直接从控制器运行SQL存储过程

I have this stored procedure in sql-server.

CREATE PROCEDURE current_call
    -- Add the parameters for the stored procedure here
    @call_id int
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    -- Insert statements for procedure here
    SELECT dbo.Call.call_id, dbo.Call.city, dbo.Call.call_received, dbo.Call.call_transfer, dbo.Call.call_response, dbo.Call.call_depart, dbo.Call.call_arrive, dbo.Call.call_return, dbo.Call.call_end, dbo.Priority.name AS priorityName, dbo.Call_Status.name as Call_Status, 
                  dbo.Station.station_name, dbo.City.city_name, dbo.Protocol.name AS protocolName
FROM     dbo.City INNER JOIN
                  dbo.Call INNER JOIN
                  dbo.Priority ON dbo.Call.priority = dbo.Priority.priority_id ON dbo.City.city_id = dbo.Call.city INNER JOIN
                  dbo.Protocol ON dbo.Call.protocol_category = dbo.Protocol.id LEFT OUTER JOIN
                  dbo.Station INNER JOIN
                  dbo.Ambulance ON dbo.Station.station_id = dbo.Ambulance.ambulance_station ON dbo.Call.amb_id = dbo.Ambulance.ambulance_id
                  INNER JOIN
                  dbo.Call_Status ON dbo.Call.call_status = dbo.Call_Status.call_status_id

WHERE dbo.Call.call_id=@call_id;
END
GO

I'm trying to call it through a controller and print the retrieved fields as a json string with no luck!

这是我的控制器：

public System.Web.Http.Results.JsonResult<String> GetTwo(int c_id)
        {
            using (EMSMVCEntities entities = new EMSMVCEntities())
            {
                entities.Configuration.ProxyCreationEnabled = false;
                var query = entities.Database.SqlQuery<ObjectResult>("exec [dbo].[current_call] @call_id", new SqlParameter("call_id", c_id)).ToList();

                return Json (query.ToString());
            }
        }

但是，出现以下错误：

System.InvalidOperationException：'结果类型   'System.Data.Entity.Core.Objects.ObjectResult'可能不是抽象的，   必须包含默认构造函数。”

I also tried the following code and the result was "-1"

var query = entities.Database.ExecuteSqlCommand("exec [dbo].[current_call] @call_id", new SqlParameter("call_id", c_id)).toString();