Question

I’m having issues after merging 2 LINQ lists. I get the following error: the query contains reference to items defined on a different data context.

This is how I constructed my final 2 LINQ lists:

CAPDBDataContext CAdb = new CAPDBDataContext();
USPDBDataContext USdb = new USPDBDataContext();

var ExceptionList = Special_texts.Where(x => x.name.Equals("ExceptionList"))
                    .Select(x => x.special_text1)
                    .AsEnumerable()
                    .Select(x => x.Split(new[] { '#' }, StringSplitOptions.RemoveEmptyEntries))
                    .SelectMany(x => x)
                    .ToList();

var USquery = from uscomp in USdb.UScompanies
              join ussect in USdb.USsectors
              on uscomp.sector_code equals ussect.sector_code
              select new
              {
                  uscomp.company_name,
                  uscomp.primary_exchange,
                  ussect.description
              };

var CAtemp = from x in CAdb.companies
             where !ShefalisList.Contains(x.ticker)
             select x;

var CAquery = from temp in CAtemp
             join casect in CAdb.sectors
             on temp.sector_code equals casect.sector_code
             select new
             {                          
                 temp.company_name,
                 temp.primary_exchange,                             
                 casect.description
             };

 var mergedList = USquery.Union(CAquery).ToList();

What am I doing wrong?

Answer 1

Do this instead:

var mergedList = USquery.AsEnumerable().Union(CAquery).ToList()

You can’t Union queries over different databases without getting their results into memory.