我如何重用以下触发器？我需要将其重用于窗口中的所有清除按钮。按钮仅在列表视图中选择项目时可见。所以我需要传递Binding ElementName=teachers作为参数。有没有办法做到这一点？
<Button Width="15" Grid.Column="1" Content="X" Margin="0,2,5,2" Command="{Binding ClearSubjectCommand}" HorizontalAlignment="Center" HorizontalContentAlignment="Center" VerticalContentAlignment="Center">
<Button.Style>
<Style TargetType="{x:Type Button}">
<Setter Property="Visibility" Value="Visible"></Setter>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=teachers, Path=SelectedItem}" Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
修改 的
尝试附属物。但没有成功。
<Button Width="15" Grid.Column="1" Content="X" Margin="0,2,5,2" Command="{Binding ClearSubjectCommand}"
HorizontalAlignment="Center" HorizontalContentAlignment="Center" VerticalContentAlignment="Center"
local:ThemeProperties.BindingElementName="teachers" Style="{StaticResource cancelButton}"/>
和风格，
<Style TargetType="{x:Type Button}" x:Key="cancelButton">
<Setter Property="Visibility" Value="Visible"></Setter>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName= local:ThemeProperties.BindingElementName, Path=SelectedItem}" Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
类，
public static class ThemeProperties
{
public static string GetBindingElementName(DependencyObject obj)
{
return (string)obj.GetValue(BindingElementNameProperty);
}
public static void SetBindingElementName(DependencyObject obj, string value)
{
obj.SetValue(BindingElementNameProperty, value);
}
// Using a DependencyProperty as the backing store for BindingElementName. This enables animation, styling, binding, etc...
public static readonly DependencyProperty BindingElementNameProperty =
DependencyProperty.RegisterAttached("BindingElementName", typeof(string), typeof(ThemeProperties), new FrameworkPropertyMetadata("teachers"));
}
答案 0 :(得分：1)
如何将样式声明为Resource并使用StaticResource标记扩展名重新使用它 -
<Window.Resources>
<Style>
<Style x:Key="CommonButtonStyle" TargetType="{x:Type Button}">
<Setter Property="Visibility" Value="Visible"></Setter>
<Style.Triggers>
<DataTrigger Binding="{Binding ElementName=teachers,
Path=SelectedItem}"
Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed"></Setter>
</DataTrigger>
</Style.Triggers>
</Style>
</Style>
</Window.Resources>
并将其用于不同的按钮 -
<Button x:Name="Button1" Style="{StaticResource CommonButtonStyle}"/>
<Button x:Name="Button2" Style="{StaticResource CommonButtonStyle}"/>
<Button x:Name="Button3" Style="{StaticResource CommonButtonStyle}"/>
<强>更新
如果ListView位于Button的可视树中的某个位置，您可以在样式中使用RelativeSource，而不是使用ElementName绑定此类内容 -
<DataTrigger Binding="{Binding Path=SelectedItem, RelativeSource={RelativeSource
FindAncestor, AncestorType=ListView}}"
Value="{x:Null}">
但是如果它们不相关，则需要使用attached property将参数传递给样式。此链接here可能会帮助您入门。
更新2
我已经使用附加属性但修改了代码的位。这是 -
public static class ThemeProperties
{
public static object GetSelectedValue(DependencyObject obj)
{
return (object)obj.GetValue(SelectedValueProperty);
}
public static void SetSelectedValue(DependencyObject obj, object value)
{
obj.SetValue(SelectedValueProperty, value);
}
public static readonly DependencyProperty SelectedValueProperty =
DependencyProperty.RegisterAttached("SelectedValue", typeof(object),
typeof(ThemeProperties), new FrameworkPropertyMetadata(null,
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
}
XAML -
