ListBoxDropTarget-如何获取放置位置索引? [英] ListBoxDropTarget - How do I get a drop location index?

问题描述

好，

我整天都在战斗-无济于事...

我在Silverlight中有一个ListBox，我想赋予用户通过拖放进行重新排序的能力.所以我想我会很聪明，并利用Microsoft Silverlight工具箱ListBoxDropTarget控件来实现魔术.

基本上，除了确定在哪里放置项目的索引(它在同一listBox中被重新排序)之外，我都能按照我期望的方式工作.

如何生成(或捕获)放置位置/(的索引)以对列表框重新排序?

样品-会很有帮助...

这是XAML:

Ok,

I have been fight''n this all day - to no avail...

I have a ListBox in Silverlight that I would like to give the user the ability to reorder via drag and drop.. So I thought I would be smart and leverage the Microsoft Silverlight toolkit ListBoxDropTarget control to do the magic.

Basically, I have everything working the way I would expect except for identifying the index where to drop the item (It''s being reordered in the same listBox).

How can I generate (or capture) the drop location / (index of) to reorder the listbox?

Samples - would be helpful...

Here is the XAML:

<toolkit:ListBoxDragDropTarget x:Name="dropTarget" AllowDrop="True">
                        <i:Interaction.Triggers>
                            <i:EventTrigger EventName="ItemDragCompleted">
                                <GalaSoft_MvvmLight_Command:EventToCommand Command="{Binding ReOrderCommand}" CommandParameter="{Binding ElementName=dropTarget.ItemDragEventArgs}" PassEventArgsToCommand="True"></GalaSoft_MvvmLight_Command:EventToCommand>
                            </i:EventTrigger>
                        </i:Interaction.Triggers>
                        <ListBox x:Name="listQueries" AllowDrop="True" ItemsSource="{Binding AllQueries}" ScrollViewer.VerticalScrollBarVisibility="Auto" Style="{StaticResource stlListBox}" Height="Auto" Width="363">
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <StackPanel Orientation="Horizontal"  HorizontalAlignment="Stretch">
                                        <CheckBox IsChecked="{Binding IsVisible}" ToolTipService.ToolTip="Check/Uncheck to show/hide this queries results" VerticalAlignment="Top"></CheckBox>
                                        <Button Content="+" Command="{Binding ShowQueryCommand}" VerticalAlignment="Top" />
                                            <StackPanel Orientation="Vertical">
                                                <TextBlock Text="{Binding QueryName}" />
                                                <StackPanel Visibility="{Binding IsOpen,Mode=TwoWay, Converter={StaticResource BoolToVisibilityConverter}}" >
                                                    <TextBlock Text="{Binding QueryStringForPanel}" TextWrapping="Wrap" />
                                                </StackPanel>
                                            </StackPanel>
                                        <Button x:Name="btnDelete" Content="X" Style="{StaticResource stlListBoxDeleteButton}" 

                                            Command="{Binding Path=DataContext.DeleteQueryCommand, ElementName=listQueries}" CommandParameter="{Binding}" HorizontalAlignment="Right" VerticalAlignment="Top">
                                        </Button>
                                        <UC:ComboColorpicker  Grid.Column="1" Grid.Row="1"  selectedColor="{Binding HightlightColour, Mode=TwoWay}" Margin="5,0,0,0"/>
                                    </StackPanel>

                                </DataTemplate>
                            </ListBox.ItemTemplate>
                        </ListBox>
                    </toolkit:ListBoxDragDropTarget>

//And here is the code from my ViewModel:


 private void ReOrder(System.Windows.Controls.ItemDragEventArgs LBDDT)
        {

        //**** --- how do we get the index -- for the drop location????
            int myIndx = 0;

            var tmp = (LBDDT.DragSource as System.Windows.Controls.ListBox).ItemsSource.Cast<MyClass>().ToList();

            SelectionCollection selCollection = LBDDT.Data as SelectionCollection;

            MyClass qvm = selCollection[0].Item as MyClass;

	//**** get current index
            int idx = tmp.IndexOf(qvm);
   

	//**** if I manually set the index -- it works fine...  --Just need to understand how to dynamically generate the drop location index
            myIndx = idx - 1;

	//**** AllResults is the collection of MyClass that the LsitBox is bound to...   --Again - this works if I hard code the drop index...  How do I get the drop Index location for reordering? 

            AllResults.Remove(qvm);
            AllResults.Insert(myIndx, qvm);

        }

推荐答案

似乎工具箱ListBoxDragDropControl使用ListBox.ItemsPanel来放置" ...如果您将ListBox.ItemTemplate与DataTemplate一起使用您必须添加ListBox.ItemsPanel才能使控件正常工作.

Appears that the toolkit ListBoxDragDropControl uses a ListBox.ItemsPanel to "drop"... If you are using a ListBox.ItemTemplate with a DataTemplate you must add a ListBox.ItemsPanel for the control to work.

<ListBox x:Name="myListBox" AllowDrop="True" ItemsSource="{Binding BindSource}">
                            <ListBox.ItemsPanel>
                                <ItemsPanelTemplate>
                                    <StackPanel Orientation="Vertical"/>
                                </ItemsPanelTemplate>
                            </ListBox.ItemsPanel>
                            <ListBox.ItemTemplate>
                                <DataTemplate> MY-DATA - STUFF </DataTemplate>
                            <ListBox.ItemTemplate>
                           </ListBox>

这篇关于ListBoxDropTarget-如何获取放置位置索引?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！