Vbnet+billing+software+source+code

A standard billing application should include:

End Sub

This guide provides a curated list of free, open-source projects, which you can use as both learning tools and functional foundations for your own software. You'll find everything from basic invoicing programs for small shops to more advanced systems with inventory management and reporting. The table below summarizes some of the best free resources available for VB.NET billing software source code.

While the source code above provides a fully functional foundational application, production environments require additional capabilities: vbnet+billing+software+source+code

: Prevent data loss by configuring your application to generate a compressed SQL backup ( .bak file) automatically whenever the administrator closes the application.

Classes managing calculations, validations, and invoice generation. A standard billing application should include: End Sub

MessageBox.Show(billText, "Print Preview") End Sub

Try ' Insert into Invoice Master Dim masterCmd As New SqlCommand("INSERT INTO tbl_Invoice_Master (InvoiceNo, InvoiceDate, CustomerID, SubTotal, TotalCGST, TotalSGST, GrandTotal) VALUES (@invNo, @date, @custId, @sub, @cgst, @sgst, @grand)", conn, transaction) masterCmd.Parameters.AddWithValue("@invNo", txtInvoiceNo.Text) masterCmd.Parameters.AddWithValue("@date", Convert.ToDateTime(txtInvoiceDate.Text)) masterCmd.Parameters.AddWithValue("@custId", cmbCustomer.SelectedValue) masterCmd.Parameters.AddWithValue("@sub", CDec(lblSubtotal.Text)) masterCmd.Parameters.AddWithValue("@cgst", CDec(lblTotalCGST.Text)) masterCmd.Parameters.AddWithValue("@sgst", CDec(lblTotalSGST.Text)) masterCmd.Parameters.AddWithValue("@grand", CDec(lblGrandTotal.Text)) masterCmd.ExecuteNonQuery() While the source code above provides a fully

