LINQ Lambda Join Error – cannot be inferred from the usage

I have done this join so many times that I could not figure out why it would not work until I found a post from Justin Niessner here that says “The names of the properties in the anonymous types (as well as their types) must match exactly.” That lead me to this code:

using(var db = new SomeDataContext())
    {
  return db.DemandData
        .Where(demand=> demand.ID == SearchID)
        .Join(db.CUST_ORDER_LINE,
            supply=> new { LINE_NO = supply.LINE, CUST_ORDER_ID = supply.SALES_ORDER_ID },
            demand=> new { demand.LINE_NO, demand.CUST_ORDER_ID },
            (supply, demand) => new { custOrderLineReturn = demand })
        .Select(s => s.custOrderLineReturn )
        .ToList();
    }

In the sixth line I added variables LINE_NO = and CUST_ORDER_ID = that matched the field names in line seven.