c# - Want to populate a combobox with two related tables in access -

i have 2 related tables in access database, table1 , table2. in table1 have "cd_table1"(primarykey) , "cd_table2"(foreignkey). in table2 have "cd_table2"(primarykey) , "nm_atr"(string). want populate combobox these 2 tables, "displaymemberpath" needs "nm_atr" , "valuememberpath" needs "cd_table1".

my code:

oledbcommand cmd = new oledbcommand("select table1.cd_atributosnormais, table1.nm_atr, table2.cd_atributosnormais table1, table2 table1.cd_atributosnormais = table2.cd_atributosnormais", cn);             oledbdatareader reader = cmd.executereader();             datatable table = new datatable();             table.load(reader);             datarow row = table.newrow();             row["nm_atr"] = "";             table.rows.insertat(row, 0);              this.btcmbatkbaatr1.datacontext = table.defaultview;             this.btcmbatkbaatr1.displaymemberpath = "nm_atr";             this.btcmbatkbaatr1.selectedvaluepath = "cd_atributosnormais";             cmd.executenonquery();             reader.close();             reader.dispose();         }         catch(exception ex)         {             messagebox.show(ex.message);         }                 {             cn.close();             cn.dispose();         } 

where error , why combobox not display nothing? i'm opened connection , i'm using c# program , access 2010.

try if helps..

oledbcommand cmd = new oledbcommand("select table1.cd_atributosnormais cd_atributosnormais, table2.nm_atr nm_atr table1 left outer join table2 on table1.cd_atributosnormais = table2.cd_atributosnormais", cn);             oledbdatareader reader = cmd.executereader();             datatable table = new datatable();             table.load(reader);             datarow row = table.newrow();             row["nm_atr"] = "";             table.rows.insertat(row, 0);              this.btcmbatkbaatr1.datacontext = table.defaultview;             this.btcmbatkbaatr1.displaymemberpath = "nm_atr";             this.btcmbatkbaatr1.selectedvaluepath = "cd_atributosnormais";             cmd.executenonquery();             reader.close();             reader.dispose();         }         catch(exception ex)         {             messagebox.show(ex.message);         }                 {             cn.close();             cn.dispose();         }