LINQ to SQL查询通过WCF返回值 [英] LINQ to SQL query return value via WCF

问题描述

我想使用以下方法返回值：

  public   string  GetAge（ string  myName）
 {
 DataClasses1DataContext data =  new  DataClasses1DataContext（）; 
  var  myAge = 来自   data.Users 其中 a.uName == myName 选择 a; 
  return  myAge.ToString（）; 
} 

但是文本块中返回的值是：SELECT [t0]。[Id]，[t0]。[uName]，[t0] .uAge ...

WP代码是：

  private   void  Button_Click（ object  sender，RoutedEventArgs e）
 {
 ServiceReference1.Service1Client proxy =  new  ServiceReference1.Service1Client（）; 
 proxy.GetAgeCompleted + = SetAgeText; 
  string  myName =   Nick; 
 proxy.GetAgeAsync（myName）; 
} 
 
  private   void  SetAgeText（ object  sender，ServiceReference1.GetAgeCompletedEventArgs e）
 {
 AgeTxtBlck.Text = e.Result; 
} 
 

请你更正此代码。

解决方案

在你的GetAge方法构建查询但忘记运行它。

所以你应该改变你的代码：

  public   string  GetAge（ string  myName）
 {
 DataClasses1DataContext data =  new  DataClasses1DataContext（）; 
  var  myAge = 来自   data.Users 其中 a.uName == myName 选择 a; 
用户user = myAge.FirstOrDefault（）;  //  运行查询!!!  
  return （user ==  null ？ null ：user.uAge.ToString（））;  //  将用户年龄作为字符串返回！ 
} 

I want to return the value using the following method:

public string GetAge(string myName)
        {
            DataClasses1DataContext data = new DataClasses1DataContext();
            var myAge = from a in data.Users where a.uName == myName select a;
            return myAge.ToString();
        }

But the returned value in the textblock is: "SELECT [t0].[Id], [t0].[uName], [t0].uAge..."
The WP code is:

private void Button_Click(object sender, RoutedEventArgs e)
       {
           ServiceReference1.Service1Client proxy = new ServiceReference1.Service1Client();
           proxy.GetAgeCompleted += SetAgeText;
           string myName = "Nick";
           proxy.GetAgeAsync(myName);
       }

       private void SetAgeText(object sender, ServiceReference1.GetAgeCompletedEventArgs e)
       {
           AgeTxtBlck.Text = e.Result;
       }

Could you correct this code please.

解决方案

In your GetAge method you build the query but forget to run it.
So you should change your code like this:

public string GetAge(string myName)
        {
            DataClasses1DataContext data = new DataClasses1DataContext();
            var myAge = from a in data.Users where a.uName == myName select a;
            User user = myAge.FirstOrDefault(); //Run the query!!!
            return (user == null ? null : user.uAge.ToString()); //Return the user age as string!
        }

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