LINQ选择只选择1，即使有更多的项目

Question

我有了要检查的客户端连接一个LINQ报表项目，其用户

 public List<Client_Dto> GetClientByBehandelaar(string loggedInUserId) 
    { 
     try 
     { 
      int userID = Convert.ToInt32(loggedInUserId); 
      nestorDBDataContext db = new nestorDBDataContext(); 
      var result = 
       (from relaties in db.tbl_Relaties 
       where relaties.ID_Persoon == userID 
       select new Client_Dto() 
       { 
        ID = relaties.NestorNrCliënt 
       }).ToList(); 
      List<Client_Dto> clienten = result; 
      return clienten; 
     } 
     catch (Exception e) 
     { 
      throw new ArgumentException("GetClientByBehandelaar Failed " + e); 
     } 
    } 

，但只选择一个，即使有87多个在具有相同用户标识的数据库。我一直盯着自己死在这一个..谁能帮

Answer 1

我在这里尝试过了，你的代码工作：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 

namespace ConsoleApplication1 
{ 

    class Relatie 
    { 
     public Int32 ID_Persoon { get; set; } 
     public Int32 NestorNrCliënt { get; set; } 

     public Relatie(int ID_Persoon, int NestorNrCliënt) 
     { 
      this.ID_Persoon = ID_Persoon; 
      this.NestorNrCliënt = NestorNrCliënt; 
     } 
    } 

    class nestorDBDataContext 
    { 
     public List<Relatie> tbl_Relaties = new List<Relatie> { 
      new Relatie(15, 27), 
      new Relatie(15, 28), 
      new Relatie(15, 29), 
      new Relatie(15, 30), 
      new Relatie(14, 30), 
      new Relatie(14, 30), 
      new Relatie(14, 30), 
     }; 
    } 

    class Program 
    { 
     public struct Client_Dto{ 
      public Int32 ID; 
     } 

     public static List<Client_Dto> GetClientByBehandelaar(string loggedInUserId) 
     { 
      try 
      { 
       int userID = Convert.ToInt32(loggedInUserId); 
       nestorDBDataContext db = new nestorDBDataContext(); 
       var result = 
        (from relaties in db.tbl_Relaties 
        where relaties.ID_Persoon == userID 
        select new Client_Dto() 
        { 
         ID = relaties.NestorNrCliënt 
        }).ToList(); 
       List<Client_Dto> clienten = result; 
       return clienten; 
      } 
      catch (Exception e) 
      { 
       throw new ArgumentException("GetClientByBehandelaar Failed " + e); 
      } 
     } 

     static void Main(string[] args) 
     { 
      Console.WriteLine(GetClientByBehandelaar("15").Count()); 
      Console.ReadKey(); 
     } 

    } 
} 

也许你需要在这个布尔comarison ID_Persoon == userID

使用的Debug.WriteLine看输出结果为您服务。

Answer 2

试试这个：

int userID = Convert.ToInt32(loggedInUserId); 
     nestorDBDataContext db = new nestorDBDataContext(); 
     List<Client_Dto> clienten = 
      (from relaties in db.tbl_Relaties 
      where relaties.ID_Persoon.Equals(userID) 
      select relaties 
      ).ToList(); 
     return clienten; 

也许它的工作。

Answer 3

public List<Client_Dto> GetClientByBehandelaar(string loggedInUserId) 
    { 
     try 
     { 
      int userID = Convert.ToInt32(loggedInUserId); 
      List<Client_Dto> result = new List<Client_Dto>(); 
      using (nestorDBDataContext db = new nestorDBDataContext()) 
      { 
       IEnumerable<Client_Dto> client_dto = 
        (from relaties in db.tbl_Relaties 
        where relaties.ID_Persoon == userID 
        select relaties); 
       result = client_dto.ToList(); 
       return result; 
      }        
     } 
     catch (Exception e) 
     { 
      throw new ArgumentException("GetClientByBehandelaar Failed " + e); 
     } 
    }