从组合框项中获取XML元素 [英] Getting XML element from a Combobox item

问题描述

我正在使用WPF，我可以使用WPF使用以下代码填充来自xml文件的元素的组合框

 < ComboBox Grid.Column =1Height =21Horizo​​ntalAlignment =LeftMargin =0,32,0,0Name =QueryChooserVerticalAlignment =TopWidth =189ItemsSource ={Binding}SelectionChanged =QueryChooser_SelectionChanged/> 
  

我的xaml.cs

  private void Window_Loaded（object sender，RoutedEventArgs e）
 {
 Queryslistload（）; 
} 
 
 private void Queryslistload（）
 {
 var xElem = XElement.Load（@Querys.xml）; 
 
 var querys =来自xElem.Descendants（QueryLay）中的查询
 orderby query.Element（QueryName）。value 
 select query.Element（QueryName） 。值; 
 QueryChooser.ItemsSource = querys; 
 
} 
  

这是我的xml文件本身

 <？xml version =1.0encoding =utf-8standalone =yes？> 
< Querys> 
< QueryLay> 
< QueryID> 
 1 
< / QueryID> 
< QueryName>检查Logspace< / QueryName> 
< Query> dbcc sqlperf（logspace）< / Query> 
< / QueryLay> 
< QueryLay> 
< QueryID> 
 2 
< / QueryID> 
< QueryName> Check Spaceused< / QueryName> 
< Query> sp_spaceused< / Query> 
< / QueryLay> 
 
< / Querys> 
  

所以现在如果用户从组合框中选择检查空间，我希望查询元素显示在文本框

如何实现？

UPDATED

  public class Query 
 {
 public int Id {get;组; } 
 public string Name {get;组; } 
 public string Value {get;组; 
} 
 private void QueryChooser_SelectionChanged（object sender，SelectionChangedEventArgs e）
 {
 var xElem = XElement.Load（@Querys.xml）; 
 var querys = xElem.Descendants（QueryLay）。选择（e => 
 new Query {
 Id = Convert.ToInt32（e.Element（QueryID）。 ，
 Name = e.Element（QueryName）Value，
 Value = e.Element（Query）。value 
}）。OrderBy（q => q.Name ）
 select query.Element（QueryName）。 
 
 listBox1.ItemsSource = querys; 
} 
  

解决方案

而不是绑定 ComboBox 直接从您的查询返回的 XElement ，您应该创建表示QueryName / Query组合的自己的类型，然后定义一个LINQ-to-XML查询，它将元素投射到这种类型的序列。

然后可以绑定 ComboBox SelectedItem 到数据上下文中的一个属性。

例如：

查询类型

  public class Query 
 { 
 public int Id {get;组; } 
 public string Name {get;组; } 
 public string Value {get;组; 
} 
  

数据上下文

  var xElem = XElement.Load（@Querys.xml）; 
 
 this.Queries = xElem.Descendants（QueryLay）。选择（e => 
 new Query 
 {
 Id = Convert.ToInt32（e。 Element（QueryID）。
 Name = e.Element（QueryName）。value，
 Value = e.Element（Query）。value 
}）。 OrderBy（q => q.Name）; 
 
 public查询SelectedQuery {get;组; } 
  

查看

SelectedItem ={Binding SelectedQuery}
DisplayMemberPath =Name
.. 。/>

this.SelectedQuery.Value 在您的数据然后，上下文将为您提供所选的查询值。

I am trying to get an XML element in a textbox from the users choosen combox element also from the same XML file.

I am using WPF, i am able to populate the combobox with the elements from the xml file using the following code

 <ComboBox  Grid.Column="1" Height="21"  HorizontalAlignment="Left" Margin="0,32,0,0" Name="QueryChooser" VerticalAlignment="Top" Width="189" ItemsSource="{Binding}" SelectionChanged="QueryChooser_SelectionChanged" />

My xaml.cs

 private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            Queryslistload();
        }

        private void Queryslistload()
        {
            var xElem = XElement.Load(@"Querys.xml");

            var querys = from query in xElem.Descendants("QueryLay")
                         orderby query.Element("QueryName").Value
                         select query.Element("QueryName").Value;
            QueryChooser.ItemsSource = querys;

        }

this is my xml file itself

<?xml version="1.0" encoding="utf-8"  standalone="yes" ?> 
<Querys>
    <QueryLay>
    <QueryID>
        1
    </QueryID>
    <QueryName>Check Logspace</QueryName>
    <Query>dbcc sqlperf(logspace)</Query>
    </QueryLay>
    <QueryLay>
    <QueryID>
        2
    </QueryID>
    <QueryName>Check Spaceused</QueryName>
    <Query>sp_spaceused</Query>
    </QueryLay>

    </Querys>

so now if the user selects the check logspace from combobox i want the query element to be displayed in the textbox

how do i achieve this?

UPDATED

public class Query
        {
            public int Id { get; set; }
            public string Name { get; set; }
            public string Value { get; set; }
        }
        private void QueryChooser_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            var xElem = XElement.Load(@"Querys.xml");
            var querys =  xElem.Descendants("QueryLay").Select( e => 
                new Query{
                         Id = Convert.ToInt32(e.Element("QueryID").Value),
       Name = e.Element("QueryName").Value,
       Value = e.Element("Query").Value
                         }).OrderBy(q=>q.Name)
                         select query.Element("QueryName").Value ;

            listBox1.ItemsSource = querys;
        }

解决方案

Rather than bind the ComboBox directly to the XElement's returned from your query, you should create your own type which represents a QueryName/Query combination, and then define a LINQ-to-XML query which projects the elements to a sequence of this type.

You can then bind the ComboBox SelectedItem to a property on your data context.

E.g:

Query Type

public class Query
{
   public int Id { get; set; }
   public string Name { get; set; }
   public string Value { get; set; }
}

Data Context

var xElem = XElement.Load(@"Querys.xml");

this.Queries = xElem.Descendants("QueryLay").Select(e =>
     new Query 
     {
       Id = Convert.ToInt32(e.Element("QueryID").Value),
       Name = e.Element("QueryName").Value,
       Value = e.Element("Query").Value
     }).OrderBy(q => q.Name);

public Query SelectedQuery { get; set; }

View

<ComboBox ItemsSource="{Binding Queries}" 
    SelectedItem="{Binding SelectedQuery}" 
    DisplayMemberPath="Name"
    ... />

this.SelectedQuery.Value in your data context will then give you the selected query value.

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