Vb.net Billing Software Source Code !exclusive! 🌟

graphicEngine.DrawString($"Subtotal: $txtSubTotal.Text", fontNormal, Brushes.Black, coordinateX + 180, coordinateY)coordinateY += rowOffsetgraphicEngine.DrawString($"Tax (15%): $txtTax.Text", fontNormal, Brushes.Black, coordinateX + 180, coordinateY)coordinateY += rowOffsetgraphicEngine.DrawString($"Discount: $txtDiscountInput.Text", fontNormal, Brushes.Black, coordinateX + 180, coordinateY)coordinateY += rowOffsetgraphicEngine.DrawString($"Grand Total: $txtGrandTotal.Text", fontBold, Brushes.Black, coordinateX + 180, coordinateY)

Imports System.Data.SqlClient Imports System.Drawing.Printing Public Class FormBilling ' Define your SQL Server database connection string Dim connString As String = "Server=(localdb)\MSSQLLocalDB;Database=BillingDB;Trusted_Connection=True;" Dim conn As New SqlConnection(connString) ' Structure to hold temporary printing data Private invoiceIdToPrint As Integer = 0 Private Sub FormBilling_Load(sender As Object, e As EventArgs) Handles MyBase.Load LoadProducts() ResetForm() End Sub ''' ''' Fetches active items from the database and binds them to the product selection ComboBox. ''' Private Sub LoadProducts() Try Dim query As String = "SELECT ProductID, ProductName, Price FROM Products ORDER BY ProductName ASC" Dim adapter As New SqlDataAdapter(query, conn) Dim dt As New DataTable() adapter.Fill(dt) cmbProducts.DataSource = dt cmbProducts.DisplayMember = "ProductName" cmbProducts.ValueMember = "ProductID" cmbProducts.SelectedIndex = -1 txtPrice.Clear() Catch ex As Exception MessageBox.Show("Error loading products: " & ex.Message, "Database Error", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try End Sub ' Update the price field automatically when a product is selected Private Sub cmbProducts_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cmbProducts.SelectedIndexChanged If cmbProducts.SelectedIndex <> -1 AndAlso TypeOf cmbProducts.SelectedValue Is DataRowView = False Then Dim drv As DataRowView = CType(cmbProducts.SelectedItem, DataRowView) txtPrice.Text = Convert.ToDecimal(drv("Price")).ToString("F2") txtQuantity.Text = "1" End If End Sub ''' ''' Adds the selected product and quantity into the DataGridView cart. ''' Private Sub btnAddItem_Click(sender As Object, e As EventArgs) Handles btnAddItem.Click If cmbProducts.SelectedIndex = -1 Then MessageBox.Show("Please select a product first.", "Input Validation", MessageBoxButtons.OK, MessageBoxIcon.Warning) Exit Sub End If Dim qty As Integer If Not Integer.TryParse(txtQuantity.Text, qty) OrElse qty <= 0 Then MessageBox.Show("Please enter a valid quantity greater than zero.", "Input Validation", MessageBoxButtons.OK, MessageBoxIcon.Warning) Exit Sub End If Dim prodId As Integer = Convert.ToInt32(cmbProducts.SelectedValue) Dim prodName As String = cmbProducts.Text Dim price As Decimal = Convert.ToDecimal(txtPrice.Text) Dim total As Decimal = price * qty ' Check if product already exists in the cart grid; if so, update quantity Dim itemExists As Boolean = False For Each row As DataGridViewRow In dgvInvoice.Rows If Convert.ToInt32(row.Cells("ProdID").Value) = prodId Then Dim currentQty As Integer = Convert.ToInt32(row.Cells("Qty").Value) row.Cells("Qty").Value = currentQty + qty row.Cells("Total").Value = (currentQty + qty) * price itemExists = True Exit For End If Next ' If item is unique to the current session, add it as a new row If Not itemExists Then dgvInvoice.Rows.Add(prodId, prodName, price.ToString("F2"), qty, total.ToString("F2")) End If CalculateInvoiceTotals() txtQuantity.Text = "1" cmbProducts.SelectedIndex = -1 txtPrice.Clear() End Sub ''' ''' Calculates Subtotal, Taxes, Discounts, and the final Grand Total in real-time. ''' Private Sub CalculateInvoiceTotals() Dim subTotal As Decimal = 0 For Each row As DataGridViewRow In dgvInvoice.Rows subTotal += Convert.ToDecimal(row.Cells("Total").Value) Next Dim taxPercent As Decimal = 0 Decimal.TryParse(txtTax.Text, taxPercent) Dim discountAmt As Decimal = 0 Decimal.TryParse(txtDiscount.Text, discountAmt) Dim