Question

I have two tables. One in one database and one in a separate database. I need to populate a dropdown list with options from the first, filtered by the second. I am using Linq-to-SQL. Below is how I pull the “un-filtered” list.

public static DataTable GetSPCCodeList()
{   
   using (var context = ProviderDataContext.Create())
   {
      IQueryable<tblProviderAdminSPCCode> tSPCCode = context.GetTable<tblProviderAdminSPCCode>();
      return (tSPCCode
                 .Where(spcCode => spcCode.Inactive == null)
                 .OrderBy(spcCode => spcCode.SPCCodeID)
                 .Select(spcCode => new 
                                    { spcCode.SPCCodeID, spcCode.SPCDescription, 
                                      spcCode.SPCCategoryID }))
                 .CopyLinqToDataTable();
   }
}

The table I need to filter against simply contains a column for SPCCodeID. How would I go about filtering my List based on if they exist in the second table?

Answer 1

Generate and execute a LINQ query on the other database to get a collection of your SPCCodeIDs into memory variable e.g.

IList<int> spcCodeIDs = /* query goes here */;

Then run your query but replace the Where clause like this

.Where(spcCode => spcCode.Inactive == null
                    && spcCodeIDs.Contains(spcCode.SPCCodeID))