<Style TargetType="{x:Type Button}" x:Key="cancelButton">
<Setter Property="Visibility" Value="Visible"/>
<Style.Triggers>
<Trigger Property="local:ThemeProperties.SelectedValue"
Value="{x:Null}">
<Setter Property="Visibility" Value="Collapsed"></Setter>
</Trigger>
</Style.Triggers>
</Style>
这是ListView和按钮 -
<StackPanel>
<ListView x:Name="lstView" ItemsSource="{Binding Objects}">
<ListView.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Name}"/>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<Button VerticalAlignment="Bottom" Height="30" Width="100"
local:ThemeProperties.SelectedValue="{Binding SelectedItem,
ElementName=lstView}"
Style="{StaticResource cancelButton}"/>
</StackPanel>
答案 1 :(得分：0)
我真的很抱歉我花了这么久。但最后我明白了。我使用自定义转换器，我知道它不是你想要的，但它工作得很好。它提供了您想要的功能。
首先，我的 SelectionToVisibilityConverter
public class SelectionToVisibilityConverter : IValueConverter
{
public object Convert(
object value,
Type targetType,
object parameter,
CultureInfo culture)
{
if (value == null)
{
return Visibility.Collapsed;
}
return Visibility.Visible;
}
public object ConvertBack(
object value,
Type targetType,
object parameter,
CultureInfo culture)
{
throw new NotImplementedException();
}
}
以下是我的观点：
<UserControl.Resources>
<Test:SelectionToVisibilityConverter x:Key="VisibilityConverter" />
</UserControl.Resources>
<Grid>
<ListView Height="100" HorizontalAlignment="Left" Margin="29,29,0,0" Name="listView1" ItemsSource="{Binding Path=TestItems}" SelectedItem="{Binding Path=TestItemsSelectedItem}" VerticalAlignment="Top" Width="120" />
<ListView Height="100" HorizontalAlignment="Left" Margin="155,29,0,0" Name="listView2" ItemsSource="{Binding Path=TestItems2}" SelectedItem="{Binding Path=TestItems2SelectedItem}" VerticalAlignment="Top" Width="120" />
<Button Content="Button" Command="{Binding Path=ReloadCommand}" Visibility="{Binding ElementName=listView1, Path=SelectedItem, Converter={StaticResource VisibilityConverter}}" Height="23" HorizontalAlignment="Left" Margin="29,135,0,0" Name="button1" VerticalAlignment="Top" Width="75" />
<Button Content="Button" Command="{Binding Path=ReloadCommand}" Visibility="{Binding ElementName=listView2, Path=SelectedItem, Converter={StaticResource VisibilityConverter}}" Height="23" HorizontalAlignment="Left" Margin="155,135,0,0" Name="button2" VerticalAlignment="Top" Width="75" />
</Grid>
请忽略ListViews上的SelectedItem和按钮上的ReloadCommand。我用它来测试这个。每次选择某个ListView的项目时，都会重新评估相应按钮的可见性。
修改
我的最后一个想法是创建自定义控件并为此控件定义样式/模板。像这样：
<Style x:Key="CustomControlStyle" TargetType="{x:Type Test:MyFirstCustomControl}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Test:MyFirstCustomControl}">
<Grid>
<ListView Height="100" HorizontalAlignment="Left" Margin="5, 5, 0, 0" Name="listView1" VerticalAlignment="Top" Width="120" />
<Button Content="Button" Height="23" HorizontalAlignment="Left" Margin="50,110,0,0" Name="button1" VerticalAlignment="Top" Width="75" />
</Grid>
<ControlTemplate.Triggers>
<DataTrigger Binding="{Binding ElementName=listView, Path=SelectedItem}" Value="{x:Null}">
<Setter Property="Visibility" TargetName="button1" Value="Collapsed"></Setter>
</DataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
这样，触发器将在您设置
的所有MyFirstConstomControl之间共享Style="{StaticResource CustomControlStyle}"
我认为这不容易，但我不知道更好，所以我只是把我得到的东西带来。