taxAmount As Decimal = subTotal * (taxPercent / 100) Dim grandTotal As Decimal = (subTotal + taxAmount) - discountAmt txtSubTotal.Text = subTotal.ToString("F2") txtGrandTotal.Text = grandTotal.ToString("F2") End Sub ' Live calculation events when dynamic variables change Private Sub txtTax_TextChanged(sender As Object, e As EventArgs) Handles txtTax.TextChanged, txtDiscount.TextChanged CalculateInvoiceTotals() End Sub ''' ''' Validates UI input, saves transactions safely to database tables, updates stock, and prints. ''' Private Sub btnSavePrint_Click(sender As Object, e As EventArgs) Handles btnSavePrint.Click If String.IsNullOrWhiteSpace(txtCustomerName.Text) Then MessageBox.Show("Customer Name is required.", "Validation Error", MessageBoxButtons.OK, MessageBoxIcon.Warning) Exit Sub End If If dgvInvoice.Rows.Count = 0 Then MessageBox.Show("Cart is empty. Please add items to process the invoice.", "Validation Error", MessageBoxButtons.OK, MessageBoxIcon.Warning) Exit Sub End If Dim insertedInvoiceId As Integer = 0 ' Initialize SQL transaction logic for accurate state commitment Using connection As New SqlConnection(connString) connection.Open() Using transaction As SqlTransaction = connection.BeginTransaction() Try ' Insert Master Invoice Records Dim queryInvoice As String = "INSERT INTO Invoices (CustomerName, SubTotal, TaxAmount, Discount, GrandTotal) " & "OUTPUT INSERTED.InvoiceID " & "VALUES (@Customer, @Sub, @Tax, @Disc, @Grand);" Using cmdInv As New SqlCommand(queryInvoice, connection, transaction) cmdInv.Parameters.AddWithValue("@Customer", txtCustomerName.Text.Trim()) cmdInv.Parameters.AddWithValue("@Sub", Convert.ToDecimal(txtSubTotal.Text)) Dim taxPercent As Decimal = 0 Decimal.TryParse(txtTax.Text, taxPercent) Dim calculatedTaxObj As Decimal = Convert.ToDecimal(txtSubTotal.Text) * (taxPercent / 100) cmdInv.Parameters.AddWithValue("@Tax", calculatedTaxObj) cmdInv.Parameters.AddWithValue("@Disc", Convert.ToDecimal(txtDiscount.Text)) cmdInv.Parameters.AddWithValue("@Grand", Convert.ToDecimal(txtGrandTotal.Text)) insertedInvoiceId = CInt(cmdInv.ExecuteScalar()) End Using ' Insert Item Details & Update Live Inventory Counts For Each row As DataGridViewRow In dgvInvoice.Rows Dim pid As Integer = Convert.ToInt32(row.Cells("ProdID").Value) Dim prc As Decimal = Convert.ToDecimal(row.Cells("Price").Value) Dim qty As Integer = Convert.ToInt32(row.Cells("Qty").Value) Dim tot As Decimal = Convert.ToDecimal(row.Cells("Total").Value) ' 1. Write transactional line item records Dim queryDetails As String = "INSERT INTO InvoiceDetails (InvoiceID, ProductID, Price, Quantity, Total) " & "VALUES (@InvID, @ProdID, @Price, @Qty, @Tot);" Using cmdDet As New SqlCommand(queryDetails, connection, transaction) cmdDet.Parameters.AddWithValue("@InvID", insertedInvoiceId) cmdDet.Parameters.AddWithValue("@ProdID", pid) cmdDet.Parameters.AddWithValue("@Price", prc) cmdDet.Parameters.AddWithValue("@Qty", qty) cmdDet.Parameters.AddWithValue("@Tot", tot) cmdDet.ExecuteNonQuery() End Using ' 2. Deduct active stock levels safely Dim queryStock As String = "UPDATE Products SET StockQty = StockQty - @Qty WHERE ProductID = @ProdID" Using cmdStock As New SqlCommand(queryStock, connection, transaction) cmdStock.Parameters.AddWithValue("@Qty", qty) cmdStock.Parameters.AddWithValue("@ProdID", pid) cmdStock.ExecuteNonQuery() End Using Next ' Commit structural items if both operations pass successfully transaction.Commit() invoiceIdToPrint = insertedInvoiceId MessageBox.Show("Invoice saved successfully with ID: " & invoiceIdToPrint, "Success", MessageBoxButtons.OK, MessageBoxIcon.Information) ' Trigger Printing Routine TriggerReceiptPrinting() ResetForm() Catch ex As Exception transaction.Rollback() MessageBox.Show("Transaction failed and was rolled back: " & ex.Message, "System Error", MessageBoxButtons.OK, MessageBoxIcon.Error) End Try End Using End Using End Sub ''' ''' Configures standard .NET printing subroutines. ''' Private Sub TriggerReceiptPrinting() Try Use code with caution.

