Vb.net Billing Software Source Code -

Public Sub CloseDB() If conn.State = ConnectionState.Open Then conn.Close() End If End Sub End Module Private Sub btnAddProduct_Click(sender As Object, e As EventArgs) Handles btnAddProduct.Click Try OpenDB() Dim query As String = "INSERT INTO tbl_Product (ProductCode, ProductName, Unit, SellingPrice, GST_Percent, StockQuantity) VALUES (@code, @name, @unit, @price, @gst, @stock)" cmd = New SqlCommand(query, conn) cmd.Parameters.AddWithValue("@code", txtCode.Text) cmd.Parameters.AddWithValue("@name", txtName.Text) cmd.Parameters.AddWithValue("@unit", cmbUnit.Text) cmd.Parameters.AddWithValue("@price", Convert.ToDecimal(txtPrice.Text)) cmd.Parameters.AddWithValue("@gst", Convert.ToDecimal(txtGST.Text)) cmd.Parameters.AddWithValue("@stock", Convert.ToDecimal(txtStock.Text)) cmd.ExecuteNonQuery() MessageBox.Show("Product saved successfully.") LoadProductsDataGrid() Catch ex As Exception MessageBox.Show("Error: " & ex.Message) Finally CloseDB() End Try End Sub 3. The Billing Engine – Calculating Invoice Totals Inside your frmBillEntry.vb :

Remember: the best source code is the one you understand and can modify. Download a working project, dissect its Form_Load , CalculateTotals , and SaveInvoice methods, and tailor it to your local tax laws and workflow. vb.net billing software source code

' Assume GST is stored per product Dim gstPercent As Decimal = Convert.ToDecimal(row.Cells("GSTPercent").Value) Dim lineAmount As Decimal = Convert.ToDecimal(row.Cells("Amount").Value) totalTax += (lineAmount * gstPercent / 100) Next Public Sub CloseDB() If conn

Imports System.Data.SqlClient Module modDatabase Public conn As SqlConnection Public cmd As SqlCommand Public da As SqlDataAdapter Public dt As DataTable ' Assume GST is stored per product Dim

-- 3. Invoice Master table CREATE TABLE tbl_Invoice_Master ( InvoiceNo INT PRIMARY KEY, InvoiceDate DATETIME, CustomerID INT FOREIGN KEY REFERENCES tbl_Customer(CustomerID), SubTotal DECIMAL(18,2), DiscountPercent DECIMAL(5,2), TaxAmount DECIMAL(18,2), GrandTotal DECIMAL(18,2) );

Introduction In the world of small to medium-sized enterprises (SMEs), billing and invoicing remain the backbone of daily operations. While cloud-based SaaS solutions dominate the headlines, many businesses still prefer—or require—a fast, reliable, offline-capable desktop application.