Question

希望这对经验丰富的WPF用户来说是显而易见的。在绑定时，我必须考虑我绑定的目标的（嵌入）级别吗？

在下面的XAML中，我有MyTextBox，它可以接受我自己的额外validationRules列表，FileNameValidationRule有一个PathStr类型的ValidPathStr，它有一个InputPathStr字符串依赖属性。

为了测试我的理论，我尝试将MyTextBox的Text绑定到与MyTextBox的InputPathStr相同的绑定。 Text的绑定似乎有效（虽然不正确，但仍尝试解析绑定）但是对InputPathStr的绑定给出了“找不到框架导师”的错误。下面的跟踪显示了输出，第一个块是文本绑定，第二个块是失败的InputPathStr绑定。

我希望绑定既可以工作，也可以两者都失败，我应该如何改变InputPathStr的绑定，使其像Text一样工作？

感谢。

        <my2:MyTextBox x:Name="m_renameTextBox" 
                            Text="{Binding Path=SourceBrowseDir.ItemFullPath, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}" >
        <my2:MyTextBox.AdditionalValidationRules>
            <src:FileNameValidationRule>
                <src:FileNameValidationRule.ValidPathStr>
                    <src:PathStr InputPathStr="{Binding Path=SourceBrowseDir.ItemFullPath, Mode=OneWay, UpdateSourceTrigger=PropertyChanged}"/>
                </src:FileNameValidationRule.ValidPathStr>
            </src:FileNameValidationRule>
        </my2:MyTextBox.AdditionalValidationRules>
    </my2:MyTextBox >

输出是：

> Created BindingExpression (hash=3780752) for Binding (hash=63892678)
  Path: 'SourceBrowseDir.ItemFullPath'
BindingExpression (hash=3780752): Attach to ScreenControls.HelperUserControls.MyTextBox.Text (hash=20793123)
BindingExpression (hash=3780752): Resolving source 
BindingExpression (hash=3780752): Found data context element: MyTextBox (hash=20793123) (OK)
BindingExpression (hash=3780752): Activate with root item PresetsNavigatorViewModel (hash=34365244)
BindingExpression (hash=3780752):   At level 0 using cached accessor for PresetsNavigatorViewModel.SourceBrowseDir: RuntimePropertyInfo(SourceBrowseDir)
BindingExpression (hash=3780752): Replace item at level 0 with PresetsNavigatorViewModel (hash=34365244), using accessor RuntimePropertyInfo(SourceBrowseDir)
BindingExpression (hash=3780752): GetValue at level 0 from PresetsNavigatorViewModel (hash=34365244) using RuntimePropertyInfo(SourceBrowseDir): <null>
BindingExpression (hash=3780752):   Item at level 1 is null - no accessor
BindingExpression (hash=3780752): TransferValue - got raw value {DependencyProperty.UnsetValue}
BindingExpression (hash=3780752): TransferValue - using fallback/default value ''
BindingExpression (hash=3780752): TransferValue - using final value ''
> 
> Created BindingExpression (hash=56631954) for Binding (hash=47211710)
  Path: 'SourceBrowseDir.ItemFullPath'
BindingExpression (hash=56631954): Attach to ScreenControls.Helper.PathStr.InputPathStr (hash=40208759)
BindingExpression (hash=56631954): Use Framework mentor <null>
BindingExpression (hash=56631954): Resolving source 
BindingExpression (hash=56631954): Framework mentor not found
BindingExpression (hash=56631954): Resolve source deferred

Answer 1

找到解决方案here。这是由于DataContext没有被遗传，显然。

WPF在不同级别绑定

1 个答案: