LINQ lambda - convert int to string

Question

i'm trying to compare a int with a string in the join method of linq lambda, like this:

database.booking.Join(database.address,
                      book => book.bookno,
                      afh => afh.addressid.ToString(),
                       (book, afh) => new { booking = book, add = afh })
                .Where(book => book.address.name == "test");

but i'm getting an error on the ToString():

System.NotSupportedException: LINQ to Entities does not recognize the method 'Int32 ToInt32(System.String)' method, and this method cannot be translated into a store expression.

How do i solve this?

Answer 1

Are you working with Linq to SQL? Linq is trying to convert your lambda to sql query. Unfortunately, ToString is not so easily supported.

You can materialize your tables with ToArray() before join, but it can be expensive.

Look at this article and this question.

Answer 2

Try this:

var bookinger = database.booking.Join(database.address,
                         book => book.bookno,
                         afh => afh.addressid,
                         (book, afh) =>
                         new { booking = book, add = afh })
                     .Where(book => book.address.name == "test")
                     .Select(new { booking, add = add.ToString() });

Answer 3

Have you tried this??

var bookinger = 
    database.booking.Join(database.address,
        book => book.bookno,
        afh => Convert.ToString(afh.addressid),
        (book, afh) =>
        new { booking = book, add = afh })
    .Where(book => book.address.name == "test");