数据绑定访问在xaml vs的代码背后 - Linq到XML？ [英] Data binding access in xaml vs in code behind - Linq to XML?

问题描述

我有一个列表框绑定到XML文件并显示Name元素。选择列表框项目时，我想在文本块中显示与该项目相关联的价格值。如何以编程方式检索价格（意味着不是在xaml文件中，而是在代码中）？谢谢。

XML文件具有以下节点：

 < Product> ; 
< Name> Book< / Name> 
< Price> 7< / Price> 
< / Product> 
  

我使用Linq并执行选择 匿名类型。如果以编程方式访问现场的最简单的方法是通过命名类型，请告诉我如何。

以下是我在xaml中绑定的方式（使用每个列表框项目的数据模板包含）：

 < TextBlock Text ={Binding Name}/> 
  

这是代码隐藏功能，我想检索价格：

  private void listBox1_SelectionChanged（object sender，SelectionChangedEventArgs e）
 {
 //如何获取所选项目的价格值这里？ 
} 
  

请注意，我想访问此功能的价格，在xaml！

解决方案

首先你可能不需要LINQ，因为你可以做很多包含 XmlDocuments 的内容包括通过XPath进行选择（

其次将匿名类型转换为命名类型是微不足道的，如果您有

p>

  select new {Name = ...，Price = ...} 
  

您只需要一个具有相应属性的课程

 选择新产品{Name = ...，Price = ...} 
  





  public class Product 
 {
 public string Name {get;组; } 
 public string Price {get;组; } //数据类型取决于你... 
} 
  

第三，你可以做没有命名类型，使用 动态 。

  private void listBox1_SelectionChanged（object sender，SelectionChangedEventArgs e）
 { 
 var listBox =（ListBox）sender; 
 //命名类型：
产品item =（Product）listBox.SelectedItem; 
 //匿名类型：
动态项= listBox.SelectedItem; 
 //<使用item.Price执行某些操作，可能需要在使用动态> 
 //例如MessageBox.Show（（string）item.Price）; 
} 
  




I have a listbox that binds to and displays the Name elements from an XML file. When a listbox item is selected, I want to display the Price value associated with this item in a textblock. How do I retrieve the Price programmatically (meaning not in the xaml file but in code behind)? Thanks.

XML file has these nodes:

<Product>
    <Name>Book</Name>
    <Price>7</Price>
</Product>

I use Linq and do the select with an anonymous type. If the easiest way to access the field programmatically is through a named type, please show me how.

Here's how I bind in xaml (using a data template for each listbox item that contains):

 <TextBlock Text = "{Binding Name}" />

Here's the code-behind function where I want to retrieve the Price:

        private void listBox1_SelectionChanged(object sender, SelectionChangedEventArgs e)
    { 
       // how do I get the value of Price of the selected item here?
    }

Please note that I want to access Price in this function, NOT in xaml!

解决方案

First of all you probably don't even need LINQ as you can do a lot of things with XmlDocuments including doing selection via XPath (also in Bindings).

Secondly converting anonymous types to named types is trivial, if you have

select new { Name = ..., Price = ... }

You just need a class with the respective properties

select new Product { Name = ..., Price = ... }

public class Product
{
     public string Name { get; set; }
     public string Price { get; set; } // Datatype is up to you...
}

Thirdly you can make do without named types using dynamic.

private void listBox1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{ 
   var listBox = (ListBox)sender;
   // Named type:
   Product item = (Product)listBox.SelectedItem;
   // Anonymous type:
   dynamic item = listBox.SelectedItem;
   // <Do something with item.Price, may need to cast it when using dynamic>
   // e.g. MessageBox.Show((string)item.Price);
}

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