Imports System.Data.SqlClient Public Class frmBilling ' Temporary runtime table to hold UI cart entries before database commitment Dim cartTable As New DataTable Private Sub frmBilling_Load(sender As Object, e As EventArgs) Handles MyBase.Load InitializeCart() LoadProducts() txtDate.Text = DateTime.Now.ToString("yyyy-MM-dd") End Sub Private Sub InitializeCart() cartTable.Columns.Add("ProductID", GetType(Integer)) cartTable.Columns.Add("Product Name", GetType(String)) cartTable.Columns.Add("Unit Price", GetType(Decimal)) cartTable.Columns.Add("Qty", GetType(Integer)) cartTable.Columns.Add("Total", GetType(Decimal)) dgvInvoice.DataSource = cartTable ' Optimize column layouts for user readability dgvInvoice.Columns("ProductID").Visible = False dgvInvoice.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill End Sub Private Sub LoadProducts() Using conn As SqlConnection = GetConnection() If conn Is Nothing Then Exit Sub Dim cmd As New SqlCommand("SELECT ProductID, ProductName, Price FROM Products", conn) Dim adapter As New SqlDataAdapter(cmd) Dim dt As New DataTable() adapter.Fill(dt) cboProducts.DataSource = dt cboProducts.DisplayMember = "ProductName" cboProducts.ValueMember = "ProductID" End Using End Sub ' Update price box when item choice switches Private Sub cboProducts_SelectedIndexChanged(sender As Object, e As EventArgs) Handles cboProducts.SelectedIndexChanged If TypeOf cboProducts.SelectedValue Is DataRowView Then Exit Sub Using conn As SqlConnection = GetConnection() If conn Is Nothing OrElse Not IsNumeric(cboProducts.SelectedValue) Then Exit Sub Dim cmd As New SqlCommand("SELECT Price FROM Products WHERE ProductID = @ID", conn) cmd.Parameters.AddWithValue("@ID", cboProducts.SelectedValue) Dim price As Object = cmd.ExecuteScalar() If price IsNot Nothing Then txtUnitPrice.Text = Convert.ToDecimal(price).ToString("0.00") End If End Using End Sub ' Push validated item data into runtime memory cart grid Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click If String.IsNullOrEmpty(txtQty.Text) OrElse Not IsNumeric(txtQty.Text) Then MsgBox("Please enter a valid quantity.", MsgBoxStyle.Exclamation, "Validation") Exit Sub End If Dim prodID As Integer = Convert.ToInt32(cboProducts.SelectedValue) Dim prodName As String = cboProducts.Text Dim price As Decimal = Convert.ToDecimal(txtUnitPrice.Text) Dim qty As Integer = Convert.ToInt32(txtQty.Text) Dim total As Decimal = price * qty ' Check if product already exists in cart, update qty if it does Dim existingRow As DataRow() = cartTable.Select("ProductID = " & prodID) If existingRow.Length > 0 Then existingRow(0)("Qty") += qty existingRow(0)("Total") = Convert.ToDecimal(existingRow(0)("Qty")) * price Else cartTable.Rows.Add(prodID, prodName, price, qty, total) End If CalculateInvoiceTotals() txtQty.Clear() End Sub Private Sub CalculateInvoiceTotals() Dim subTotal As Decimal = 0 For Each row As DataRow In cartTable.Rows subTotal += Convert.ToDecimal(row("Total")) For Next Dim taxRate As Decimal = If(IsNumeric(txtTaxRate.Text), Convert.ToDecimal(txtTaxRate.Text), 0D) Dim taxAmount As Decimal = subTotal * (taxRate / 100) Dim grandTotal As Decimal = subTotal + taxAmount txtSubTotal.Text = subTotal.ToString("0.00") txtTaxAmount.Text = taxAmount.ToString("0.00") txtGrandTotal.Text = grandTotal.ToString("0.00") End Sub Private Sub txtTaxRate_TextChanged(sender As Object, e As EventArgs) Handles txtTaxRate.TextChanged CalculateInvoiceTotals() End Sub ' Commit transactions natively across standard tables Private Sub btnSaveInvoice_Click(sender As Object, e As EventArgs) Handles btnSaveInvoice.Click If cartTable.Rows.Count = 0 Then MsgBox("Cart is empty. Cannot save invoice.", MsgBoxStyle.Exclamation, "Validation") Exit Sub End If Using conn As SqlConnection = GetConnection() If conn Is Nothing Then Exit Sub ' Open explicit SQL transaction handler for system safety scope Dim transaction As SqlTransaction = conn.BeginTransaction() Try ' 1. Insert Master Records Dim cmdInvoice As New SqlCommand( "INSERT INTO Invoices (CustomerID, SubTotal, TaxRate, TaxAmount, GrandTotal) " & "VALUES (@CustID, @Sub, @TaxR, @TaxAmt, @Grand); SELECT SCOPE_IDENTITY();", conn, transaction) ' Defaulting safely to Customer ID 1 for walk-ins if empty cmdInvoice.Parameters.AddWithValue("@CustID", 1) cmdInvoice.Parameters.AddWithValue("@Sub", Convert.ToDecimal(txtSubTotal.Text)) cmdInvoice.Parameters.AddWithValue("@TaxR", Convert.ToDecimal(txtTaxRate.Text)) cmdInvoice.Parameters.AddWithValue("@TaxAmt", Convert.ToDecimal(txtTaxAmount.Text)) cmdInvoice.Parameters.AddWithValue("@Grand", Convert.ToDecimal(txtGrandTotal.Text)) Dim newInvoiceID As Integer = Convert.ToInt32(cmdInvoice.ExecuteScalar()) ' 2. Loop & Write Detailed Line Items + Deduct Warehouse Quantities For Each row As DataRow In cartTable.Rows Dim cmdItem As New SqlCommand( "INSERT INTO InvoiceItems (InvoiceID, ProductID, Quantity, UnitPrice, LineTotal) " & "VALUES (@InvID, @ProdID, @Qty, @Price, @LineTotal)", conn, transaction) cmdItem.Parameters.AddWithValue("@InvID", newInvoiceID) cmdItem.Parameters.AddWithValue("@ProdID", row("ProductID")) cmdItem.Parameters.AddWithValue("@Qty", row("Qty")) cmdItem.Parameters.AddWithValue("@Price", row("Unit Price")) cmdItem.Parameters.AddWithValue("@LineTotal", row("Total")) cmdItem.ExecuteNonQuery() ' Deducting Inventory Stock Quantities Dim cmdStock As New SqlCommand( "UPDATE Products SET StockQuantity = StockQuantity - @Qty WHERE ProductID = @ProdID", conn, transaction) cmdStock.Parameters.AddWithValue("@Qty", row("Qty")) cmdStock.Parameters.AddWithValue("@ProdID", row("ProductID")) cmdStock.ExecuteNonQuery() Next transaction.Commit() MsgBox("Invoice #" & newInvoiceID & " successfully generated and saved!", MsgBoxStyle.Information, "Success") ClearForm() Catch ex As Exception transaction.Rollback() MsgBox("Transaction processing failed. Structural rollback applied." & vbCrLf & ex.Message, MsgBoxStyle.Critical, "Error") End Try End Using End Sub Private Sub ClearForm() cartTable.Rows.Clear() txtSubTotal.Clear() txtTaxAmount.Clear() txtGrandTotal.Clear() txtTaxRate.Text = "0" End Sub End Class Use code with caution. Security & Optimization Best Practices

: Designing Windows Forms with controls like text boxes, combo boxes for item selection, and data grid views for displaying records.

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

Creating a billing software in typically involves setting up a database (like SQL Server), designing a Windows Form interface, and writing logic for calculations and invoice generation.

: SQL Server is frequently used for enterprise-level data, while MS Access or SQLite may be used for simpler, lightweight applications.