Use
where list.Contains(item.Property)
Or in your case:
var foo = from codeData in channel.AsQueryable<CodeData>()
where codeIDs.Contains(codeData.CodeId)
select codeData;
But you might as well do that in dot notation:
var foo = channel.AsQueryable<CodeData>()
.Where(codeData => codeIDs.Contains(codeData.CodeId));