Question

我正在使用MVC3并仍在学习LINQ。我在尝试将查询转换为LINQ到实体时遇到了一些麻烦。我想返回一个Json方法

我的存储过程

Create Procedure [dbo].[ResourceReports]
(
    @EmployeeID int
) 
as
begin
    select   p.projectName AS Projects,  count( b.[CreatedByID]) AS Bugs
    from [EmployeeDetails] e inner join [Bugs] b  on e.[EmployeId] = b.[CreatedByID]
    inner join Projects p on b.ProjectId = p.ProjectId
    where e.[EmployeId] = @EmployeeID   
    group by P.projectName
end

我有几张桌子，我开始在LINQ中写出这个，但我不确定如何正确地返回正确的类型或投射它。

我的控制器

public JsonResult Getchart()
{
    var Bug = db.Bugs.ToList<Bug>();
    var EmployeDetails = db.EmployeeDetails.ToList<EmployeeDetail>();
    var projects = db.Projects.ToList<Project>();

    var result = (from e in EmployeDetails 
                  join b in Bug on e.EmployeId equals b.CreatedByID
                  join p in projects on b.ProjectId equals p.ProjectId
                  where e.EmployeId = @EmployeId
                  group p.projectName
                  select new (p.projectName as Project ,count(b.CreatedByID) as Bug)).Take(50);

    return Json(result,JsonRequestBehavior.AllowGet);
}

如何将参数传递给查询，希望以json格式返回数据。

Answer 1

假设您可以将值作为参数传递给方法：

public JsonResult Getchart(int employeeId)
{
    var Bug = db.Bugs.ToList<Bug>();
    var EmployeeDetails = db.EmployeeDetails.ToList<EmployeeDetail>();
    var projects = db.Projects.ToList<Project>();

    var result = (from e in EmployeeDetails 
                  join b in Bug on e.EmployeeId equals b.CreatedByID
                  join p in projects on b.ProjectId equals p.ProjectId
                  where e.EmployeeId == employeeId   // <-- use the parameter here
                  group p by p.projectName into g
                  select new {
                     Project = g.Key,
                     Bug = g.Count() 
                     }
                 ).Take(50);
    return Json(result,JsonRequestBehavior.AllowGet);
}

BTW我有意纠正了Employee

的一些拼写

Answer 2

这是你需要的：

public JsonResult Getchart(int employeId)
  {
        var Bug = db.Bugs.ToList<Bug>();
        var EmployeDetails = db.EmployeeDetails.ToList<EmployeeDetail>();
        var projects = db.Projects.ToList<Project>();

       var result =   (from e in EmployeDetails 
                      join b in Bug on e.EmployeId equals b.CreatedByID
                      join p in projects on b.ProjectId equals p.ProjectId
                      where e.EmployeId == employeeId
                      group p.projectName
                     select new (p.projectName as Project ,count(b.CreatedByID) as Bug)).Take(50);
                       return Json(result,JsonRequestBehavior.AllowGet);
     }

您确定要完成所有这些＆＃34; ToList＆lt;＆gt;（）＆＃34;电话？一旦调用＆＃34; ToList＆lt;＆gt;（）＆＃34;，就可以将这三个表从数据库中带入内存。如果它们很大，那可能是性能问题。

Answer 3

如果这是控制器操作，您可能希望通过URL传递ID。此外，在查询之前无需在表上调用ToList，在数据库中执行查询并仅下拉结果，例如。

public JsonResult GetChart(int employeeId) { var query = (from e in db.EmployeeDetails join b in db.Bugs on e.EmployeeId equals b.CreatedById join p in db.Projects on b.ProjectId equals p.ProjectId where e.EmployeeId == employeeId group new {p, b} by new { p.ProjectName } into g select new { Project = g.Key.Name, Bugs = g.Count() }).Take(50); return Json(query.ToList(), JsonRequestBehaviour.AllowGet); }

Answer 4

public JsonResult GetChart()
            {
                //int employeeId
              var Bug = db.Bugs.ToList<Bug>();
              var EmployeDetails = db.EmployeeDetails.ToList<EmployeeDetail>();
              var projects = db.Projects.ToList<Project>();

              var query = (from e in EmployeDetails
                           join b in Bug on e.EmployeId equals b.CreatedByID
                           join p in projects on b.ProjectId equals p.ProjectId
                           where e.EmployeId == 1
                           group new { p, b } by new
                           {
                               p.projectName
                           } into g
                           select new ChartModel
                           {
                               ProjectName = g.Key.projectName,                     

                               bug = g.Count()
                           }).ToList();
              return Json(query, JsonRequestBehavior.AllowGet);
}

我有......

将存储过程转换为LINQ

4 个答案: