无法清除WPF ListBox.SelectedItems集合 [英] can't clear WPF ListBox.SelectedItems collection
问题描述
我似乎无法清除要绑定的WPF ListBox的SelectedItems集合.我尝试调用ListBox.SelectedItems.Clear()，尝试将SelectedIndex设置为-1，将SelectedItem设置为null并调用ListBox.UnselectAll().在调试时，似乎没有执行分配任务或正在重置SelectedItems集合，但是我不确定是什么.我在SelectionChanged回调中添加了一个断点，它从未被意外击中，但是SelectedItems.Count成员始终至少为1(由于此ListBox的选择模式为MultiExtended，因此有时大于1).
I can't seem to get the SelectedItems collection of a data bound WPF ListBox to clear. I've tried calling ListBox.SelectedItems.Clear(), i've tried setting the SelectedIndex to -1, setting the SelectedItem to null and calling ListBox.UnselectAll(). While debugging it appears that either the assignments don't take or something is resetting the SelectedItems collection, but I'm not sure what. I put a breakpoint in the SelectionChanged callback and it never gets hit unexpectedly yet the SelectedItems.Count member is always at least 1 (sometimes more than 1 since this ListBox's selection mode is MultiExtended).
有人以前看过这个吗，知道我在做什么错吗?这个问题似乎与这个问题完全相同: WPF-如何清除ListView中的选择?
Has anyone seen this before and know what I'm doing wrong? This question is seemingly exactly the same as this one: WPF - How to clear selection from ListView?
除了那篇文章，Sonny Boy使用的是ListView，而我使用的是ListBox.无论如何，投票的答案是调用ListView.UnselectAll()，在我的情况下不起作用.
except in that post, Sonny Boy is using a ListView and I'm using a ListBox. In any case, the voted upon answer was to call ListView.UnselectAll() which doesn't work in my case.
我觉得我肯定在做一些很明显的错误，因为清除选择应该很简单.
I feel like I must be doing something very obviously wrong as clearing the selection should be pretty straight forward.
注意:明确一点，我不想从列表框中删除选择，我只是不想选择任何内容.
NOTE: Just to be clear, I don't want to remove the selections from the ListBox, I just want nothing to be selected.
谢谢！
<ListBox Background="{StaticResource ResourceKey=DarkGray}" Name="lbx_subimageThumbnails" Margin="6,6,6,0" ItemsSource="{Binding ElementName=lbx_thumbnails, Path=SelectedItem.Swatches}" Style="{StaticResource WPTemplate}" SelectionMode="Extended" Height="{Binding ElementName=sld_swatchRows, Path=Value}" VerticalAlignment="Top" SelectionChanged="lbx_subimageThumbnails_SelectionChanged" DataContext="{Binding}">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel HorizontalAlignment="Stretch" />
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Setter Property="Visibility" Value="{Binding Path=Vis}" />
</Style>
</ListBox.ItemContainerStyle>
<ListBox.ItemTemplate>
<DataTemplate>
<Grid Width="270" Height="270" Margin="5,5,5,5" Tag="{Binding}" Name="lbx_swatchThumbnail" Background="{StaticResource ResourceKey=LightGray}" PreviewMouseLeftButtonDown="lbx_swatchThumbnail_PreviewMouseLeftButtonDown" PreviewMouseMove="lbx_swatchThumbnail_PreviewMouseMove">
<Grid.LayoutTransform>
<ScaleTransform CenterX="0" CenterY="0" ScaleX="0.50" ScaleY="0.50" />
</Grid.LayoutTransform>
<Grid.ContextMenu>
<ContextMenu>
<MenuItem Header="Sync selected" Click="btn_syncSwatch_Click" />
<MenuItem Header="Re-export selected" Click="btn_exportSelected_Click"/>
<MenuItem Header="Set as default thumbnail" Click="btn_setThumbnail_Click"/>
<MenuItem Header="Delete selected" Click="btn_deleteSwatch_Click"/>
<MenuItem Header="Show in Explorer" Click="mnu_showSwatchesInExplorer_Click" />
<MenuItem Header="Create Frames" Click="mnu_createFrames_Click" ToolTip="Creates FRAMEs groups to your PSD file under the Group associated with the selected swatch. DO NOT RE-ORDER OR RENAME THE GENERATED groups!" />
<MenuItem Header="Create MIPs" Click="mnu_createMIPs_Click" ToolTip="Creates MIPs groups to your PSD file under the Group associated with the selected swatch. DO NOT RE-ORDER OR RENAME THE GENERATED groups!" />
</ContextMenu>
</Grid.ContextMenu>
<Border BorderBrush="Black" BorderThickness="1">
<Grid ToolTip="{Binding Path=Texture}">
<Image VerticalAlignment="Center" HorizontalAlignment="Center" PhotoLoader:Loader.DisplayOption="Preview" PhotoLoader:Loader.DisplayWaitingAnimationDuringLoading="True" PhotoLoader:Loader.Source="{Binding Path=Texture}" PhotoLoader:Loader.DisplayErrorThumbnailOnError="True" Width="256" Height="256" />
<TextBlock VerticalAlignment="Top" HorizontalAlignment="Center" Margin="0,10,0,0" FontSize="20" Text="{Binding Path=Group}" Background="Black" Foreground="White"/>
<TextBlock VerticalAlignment="Bottom" HorizontalAlignment="Center" Background="Black" Margin="0,0,0,10" FontSize="20" Foreground="White">
<TextBlock.Text>
<MultiBinding StringFormat="{}{0} x {1} {2}" >
<Binding Path="Width" />
<Binding Path="Height" />
<Binding Path="Format" />
</MultiBinding>
</TextBlock.Text>
</TextBlock>
</Grid>
</Border>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
// this callback kicks everything off.
