private void PurchaseForm_Load(object sender, EventArgs e)
        {
            try
            {
                supplierComboBox.DataSource = _purchaseManager.SupplierComboLoad();
                supplierComboBox.Text       = "-Select-";

                categoryComboBox.DataSource = _purchaseManager.CategoryComboLoad();
                categoryComboBox.Text       = "-Select-";

                productsComboBox.Enabled = false;
                productsComboBox.Text    = "-Select-";

                ResetErrorLabels();
                deleteButton.Visible = false;
                cancelButton.Visible = false;

                DisplayRecords(GetRecords(), _database);
                confirmationLabel.Text = "Your Purchase History";
            }
            catch (Exception error)
            {
                ExceptionMessage(error);
            }
        }
        private void PurchasessUI_Load(object sender, EventArgs e)
        {
            supplierComboBox.DataSource = _PurchaseManager.SupplierComboLoad();
            supplierComboBox.Text       = "-Select-";

            categoryComboBox.DataSource = _PurchaseManager.CategoryComboLoad();
            categoryComboBox.Text       = "-Select-";

            productsComboBox.DataSource = _PurchaseManager.ProductComboLoad(Convert.ToInt32(categoryComboBox.SelectedValue));
            productsComboBox.Text       = "-Select-";
        }