Entity Framework Join 3 Tables

Solution 1:

I think it will be easier using syntax-based query:

var entryPoint = (from ep in dbContext.tbl_EntryPoint
                 join e in dbContext.tbl_Entry on ep.EID equals e.EID
                 join t in dbContext.tbl_Title on e.TID equals t.TID
                 where e.OwnerID == user.UID
                 select new {
                     UID = e.OwnerID,
                     TID = e.TID,
                     Title = t.Title,
                     EID = e.EID
                 }).Take(10);

And you should probably add orderby clause, to make sure Top(10) returns correct top ten items.

Solution 2:

This is untested, but I believe the syntax should work for a lambda query. As you join more tables with this syntax you have to drill further down into the new objects to reach the values you want to manipulate.

var fullEntries = dbContext.tbl_EntryPoint
    .Join(
        dbContext.tbl_Entry,
        entryPoint => entryPoint.EID,
        entry => entry.EID,
        (entryPoint, entry) => new { entryPoint, entry }
    )
    .Join(
        dbContext.tbl_Title,
        combinedEntry => combinedEntry.entry.TID,
        title => title.TID,
        (combinedEntry, title) => new 
        {
            UID = combinedEntry.entry.OwnerUID,
            TID = combinedEntry.entry.TID,
            EID = combinedEntry.entryPoint.EID,
            Title = title.Title
        }
    )
    .Where(fullEntry => fullEntry.UID == user.UID)
    .Take(10);