private void btn_editSwatch_Click(object sender, RoutedEventArgs e)
{
// get a list of the selected indices - we will have to unselect the texture source and reselect it after the re-export in order to force the thumbnail display to update
// so we will save a list of indices to reselect them after the export
List selectedIndices = new List();
for (int i = 0; i < lbx_subimageThumbnails.Items.Count; i++)
{
if (lbx_subimageThumbnails.SelectedItems.Contains(lbx_subimageThumbnails.Items[i]))
{
selectedIndices.Add(i);
}
} // store the index of the selected texture source to reselect it after the re-export
int selIndex = lbx_thumbnails.SelectedIndex;
// edit and re-export the selected thumbnails
if (this.EditThumbnails(lbx_subimageThumbnails.SelectedItems, lbx_thumbnails.SelectedItem))
{
// re-select the texture source
lbx_thumbnails.SelectedIndex = selIndex;
// re-select the previously selected thumbnails.
foreach (int index in selectedIndices)
{
if (!lbx_subimageThumbnails.SelectedItems.Contains(lbx_subimageThumbnails.Items[index]))
{
lbx_subimageThumbnails.SelectedItems.Add(lbx_subimageThumbnails.Items[index]);
}
}
}
}
private void lbx_subimageThumbnails_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ListBox textureSelector = sender as ListBox;
if (textureSelector != null)
{
//update some UI elements
}
}
/*
this is the SelectionChanged callback for another listbox which is bound as the ItemSource of lbx_subimageThumbnails. When the selection here changes, we default the selection of the subimage listbox to the first subimage after first clearing the selected items in the subimage listbox
*/
private void lbx_thumbnails_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
// clear the previous swatch selection and select the first thumbnail
// None of these methods works. after each, lbx_subimageThumbnails.SelectedItems.Count is still >= 1
// Also, trying to set the SelectedIndex doesn't take. After the assignment, debugger shows
// SelectedIndex is still 0
lbx_subimageThumbnails.SelectedIndex = -1;
lbx_subimageThumbnails.SelectedIndex = -1;
// Trying to set SelectedItem to null doesn't work...after assignment, SelectedItem is still a vaild
// reference
this.lbx_subimageThumbnails.SelectedItem = null;
if (lbx_subimageThumbnails.SelectedItems.Count > 0)
{
lbx_subimageThumbnails.UnselectAll();
lbx_subimageThumbnails.SelectedItems.Clear();
}
lbx_subimageThumbnails.SelectedIndex = 0;
// reset the preview pane size
sld_previewSize.Value = 1.0;
}
推荐答案
您是否在ListBox中的项目上覆盖了Equals()和GetHashCode()?我可以通过以下方式复制它:
Have you overidden Equals() and GetHashCode() on the items in the ListBox? I can replicate this by:
- 在列表中选择一个项目.
- 更改项目的属性会导致其哈希码更改.
- 选择其他项目.
不会从SelectedItems中删除第一项，也无法按照您所描述的方式手动将其删除.即使SelectionMode为单个，情况也是如此，如果重新选择第一个项目，则会导致引发异常.
The first item is not removed from SelectedItems and cannot be removed manually the in way you describe. This is the case even when SelectionMode is single, and will result in an exception being thrown should you re-select the first item.
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