WPF 2 ComboBox绑定问题
我有以下问题：
有一个类有几个字符串属性
有这样的类实体的集合，
该集合显示在某些窗口左侧的树中，详细信息显示在右侧。 我详细地将所选节点的字符串属性绑定到组合框。
第一个组合框始终具有相同的 ItemsSource，但第二个 ItemsSource 取决于第一个组合的 SelectedItem...
<ComboBox
Grid.Column="1"
SelectedIndex="0"
x:Name="cbClass"
Style="{DynamicResource ComboBoxValidationError}"
SelectedValue="{Binding Path=Description.Node.ClassName, ElementName=userControl, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
ItemsSource="{Binding Source={StaticResource classesProvider}}"
Width="Auto"
Height="Auto"
DisplayMemberPath="Description"
SelectedValuePath="FQN" />
<ComboBox
Grid.Column="1"
SelectedIndex="0"
Grid.Row="1"
x:Name="cbMethod"
SelectedValue="{Binding Path=Description.Node.MethodName, ElementName=userControl, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged,diag:PresentationTraceSources.TraceLevel=High}"
ItemsSource="{Binding Path=SelectedItem.Methods, ElementName=cbClass, Mode=Default,diag:PresentationTraceSources.TraceLevel=High}"
Style="{DynamicResource ComboBoxValidationError}"
Width="Auto"
Height="Auto"
SelectedValuePath="Name"
DisplayMemberPath="Description" />
现在，当我在树中创建新节点时，两个字符串属性都具有 null 引用。 当第一个组合更改其新节点的 SelectedItem 时，第二个 ComboBox 将 null 绑定到旧节点的字符串值，该值是在树中创建新节点之前选择的......我想知道在这种情况下我应该做什么？
I have the following problem:
there is a class with a couple of string properties
there is a collection of such class entities
That collection is shown in tree on the left of some windows and details shown on the right. I'm binding string properties of selected node to comboboxes in details.
First combobox always have the same ItemsSource but the second one ItemsSource depends on SelectedItem of the first combo...
<ComboBox
Grid.Column="1"
SelectedIndex="0"
x:Name="cbClass"
Style="{DynamicResource ComboBoxValidationError}"
SelectedValue="{Binding Path=Description.Node.ClassName, ElementName=userControl, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
ItemsSource="{Binding Source={StaticResource classesProvider}}"
Width="Auto"
Height="Auto"
DisplayMemberPath="Description"
SelectedValuePath="FQN" />
<ComboBox
Grid.Column="1"
SelectedIndex="0"
Grid.Row="1"
x:Name="cbMethod"
SelectedValue="{Binding Path=Description.Node.MethodName, ElementName=userControl, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged,diag:PresentationTraceSources.TraceLevel=High}"
ItemsSource="{Binding Path=SelectedItem.Methods, ElementName=cbClass, Mode=Default,diag:PresentationTraceSources.TraceLevel=High}"
Style="{DynamicResource ComboBoxValidationError}"
Width="Auto"
Height="Auto"
SelectedValuePath="Name"
DisplayMemberPath="Description" />
Now when i create new node in the tree, both string properties have null reference. And when first combo changes its SelectedItem for the NEW node, second ComboBox binds null to the string value of the OLD node, which were selected before creating new node in the tree... I wonder what should i do in this case?
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我刚刚找到了答案。
绑定按照声明的顺序进行通知，WPF 不会分析绑定的依赖关系:)
因此，交换 ComboBox 的声明可以解决问题...在这种情况下这是可以接受的，因为我将这些 ComboBox 放入 Grid 中手动设置其 Grid.Row 和 Grid.Column...
虽然解决方案不太令人满意，但它有效！
I've just found an answer.
Binding are notified in the order of their declaration, WPF is not going to analyse dependencies of bindings :)
So swapping declarations of ComboBoxes solves the problem... It's acceptable in this scenario because I place these ComboBoxes in Grid manually setting their Grid.Row and Grid.Column...
Though solution is not very pleasing, it works!