Question

I am trying to join a table and a list in LINQ. From posts on stackoverflow, I know that you can’t select from a table and a list using a join–that you have to use .contains. But when I use .contains I get the same error. What else am I missing? Am I trying to do something that Linq won’t support? Should I just write a supporter function that will loop through the dailyTotal records one-by-one (eliminating the need for a join)?

This is my code:

Dim count = (from sqlRec in mydatacontext.table, listItem in myList where _ 
    sqlRec.guidIdField.ToString.contains(listItem.IdProperty.toString select sqlRec).count

It gives the same error I was trying to fix, which reads: “Local sequence cannot be used in LINQ to SQL implementations of query operators except the Contains operator.”

I am trying to do this (of course, the syntax below won’t work):

(from sqlRec in table, listItem in List where sqlRec.guid=listId.Id select sqlRec).count

Answer 1

You have to use Contains on the local sequence:

Dim count = mydatacontext.table.Where(Function(sqlRec) _
                myList.[Select](Function(x) _ 
                   listItem.IdProperty.ToString()) _
                .Contains(sqlRec.guidIdField.ToString())).Count()