+------------------+ +------------------+ | Customers | | Products | +------------------+ +------------------+ | CustomerID (PK) | | ProductID (PK) | | CustomerName | | ProductName | | Phone | | Price | | TotalBalance | | StockQuantity | +--------+---------+ +--------+---------+ | | | 1 | 1 | | | 0..* | 0..* +--------v---------+ +--------v---------+ | Invoices | | InvoiceDetails | +------------------+ +------------------+ | InvoiceNo (PK) | 1 0..* | ID (PK) | | InvoiceDate |---------------> InvoiceNo (FK) | | CustomerID (FK) | | ProductID (FK) | | GrossAmount | | Quantity | | TaxAmount | | UnitPrice | | NetAmount | | TotalPrice | +------------------+ +------------------+ SQL Schema Definition

A DataGridView control named dgvInvoiceItems containing columns: Product ID , Product Name , Unit Price , Quantity , and Total Price . vb.net billing software source code

Dim startX As Integer = 50Dim startY As Integer = 50Dim offset As Integer = 40

-- Create the Database CREATE DATABASE BillingDB; GO USE BillingDB; GO -- 1. Products Table CREATE TABLE Products ( ProductID INT IDENTITY(1,1) PRIMARY KEY, ProductName VARCHAR(100) NOT NULL, Price DECIMAL(18,2) NOT NULL, StockQty INT NOT NULL ); -- 2. Invoices Master Table CREATE TABLE Invoices ( InvoiceID INT IDENTITY(1,1) PRIMARY KEY, InvoiceDate DATETIME DEFAULT GETDATE(), CustomerName VARCHAR(100) NOT NULL, SubTotal DECIMAL(18,2) NOT NULL, TaxAmount DECIMAL(18,2) NOT NULL, Discount DECIMAL(18,2) NOT NULL, GrandTotal DECIMAL(18,2) NOT NULL ); -- 3. Invoice Items Transaction Table CREATE TABLE InvoiceDetails ( DetailID INT IDENTITY(1,1) PRIMARY KEY, InvoiceID INT FOREIGN KEY REFERENCES Invoices(InvoiceID) ON DELETE CASCADE, ProductID INT FOREIGN KEY REFERENCES Products(ProductID), Price DECIMAL(18,2) NOT NULL, Quantity INT NOT NULL, Total DECIMAL(18,2) NOT NULL ); Use code with caution. 2. User Interface Design (WinForms)

Seamless integration with SQL Server, Access, and MySQL via ADO.NET. graphicEngine

''' ''' Draws the physical receipt visual layout using standard drawing canvases.''' Private Sub PrintReceiptPage(sender As Object, e As PrintPageEventArgs)Dim fontTitle As New Font("Arial", 16, FontStyle.Bold)Dim fontHeader As New Font("Arial", 11, FontStyle.Bold)Dim fontBody As New Font("Arial", 10, FontStyle.Regular)

Place this code directly behind your primary user interface form.

#Region "Printing Engine Routines"Private Sub PrintInvoiceReceipt()Dim printDoc As New PrintDocument()AddHandler printDoc.PrintPage, AddressOf PrintPageHandler Dim startX As Integer = 50Dim startY As

: Create unlimited professional invoices with unique reference numbers.

Windows Forms for data entry, item scanning, and invoice rendering.

Initialize SQL Server and run the structural database schema script.

for backend data management. The software's primary architecture follows an object-oriented approach where business logic (calculations and tax rules) is separated from the presentation layer (forms and buttons). 1. Core Architectural Modules