He started with the skeleton, dragging buttons and text boxes onto a Windows Form . He called it the "Horizon Billing System." Designing the Face

transaction.Commit() MessageBox.Show("Invoice Saved Successfully!") Me.Close() Catch ex As Exception transaction.Rollback() MessageBox.Show("Error: " & ex.Message) End Try End Using End Sub

❌ – Business logic is often inside form code-behind ( btnSave_Click calls INSERT SQL directly). Unit testing? Zero. Maintenance after 2 years? Painful.

This routine takes inputs from textboxes (Product Name, Price, Quantity) and adds them to a grid.

: YouTube channels like DJ Oamen provide step-by-step visual guides on designing the interface and implementing the underlying code. How to Create Billing System Project in Visual Basic.Net