La requête Linq renvoie true ou false

J'ai une requête où il doit retourner TRUE ou 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

et je veux joindre ce résultat de la requête à une propriété de type de données chaîne)

this.result = Conert.ToBoolean(query);

comment réaliser cela dans LINQ ?

EDIT:

EmpMapper classe

  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 classe

      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;
     }
     }

source d'informationauteur user1221765

  1. 21

    essayer cela,

     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
  2. 4

    Si je vous comprends bien, vous voulez obtenir true si l'un des résultats de la requête correspond à toutes les conditions. Dans ce cas, essayez quelque chose comme ceci:

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

this.result = found.ToString();
  3. 3

    Vous pouvez utiliser .() Ou .Count(). () Est mieux. (Cochez cette DONC, la question de voir pourquoi)

    .()

    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 = query.Any().ToString()

    .Count()

    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 = (query.Count() > 0).ToString()
  4. 0
    var query = from c in db.Emp
            from d in db.EmpDetails 
            select new { c.ID == y.ID &&  
                         c.FirstName == "A" && 
                         c.LastName == "D" };
  5. 0

    Si vous voulez vraiment avoir un "vrai" ou "faux" Chaîne de Réponse:

        public string result
    {
        get
        {
            return db.Emp.SelectMany(c => db.EmpDetails, (c, d) => new {c, d})
                         .Where(@t => c.ID == y.ID && c.FirstName == "A" && c.LastName == "D")
                         .Select(@t => c)).Any().ToString();
        }
    }

    Mais je vous propose de faire de la propriété "résultat" d'une valeur bool et retirer le ToString().
    Une fois que vous avez une valeur booléenne que vous pouvez toujours faire un ToString() sur celui-ci