Can I join a table to a list using linq? [duplicate]

You probably found out that you can’t join an Entity Framework LINQ query with a local list of entity objects, because it can’t be translated into SQL. I would preselect the database data on the account numbers only and then join in memory.

var accountNumbers = lstFarmerProfiles.Select(x => x.AccountNo).ToArray();

var duplicationChecklist = 
        from profile in dataAccessdup.MST_FarmerProfile
                                     .Where(p => accountNumbers
                                                    .Contains(p.AccountNo))
                                     .AsEnumerable() // Continue in memory
        join param in lstFarmerProfiles on 
            new { profile.Name, profile.AccountNo} equals 
            new { param.Name, param.AccountNo}
        select profile

So you will never pull the bulk data into memory but the smallest selection you can probably get to proceed with.

If accountNumbers contains thousands of items, you may consider using a better scalable chunky Contains method.