// display ProductSuppliers by DB method, passing through the productID inherited from main form private List <Products_Suppliers> DisplayProductSupplier() { lstSuppliers.Items.Clear(); List <Products_Suppliers> productSuppliers = Products_SuppliersDB.ProductSuppliers((int)prodId); foreach (Products_Suppliers psup in productSuppliers) { lstSuppliers.Items.Add(psup); } return(productSuppliers); }