WPF绑定错误

时间 2019-11-16

标签 wpf 绑定错误繁體版

原文原文链接

listbox绑定遇到了奇怪的报错以下：spa

System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.ItemsControl', AncestorLevel='1''. BindingExpression:Path=Background; DataItem=null; target element is 'ListBoxItem' (Name=''); target property is 'Background' (type 'Brush')
System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.ItemsControl', AncestorLevel='1''. BindingExpression:Path=HorizontalContentAlignment; DataItem=null; target element is 'ListBoxItem' (Name=''); target property is 'HorizontalContentAlignment' (type 'HorizontalAlignment')
System.Windows.Data Error: 4 : Cannot find source for binding with reference 'RelativeSource FindAncestor, AncestorType='System.Windows.Controls.ItemsControl', AncestorLevel='1''. BindingExpression:Path=VerticalContentAlignment; DataItem=null; target element is 'ListBoxItem' (Name=''); target property is 'VerticalContentAlignment' (type 'VerticalAlignment')

分析下，我listboxitem根本就没有设置这些啊，通过不断摸索发现，应该是默认的样式，wpf的listboxitem默认样式以下：code

Style
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:s="clr-namespace:System;assembly=mscorlib"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    TargetType="{x:Type ListBoxItem}">
    <Style.Resources>
       <ResourceDictionary/>
    </Style.Resources>
    <Setter Property="Panel.Background">
       <Setter.Value>
          <SolidColorBrush>
        #00FFFFFF
          </SolidColorBrush>
       </Setter.Value>
    </Setter>
    <Setter Property="Control.HorizontalContentAlignment">
       <Setter.Value>
          <Binding Path="HorizontalContentAlignment" RelativeSource="{RelativeSource Mode=FindAncestor, AncestorType=ItemsControl, AncestorLevel=1}"/>
       </Setter.Value>
    </Setter>
    <Setter Property="Control.VerticalContentAlignment">
       <Setter.Value>
          <Binding Path="VerticalContentAlignment" RelativeSource="{RelativeSource Mode=FindAncestor, AncestorType=ItemsControl, AncestorLevel=1}"/>
       </Setter.Value>
    </Setter>
    <Setter Property="Control.Padding">
       <Setter.Value>
          <Thickness>
        2,0,0,0
          </Thickness>
       </Setter.Value>
    </Setter>
    <Setter Property="Control.Template">
       <Setter.Value>
          <ControlTemplate TargetType="{x:Type ListBoxItem}">
             ...
          </ControlTemplate>
       </Setter.Value>
    </Setter>
 </Style>

尝试以下覆盖原来的样式方法解决，发现仍是同样报错xml

 <Style TargetType="ListBoxItem">
                                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                                        <Setter Property="VerticalContentAlignment" Value="Center" />
                                    </Style>

，最终发现要这样解决才能够blog

<ListBox.Resources>
                                    <Style TargetType="ListBoxItem">
                                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                                        <Setter Property="VerticalContentAlignment" Value="Center" />
                                    </Style>
                                </ListBox.Resources>
                                <ListBox.ItemContainerStyle>
                                    <Style TargetType="ListBoxItem">
                                        <Setter Property="HorizontalContentAlignment" Value="Center" />
                                        <Setter Property="VerticalContentAlignment" Value="Center" />
                                    </Style>
                                </ListBox.ItemContainerStyle>