c# - Dynamic linq query with join -

here try of dynamic linq query join. try list of unique categories, brands , other criteria present in last reading in database. passed query (brand, category etc.) defined @ runtime.

i read best way of doing func's, predicates etc., think beyond capacity @ stage. i'm trying easier way query string, got working simpler case, i'm doing wrong here join. if plain select product.category intellisense of course works, not in string in select clause.

  public ienumerable<string> getfilteritems(string dbcolumn)     {         var filteritems = new list<string>();          return (from reading in helper.latestreadings                 reading.distributor != helper.client                 join product in helper.context.products                        on reading.productid equals product.skucode                 select ("product." + dbcolumn)).distinct();     } 

you can use reflection achieve this

public ienumerable<string> getfilteritems(string dbcolumn)     {         var filteritems = new list<string>();          var productlist = reading in helper.latestreadings                 reading.distributor != helper.client                 join product in helper.context.products                        on reading.productid equals product.skucode                 select product;          return productlist.select(x=>x.gettype().getproperty(dbcolumn).getvalue(x)).cast<string>().distinct(); }