Question

I am using entity framework with the following linq query

 IQueryable<Order_Details> query = (from ord in ctx1.Order_Details
                             where ord.OrderID == 1
                             select ord).ToArray();

   gv1.DataSource = query;
   gv1.DataBind();

I get a result ok, return a row with orderId of 1
When I use the following,

var query = (from ord in ctx1.Order_Details
             where ord.OrderID == 1
            select ord).First() as IQueryable<Order_Details>;

gv1.DataSource = query;
gv1.DataBind();

I don’t recive any results in the gridview

Answer 1

First() returns the Order_Detail record itself, not a collection/array, and therefore is not IQueryable; so using as IQueryable<Order_Details> will return null because it can’t be cast. Casting to IQueryable<> can only work for an enumerable of some sort.

If you have to use First, bind to the gridview like this:

var query = (from ord in ctx1.Order_Details
             where ord.OrderID == 1
            select ord).First();

gv1.DataSource = new[] { query };
gv1.DataBind();