public void SavePurchaseItem()
{
string productID = ProductIDTextBox.Text;
string productDesc = ProductDescTextBox.Text;
string purchasePrice = PriceTextBox.Text;
string primeCategory = GetSelectedPrimeCategory();
string secondaryCategory = GetSelectedSecCategory();
string customerID = GetSelectedCustomerID();
string purchaseDate = GetDate();
DataManager dataManager = new DataManager(connectionString);
dataManager.InsertPurchaseItem(productID,productDesc,purchasePrice,primeCategory,
secondaryCategory,customerID,purchaseDate,poNumber);
}