列表视图更改所选项目的外观
本文关键字：项目 外观 选项 视图 列表 | 更新日期: 2024-09-24 11:44:42
我有以下ListView
<ListView VerticalAlignment="Top" HorizontalAlignment="Left" Width="175"
Height="200" Grid.Row="2" Name="StepsList" SelectionMode="Single"
ItemsSource="{Binding Steps}" Margin="0,5,0,0" Grid.RowSpan="2"
SelectionChanged="StepsList_SelectionChanged"
ScrollViewer.HorizontalScrollBarVisibility="Disabled">
<ListView.View>
<GridView>
<GridViewColumn Width="170" Header="Steps">
<GridViewColumn.CellTemplate>
<DataTemplate>
<Grid Width="165" GotFocus="StepsGrid_OnGotFocus"
LostFocus="StepsGrid_OnLostFocus">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="105"/>
<ColumnDefinition Width="15"/>
<ColumnDefinition Width="15"/>
</Grid.ColumnDefinitions>
<views:EditableTextBlock Grid.Column="0"
Text="{Binding Number}" HorizontalAlignment="Left"/>
<Button Name="StepUp" Grid.Column="1"
Content="↑" HorizontalAlignment="Right"/>
<Button Grid.Column="2" Content="↓" HorizontalAlignment="Right"/>
</Grid>
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
<GridView.ColumnHeaderContainerStyle>
<Style TargetType="{x:Type GridViewColumnHeader}">
<Setter Property="IsEnabled" Value="False"/>
</Style>
</GridView.ColumnHeaderContainerStyle>
</GridView>
</ListView.View>
</ListView>
我想要的是，Button只有在选择了项目时才可见，如果选择的项目是列表中最顶部/底部的项目，则要禁用向上/向下按钮。
我怎样才能做到这一点？
这里有一个使用MultiBinding的解决方案。你可能想调整逻辑，正如Blam所说，我不认为你真的想禁用两个界外点的两个按钮，但你就是这么说的…
XAML:
<Button Name="StepUp" Grid.Column="1" Content="↑" HorizontalAlignment="Right" >
<Button.Visibility>
<MultiBinding Converter="{StaticResource OuterboundsConverter}">
<Binding Path="DataContext.Steps" RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type Window}}"/>
<Binding></Binding>
</MultiBinding>
</Button.Visibility>
</Button>
<Button Grid.Column="2" Content="↓" HorizontalAlignment="Right">
<Button.Visibility>
<MultiBinding Converter="{StaticResource OuterboundsConverter}">
<Binding Path="DataContext.Steps" RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type Window}}"/>
<Binding></Binding>
</MultiBinding>
</Button.Visibility>
</Button>
转换器：
public class OuterboundsConverter : IMultiValueConverter
{
public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
Visibility vis = Visibility.Visible;
if (values != null)
{
ObservableCollection<string> steps = values[0] as ObservableCollection<string>;
string item = values[1] as string;
if (steps != null && item != null)
{
if (steps.Count > 0)
{
if (steps[0] == item || steps[steps.Count - 1] == item)
{
vis = Visibility.Collapsed;
}
}
}
}
return vis;
}
public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
{
throw new NotImplementedException();
}
}
我最终得到了以下内容
xml
<ListView VerticalAlignment="Top" HorizontalAlignment="Left" Width="175" Height="200" Grid.Row="2" Name="StepsList" SelectionMode="Single"
ItemsSource="{Binding Steps}"
Margin="0,5,0,0" Grid.RowSpan="2" SelectionChanged="StepsList_SelectionChanged">
<ListView.View>
<GridView>
<GridViewColumn Width="170" Header="Steps">
<GridViewColumn.CellTemplate>
<DataTemplate>
<Grid Width="165">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="105"/>
<ColumnDefinition Width="15"/>
<ColumnDefinition Width="15"/>
</Grid.ColumnDefinitions>
<views:EditableTextBlock Grid.Column="0" Text="{Binding Number}" HorizontalAlignment="Left"/>
<Button Name="StepUp" Grid.Column="1" Content="↑" HorizontalAlignment="Right" Visibility="Hidden" Click="StepUp_OnClick"/>
<Button Name="StepDown" Grid.Column="2" Content="↓" HorizontalAlignment="Right" Visibility="Hidden" Click="StepDown_OnClick"/>
</Grid>
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
<GridView.ColumnHeaderContainerStyle>
<Style TargetType="{x:Type GridViewColumnHeader}">
<Setter Property="IsEnabled" Value="False"/>
</Style>
</GridView.ColumnHeaderContainerStyle>
</GridView>
</ListView.View>
</ListView>
c#
private void StepsList_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
_viewModel.SetStep(StepsList.SelectedIndex);
var gridView = StepsList.View as GridView;
var listBoxItem = StepsList.ItemContainerGenerator.ContainerFromItem(StepsList.SelectedItem) as ListBoxItem;
var listBoxItems = Enumerable.Range(0, StepsList.Items.Count).Select(x => StepsList.ItemContainerGenerator.ContainerFromIndex(x) as ListBoxItem);
var column = gridView.Columns[0];
Button up;
Button down;
foreach (var contentPresenter in listBoxItems.Where(x => x != null).Select(x => x.GetVisualChild<ContentPresenter>()))
{
up = column.CellTemplate.FindName("StepUp", contentPresenter) as Button;
down = column.CellTemplate.FindName("StepDown", contentPresenter) as Button;
up.Visibility = Visibility.Hidden;
down.Visibility = Visibility.Hidden;
up.IsEnabled = true;
down.IsEnabled = true;
}
if (listBoxItem == null) return;
var myContentPresenter = listBoxItem.GetVisualChild<ContentPresenter>();
up = column.CellTemplate.FindName("StepUp", myContentPresenter) as Button;
down = column.CellTemplate.FindName("StepDown", myContentPresenter) as Button;
if (up == null) return;
up.Visibility = Visibility.Visible;
if (Equals(_viewModel.Steps.First(), StepsList.SelectedItem))
up.IsEnabled = false;
if (down == null) return;
down.Visibility = Visibility.Visible;
if (Equals(_viewModel.Steps.Last(), StepsList.SelectedItem))
down.IsEnabled = false;
}