将存储过程转换为LINQ

Question

我正在使用MVC3，但仍在学习LINQ。我在尝试将查询转换为LINQ to Entities时遇到了一些问题。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 

我有几个表，我开始在LINQ中写这篇文章，但我不知道如何正确地返回正确的类型或强制转换它。

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);
}

我将如何为查询传递参数，希望数据以json格式返回。

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);
}

顺便说一句，我故意更正了Employee 的一些拼写

Answer 2

如果这是一个控制器操作，您可能希望通过URL传递ID。此外，在查询之前，不需要在表上调用ToList，在数据库中进行查询，只下拉结果，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 3

这就是您所需要的：

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);
     }

您确定要执行所有这些"ToList<>（）"调用吗？一旦调用"ToList<>（）"，就可以将这三个表全部从数据库中放入内存。如果它们很大，那可能是性能问题。

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);
}

我得到了。。。