How to join two tables using linq to sql to retrieve data in asp.net

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I'm trying to join two tables using Linq to sql but, I got error with Object reference not set to an instance of an object. I think because of FirstOrDefault() method, I changed it but the error still !!!

this is my code:

        LblCourseCode.Text = Request.QueryString["CourseCode"];

        try
        {

            var qry = from cs in db.Courses

                      join inst in db.Instructors
                      on cs.CourseId equals inst.CourseId
                      where cs.CourseCode == "@CourseCode"


                      select new 
                      {
                          //cs,
                          //inst


                          cs.CourseCode,
                          cs.CourseName,
                          cs.CourseAbout,
                          cs.CourseObjectives,
                          cs.CourseLearningOut,

                          inst.InstructorName,
                          cs.CourseImgUrl,
                          ////instr = from ins in db.Instructors
                          ////        select new { ins.InstructorName }

                      };

            //LblCourseCode.Text = qry.courseCode;
            LblCourseName.Text = qry.FirstOrDefault().CourseName;
            LblCourseAbout.Text = qry.FirstOrDefault().CourseAbout;
            LblObjectives.Text = qry.FirstOrDefault().CourseObjectives;
            LblLearningOutcomes.Text = qry.FirstOrDefault().CourseLearningOut;
            LblCourseInstructore.Text = qry.FirstOrDefault().InstructorName;

            ImageCourseAb.ImageUrl = qry.FirstOrDefault().CourseImgUrl;

        } 
        catch(Exception ex)
        {
            LblErr.Text = ex.Message;
        }

    }

asked 32 secs ago

Abdullah

1

How to join two tables using linq to sql to retrieve data in asp.net