Access list using LINQ in SharePoint

Question

I am going to access SharePoint list using LINQ and load to grid. I have Employees and Projects lists in share point site.

I've found some code here

private void BindGrid()
        {
            SPLinqDataContext dc = new SPLinqDataContext(SPContext.Current.Web.Url);
            EntityList<EmployeesItem> Employees = dc.GetList<EmployeesItem>("Employees");

            var EmployeeQuery = from e in Employees.ToList()
                                select new
                                {
                                    e.Title,
                                    e.FirstName,
                                    Position = e.Position.Title,
                                    PositionDescription = e.Position.Description,
                                    Department = e.Position.Department.Title
                                };
            GridView1.DataSource = EmployeeQuery;
            GridView1.DataBind();
        }

My problem is regarding <EmployeesItem>. Is this inherits with my reference? or should I suppose to create a separate class in .net as we normally do?

note - I mean reference is: We should generate the LINQ to SharePoint proxy code in order to use LINQ. spmetal.exe /web:http://localhost/sites/MySampleWebSite /namespace:AccessSPDatawithLINQ.VisualWebPart1 /code:SPLinq.cs

Answer 1

To my understanding

Point 1: You will execute your LINQ query and you will read complete SPList Employees from sharepoint to List<EmployeesItem> in memory. Now I don't know if you modify these EmployeesItem, will that reflect in your SP list? You can test this yourself.

Point 2: Here you are creating a Anonymous type. If you modify this object, it will not modify your EmployeesItem object.

Point 3: Here you have in memory query, which has IEnumerable of Anonymous type. Unless and until you evaluate this IEnumerable (by doing .ToList()), your EmployeeQuery will not execute. As of now, according to your code, when you do .DataBind(); your EmployeeQuery will execute.

private void BindGrid()
{
   SPLinqDataContext dc = new SPLinqDataContext(SPContext.Current.Web.Url);
   EntityList<EmployeesItem> Employees = dc.GetList<EmployeesItem>("Employees");

   var EmployeeQuery = from e in Employees.ToList() //Point 1
                       select new                   //Point 2
                       {
                           Title = e.Title,
                           FirstName = e.FirstName,
                           Position = e.Position.Title,
                           PositionDescription = e.Position.Description,
                           Department = e.Position.Department.Title
                       };
   GridView1.DataSource = EmployeeQuery;            //Point 3
   GridView1.DataBind();

}

Hope this helps.