Vbnet+billing+software+source+code May 2026

' Check if already in cart Dim existingRow() As DataRow = cartTable.Select($"ProductID = productID") If existingRow.Length > 0 Then existingRow(0)("Quantity") += 1 Dim qty As Integer = Convert.ToInt32(existingRow(0)("Quantity")) Dim totalBeforeGST As Decimal = qty * price Dim gstAmt As Decimal = totalBeforeGST * (gstPercent / 100) existingRow(0)("GST_Amount") = gstAmt existingRow(0)("Total") = totalBeforeGST + gstAmt Else Dim gstAmt As Decimal = price * (gstPercent / 100) Dim totalWithGST As Decimal = price + gstAmt cartTable.Rows.Add(productID, pName, 1, price, gstPercent, gstAmt, totalWithGST) End If CalculateTotals() txtProductCode.Clear() txtProductCode.Focus() Else MessageBox.Show("Product not found!") End If End If End Sub

MessageBox.Show($"Invoice Generated: invoiceNo") PrintInvoice(invoiceNo) ' Clear cart and reset cartTable.Clear() CalculateTotals() End Sub End Class Add a PrintDocument control and its PrintPage event. vbnet+billing+software+source+code

Private Sub txtProductCode_KeyDown(sender As Object, e As KeyEventArgs) Handles txtProductCode.KeyDown If e.KeyCode = Keys.Enter Then Dim productCode As String = txtProductCode.Text.Trim() Dim query As String = $"SELECT ProductID, ProductName, UnitPrice, StockQuantity, GST_Percent FROM tbl_Products WHERE ProductCode='productCode'" Dim dt As DataTable = ExecuteQuery(query) ' Check if already in cart Dim existingRow()

Private WithEvents pd As New Printing.PrintDocument Private invoiceContent As String Private Sub PrintInvoice(ByVal invNo As String) ' Build invoice text Dim sb As New System.Text.StringBuilder() sb.AppendLine(" MY BILLING SOFTWARE ") sb.AppendLine("--------------------------") sb.AppendLine($"Invoice No: invNo") sb.AppendLine($"Date: DateTime.Now") sb.AppendLine("--------------------------") sb.AppendLine("Item Qty Price Total") For Each row As DataRow In cartTable.Rows sb.AppendLine($"row("ProductName") row("Quantity") row("Price") row("Total")") Next sb.AppendLine("--------------------------") sb.AppendLine($"Grand Total: lblGrandTotal.Text") sb.AppendLine("--------------------------") sb.AppendLine(" Thank you! ") vbnet+billing+software+source+code

If dt.Rows.Count > 0 Then Dim productID As Integer = dt.Rows(0)("ProductID") Dim pName As String = dt.Rows(0)("ProductName") Dim price As Decimal = Convert.ToDecimal(dt.Rows(0)("UnitPrice")) Dim gstPercent As Integer = Convert.ToInt32(dt.Rows(0)("GST_Percent"))

invoiceContent = sb.ToString() pd.Print() End Sub