WPF，XML数据绑定到依赖/级联组合框 [英] WPF, XML databinding into dependent/cascading ComboBoxes

问题描述

我有以下结构的XML文件：

 <产品> 
<产品名称=MyProduct1> 
<成分> 
<成分名称=MyComponent1> 
<&子GT; 
<子名=MySubComponent1/> 
<子名=MySubComponent2/> $ B $ ...更多子节点... 
< /子> 
< /成分> $ B $ ...更多组件节点... 
< /成分> 
< /产品与GT; $ B $ ...更多产品节点... 
< /产品> 
  

我试图创建一个与它的产品名称组合框一个WPF应用程序。我完全新的WPF，所以我不知道我要去的事情以正确的方式。当选择一个产品，一个第二组合框应与所有组件为该产品来填充。并且选择一个组件时，第三组合框应与所有的子组件，该组件填充。

我不知道如何设置组合框之间的相关性，除了填充由独立的组合框触发事件处理中的相关组合框。这似乎意味着，我需要能够读取C＃中的XML，所以我的 [Serializable接口] 类产品，产品，组件和子。不过，我试图做的XML数据绑定在我的XAML：

 < Window.Resources> 
< XmlDataProvider源=Products.xml
的XPath =产品/产品
 X：键=productsXml/> 
< /Window.Resources> 
  

我目前没有看到产品名称的列表，在我的第一个组合框，它的XAML是以下

 <组合框高度=23的Horizo​​ntalAlignment =左保证金=138,116,0,0
产品名称=cbo_productVerticalAlignment =评出的WIDTH =120
的ItemsSource ={绑定源= productsXml，XPath的= @名}
的SelectionChanged =product_SelectionChanged/> 
  

产品XML应该只读 - 用户将无法更改任何值从应用程序的XML。我只是想读取XML数据，并在应用中展示它

我有几个问题：

1. 我要对这个正确？有从我的WPF应用程序读取，有一个单独的XML文件 [Serializable接口] 代表在C＃中提取这些节点数据的目的XML文件中的节点，使用类事件处理程序组合框之间的代码的依赖等。


2. 为什么我的产品名称，例如，MyProduct1，在我的组合框显示？目前，它只是表明了空。


3. 看来几乎就像 [Serializable接口] 类代表我的XML节点是多余的/不必要的，因为XAML已经拥有了 XmlDataProvider / XPath的东西。 ？这样的话

编辑：

更新我的组合框的XAML以下，现在我看到我的产品名称列表在ComboBox，感谢的 decyclone的回答：

 <组合框高度=23的Horizo​​ntalAlignment =左保证金=138,116,0,0
 NAME =cbo_productVerticalAlignment =评出的WIDTH =120
的ItemsSource ={绑定源= {StaticResource的productsXml}}
的DisplayMemberPath =@名
的SelectionChanged =product_SelectionChanged/> 
  

解决方案

好吧，因为我找到了答案，我的<一个HREF =htt​​p://stackoverflow.com/questions/3389333/wpf-using-xpath-in-xaml-with-xmldataprovider-to-select-nodes-based-on-selected-v/>更具体的问题，我想我知道这个问题的答案了。我不需要在不同的节点 [Serializable接口] 班在我的XML，因为我可以只使用XAML和XPath创建级联/取决于组合框：

 <！ - 独立 - > 
<组合框高度=23的Horizo​​ntalAlignment =左保证金=138,116,0,0
 NAME =cbo_productVerticalAlignment =评出的WIDTH =120
的ItemsSource ={绑定源= {StaticResource的productsXml}}
的DisplayMemberPath =@名/> 
 
<！ - 依赖 - > 
<组合框高度=23的Horizo​​ntalAlignment =左保证金=138,151,0,0
 NAME =cbo_componentVerticalAlignment =评出的WIDTH =201
的DataContext ={绑定的ElementName = cbo_product，路径=的SelectedItem}
的ItemsSource ={绑定的XPath =组件/组件}
的DisplayMemberPath =@名/> 
  

I have an XML file with the following structure:

<Products>
  <Product name="MyProduct1">
    <Components>
      <Component name="MyComponent1">
        <SubComponents>
          <SubComponent name="MySubComponent1"/>
          <SubComponent name="MySubComponent2"/>
          ...more SubComponent nodes...
        </SubComponents>
      </Component>
      ...more Component nodes...
    </Components>
  </Product>
  ...more Product nodes...
</Products>

I'm trying to create a WPF app that has a ComboBox with the Product names in it. I am completely new to WPF so I don't know if I'm going about things the right way. When a Product is chosen, a second ComboBox should be populated with all the Components for that Product. And when a Component is chosen, a third ComboBox should be populated with all the SubComponents for that Component.

I don't know how to set up a dependency between ComboBoxes except to populate the dependent ComboBox inside an event handler triggered by the independent ComboBox. This seems to imply I need to be able to read the XML in C#, so I have [Serializable] classes for Products, Product, Component, and SubComponent. However, I was trying to do XML databinding in my XAML:

<Window.Resources>
    <XmlDataProvider Source="Products.xml"
                     XPath="Products/Product"
                     x:Key="productsXml"/>
</Window.Resources>

I'm currently not seeing a list of Product names in my first ComboBox, whose XAML is the following:

<ComboBox Height="23" HorizontalAlignment="Left" Margin="138,116,0,0"
          Name="cbo_product" VerticalAlignment="Top" Width="120"
          ItemsSource="{Binding Source=productsXml, XPath=@name}"
          SelectionChanged="product_SelectionChanged"/>

The Products XML should be read-only--the user won't be able to change any values in the XML from the app. I just want to read the XML data and display it in the app.

I have a few questions:

1. Am I going about this correctly? Having a standalone XML file from which my WPF app reads, having [Serializable] classes representing the nodes in the XML file for the purpose of extracting data from those nodes in C#, using an event handler to code dependencies between ComboBoxes, etc.
2. Why don't my product names, e.g., MyProduct1, show up in my ComboBox? Currently it just shows up empty.
3. It seems almost like having [Serializable] classes for representing my XML nodes is redundant/unnecessary since XAML already has the XmlDataProvider/XPath stuff. Is this the case?

Edit:

Updated my ComboBox XAML to the following and now I see my list of Product names in the ComboBox, thanks to decyclone's answer:

<ComboBox Height="23" HorizontalAlignment="Left" Margin="138,116,0,0"
          Name="cbo_product" VerticalAlignment="Top" Width="120"
          ItemsSource="{Binding Source={StaticResource productsXml}}"
          DisplayMemberPath="@name"
          SelectionChanged="product_SelectionChanged"/>

解决方案

Okay, since I found an answer to my more specific question, I think I know the answer to this question, too. I don't need [Serializable] classes for the different nodes in my XML, because I can just use XAML and XPath to create cascading/dependent ComboBoxes:

<!-- Independent -->
<ComboBox Height="23" HorizontalAlignment="Left" Margin="138,116,0,0"
          Name="cbo_product" VerticalAlignment="Top" Width="120"
          ItemsSource="{Binding Source={StaticResource productsXml}}"
          DisplayMemberPath="@name"/>

<!-- Dependent -->
<ComboBox Height="23" HorizontalAlignment="Left" Margin="138,151,0,0"
          Name="cbo_component" VerticalAlignment="Top" Width="201"
          DataContext="{Binding ElementName=cbo_product, Path=SelectedItem}"
          ItemsSource="{Binding XPath=Components/Component}"
          DisplayMemberPath="@name"/>

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