemsSource="{Binding Target}"
gong:DragDrop.IsDropTarget="True" gong:DragDrop.DropHandler="{Binding}">
<ListBox.Style>
<Style TargetType="ListBox" BasedOn="{StaticResource {x:Type ListBox}}">
<Style.Triggers>
<Trigger Property="HasItems" Value="False">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<TextBlock Text="Drag items from left ListBox" VerticalAlignment="Center" HorizontalAlignment="Center"/>
</ControlTemplate>
</Setter.Value>
</Setter>
</Trigger>
</Style.Triggers>
</Style>
</ListBox.Style>
</ListBox>
</Grid>
</Window>
I even remove the trigger style, but it doesn't work, no horizontal line is shown.
This is the line I'm talking about:
JobaDiniz
All 7 comments
@JobaDiniz If a ItemsControl is empty no DropTargetInsertionAdorner will be shown.
punker76
on 25 Aug 2016
But it is not empty, here is the sample.
JobaDiniz
on 25 Aug 2016
@JobaDiniz :-D I should use a default for this to avoid such issues...
public void DragOver(IDropInfo dropInfo)
{
// you must say which adorner you want if you implement the IDropTarget interface
dropInfo.DropTargetAdorner = DropTargetAdorners.Insert;
// or you call the DragOver method from the default DefaultDropHandler to get the adorner
//GongSolutions.Wpf.DragDrop.DragDrop.DefaultDropHandler.DragOver(dropInfo);
if (dropInfo.Data is string)
dropInfo.Effects = System.Windows.DragDropEffects.Copy;
}
punker76
on 25 Aug 2016
@JobaDiniz And you should give your custom template a background to allow target drop at the whole client size
<ControlTemplate>
<Grid Background="{TemplateBinding Background}">
<TextBlock Text="Drag items from left ListBox" VerticalAlignment="Center" HorizontalAlignment="Center"/>
</Grid>
</ControlTemplate>
Is there some trick here?
So there is a catch :D Thanks, it worked!
And you should give your custom template a background to allow target drop at the whole client size
I can't believe it! Thanks a lot, I've been banging my head over this (my stackoverflow question)
JobaDiniz
on 25 Aug 2016
@JobaDiniz Just answered ;-)
I will add a new attached property to allow showing the target adorner on empty ItemsControls.
ShowDropAdornerOnEmptyTarget
or is there a better name?
punker76
on 25 Aug 2016
I will add a new attached property to allow showing the target adorner on empty ItemsControls
I don't know if this is really required. My issue was something else.
JobaDiniz
on 25 Aug 2016
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Most helpful comment
So there is a catch :D Thanks, it worked!
I can't believe it! Thanks a lot, I've been banging my head over this (my stackoverflow question)