我工作在一个大的WPF项目并调试我的输出窗口期间充满了这些恼人的警告：

I am working on a large WPF project and during debug my output window is filled with these annoying warnings:

System.Windows.Data信息：10：使用绑定和没有有效>回落值存在无法检索值;使用默认值代替。    BindingEx pression：路径= Horizo​​ntalContentAlignment; DataItem的= NULL; 目标元素是    ComboBoxItem （名称=''）; target属性是'Horizo​​ntalContentAlignment（类型>   的Horizo​​ntalAlignment'）

System.Windows.Data Information: 10 : Cannot retrieve value using the binding and no valid > fallback value exists; using default instead. BindingExpression:Path=HorizontalContentAlignment; DataItem=null; target element is 'ComboBoxItem' (Name=''); target property is 'HorizontalContentAlignment' (type >' HorizontalAlignment')

在该特定实例ComboBoxItem的样式是这样的：

In the specific example ComboBoxItem is styled in this way:

<Style x:Key="{x:Type ComboBoxItem}" TargetType="{x:Type ComboBoxItem}">
    <Setter Property="OverridesDefaultStyle" Value="True"/>
    <Setter Property="SnapsToDevicePixels" Value="True"/>                  
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ComboBoxItem}">
                <Border 
                    Name="bd"
                    Padding="4,4,4,4"
                    SnapsToDevicePixels="True" 
                    CornerRadius="2,2,2,2">
                    <ContentPresenter />
                </Border>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsHighlighted" Value="true">
                        <Setter TargetName="bd" Property="Background"  Value="{StaticResource MediumBrush}"/>
                        <Setter TargetName="bd" Property="Padding"  Value="4,4,4,4"/>
                        <Setter TargetName="bd" Property="CornerRadius"  Value="2,2,2,2"/>
                    </Trigger>
                </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

我知道这是默认主题定义所产生的问题的 ComboBoxItem ，它包含的东西，如：

I know that the problem is generated by the default theme definition for ComboBoxItem that contains things like:

<Setter Property="Control.HorizontalContentAlignment">
        <Setter.Value>
            <Binding Path="HorizontalContentAlignment" RelativeSource="{RelativeSource Mode=FindAncestor, AncestorType=ItemsControl, AncestorLevel=1}" />
            </Setter.Value>
        </Setter>

但我也想到用

but I also thought that using

<Setter Property="OverridesDefaultStyle" Value="True"/> 

将采取照顾的问题，而是警告仍然存在。

would taken care of the problem, and instead warnings are still there.

编辑：为了再现您还需要重写组合框的风格在这个例子中，从MSDN酷似完成的问题： 组合框控件模板实例

In order to reproduce the problem you need to override also the style of ComboBox exactly like done in this example from MSDN: ComboBox ControlTemplate Example

任何帮助，真是AP preciated

Any help is really appreciated

推荐答案

这为我工作。把这个在您的Application.xaml文件。

This worked for me. Put this in your Application.xaml file.

<Application.Resources>
    <Style TargetType="ComboBoxItem">
        <Setter Property="HorizontalContentAlignment" Value="Left" />
        <Setter Property="VerticalContentAlignment" Value="Center" />
    </Style>
</Application.Resources>

这是...

http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/42cd1554-de7a-473b-b977-ddbd6298b3d0