LINQ查询返回TRUE或FALSE [英] Linq query return true or false

问题描述

我有一个查询，它应该返回TRUE或FALSE。

  VAR的查询=从C在db.Emp 
从db.EmpDetails 
 D，其中c。 ID == d.ID和放大器;&安培; c.FirstName ==A和放大器;&安培; c.LastName ==D
 //它应该在这个上面的说法符合所有这些条件
  

$ B返回TRUE $ b

和我想这个查询结果附加到一个属性（字符串数据类型）

  this.result = Conert .ToBoolean（查询）; 
  

如何在LINQ实现这一目标？

编辑：

EmpMapper类

 公共类EmpMapper 
 {
 EmpEntities分贝; 
 // ID列已存在于数据库
私人诠释身份证; 
 //我创建这个属性将其从UI侧增加，这取决于在查询中的某些条件。这就是为什么我创建了一个单独的类来映射从DB 
布尔结果现有的ID; 
公共EmpMapper（INT ID，布尔结果）
 {
 this.db =新EmpEntites（）; 
 this.ID = ID; 
 VAR的查询=从C与D在db.EmpDetails 
 db.Emp 
，其中c.ID == d.ID&放大器;&安培; c.FirstName ==A和放大器;&安培; c.LastName ==D
 //它应该在这个上面的说法符合所有这些条件
 this.result = Convert.ToBoolean（查询）返回TRUE; 
} 
公众诠释ID 
 {
 {返回this.ID;} 
集合{this.ID =值;} 
} 
酒店的公共布尔结果
 {
 {返回this.result;} 
集合{this.result =值;} 
} 
} 
  

MainViewModel类

 名单，LT ; EmpMapper> empMapCol =新的List< EmpMapper>（）; 
 
私人无效PAGE_LOADED（对象发件人，RoutedEventArgs E）
 {
 VAR emp_query =从C在db.Emp 
排序依据c.ID 
选择; 
名单，LT;&的Emp GT; empCol = emp_query.ToList（）; 
的foreach（在empCol的Emp项）
 {
 this.empMapCol.Add（新EmpMapper（item.ID，item.result））; 
} 
 datagrid1.ItemsSource = empMapCol; 
} 
} 
  

解决方案

尝试对此，

  VAR的查询=（从C与D在db.EmpDetails 
 db.Emp 
其中，c.ID == d.ID&放大器;&安培; c.FirstName ==A和放大器;&安培; c.LastName ==D
选择C 
）。任何（）; 
 
 this.result =查询; //无需转换为boolean其已经布尔值
  

I have a query where it should return TRUE or FALSE.

var query = from c in db.Emp
            from d in db.EmpDetails 
            where c.ID == d.ID && c.FirstName == "A" && c.LastName == "D" 
          // It should return TRUE when this above statement matches all these conditions

and I want to attach this query result to a property(of string datatype)

this.result = Conert.ToBoolean(query);

how to achieve this in LINQ ?

EDIT:

EmpMapper class

  public class EmpMapper
  {
    EmpEntities db;
    // ID column already exists in the DB
    private int ID;
    // I am creating this property to add it from the UI side, depending on the certain conditions in the query. That is why I created a separate class to map the existing ID from the DB
    bool result;
    public EmpMapper(int ID, bool result)
    {
      this.db = new EmpEntites();
      this.ID = ID;
      var query = from c in db.Emp
            from d in db.EmpDetails 
            where c.ID == d.ID && c.FirstName == "A" && c.LastName == "D" 
          // It should return TRUE when this above statement matches all these conditions
      this.result = Convert.ToBoolean(query);
    }
   public int ID
   {
    get{return this.ID;}
    set{this.ID = value;}
   }
   public bool result
   {
    get{return this.result;}
    set{this.result = value;}
   }
   } 

MainViewModel class

      List<EmpMapper> empMapCol = new List<EmpMapper>();

     private void Page_Loaded(object sender, RoutedEventArgs e)
    {
      var emp_query = from c in db.Emp
                      orderby c.ID
                      select a;
     List<Emp> empCol = emp_query.ToList();
     foreach(Emp item in empCol)
     {
       this.empMapCol.Add(new EmpMapper(item.ID, item.result)); 
     }
     datagrid1.ItemsSource = empMapCol;
     }
     }

解决方案

try this,

 var query = (from c in db.Emp
        from d in db.EmpDetails 
        where c.ID == d.ID && c.FirstName == "A" && c.LastName == "D"
         select c 
         ).Any(); 

  this.result = query; //no need to convert to boolean its already bool value

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