Vb.net Billing Software Source Code 【TOP — 2025】

Let's explore the most critical parts of the source code.

"The lack of a layered architecture makes the application brittle. For example, if the database schema changes, modifications are required directly in the UI event handlers (e.g., BtnSave_Click), violating the Open/Closed Principle."

When you download or build "VB.NET billing software source code," the Visual Studio solution will look like this:

-- Create Database
CREATE DATABASE BillingSystem;
GO
USE BillingSystem;
GO
-- Products Table
CREATE TABLE Products (
ProductID INT PRIMARY KEY IDENTITY(1,1),
ProductCode NVARCHAR(50) UNIQUE NOT NULL,
ProductName NVARCHAR(100) NOT NULL,
Category NVARCHAR(50),
UnitPrice DECIMAL(10,2) NOT NULL,
StockQuantity INT NOT NULL DEFAULT 0,
GSTPercentage DECIMAL(5,2) DEFAULT 0,
CreatedDate DATETIME DEFAULT GETDATE()
); vb.net billing software source code
-- Customers Table
CREATE TABLE Customers (
CustomerID INT PRIMARY KEY IDENTITY(1,1),
CustomerName NVARCHAR(100) NOT NULL,
PhoneNumber NVARCHAR(15),
Email NVARCHAR(100),
Address NVARCHAR(255),
CreatedDate DATETIME DEFAULT GETDATE()
);
-- Invoices Table
CREATE TABLE Invoices (
InvoiceID INT PRIMARY KEY IDENTITY(1,1),
InvoiceNumber NVARCHAR(20) UNIQUE NOT NULL,
CustomerID INT FOREIGN KEY REFERENCES Customers(CustomerID),
InvoiceDate DATETIME DEFAULT GETDATE(),
SubTotal DECIMAL(10,2),
GSTAmount DECIMAL(10,2),
TotalAmount DECIMAL(10,2),
PaymentMethod NVARCHAR(50),
Status NVARCHAR(20) DEFAULT 'Pending'
);
-- Invoice Items Table
CREATE TABLE InvoiceItems (
ItemID INT PRIMARY KEY IDENTITY(1,1),
InvoiceID INT FOREIGN KEY REFERENCES Invoices(InvoiceID),
ProductID INT FOREIGN KEY REFERENCES Products(ProductID),
Quantity INT NOT NULL,
UnitPrice DECIMAL(10,2),
TotalPrice DECIMAL(10,2),
GSTAmount DECIMAL(10,2)
);

Private Sub btnAddItem_Click(sender As Object, e As EventArgs) Handles btnAddItem.Click
    ' Assume txtProductCode, txtQuantity, dgvCart are controls
    Dim productCode As String = txtProductCode.Text.Trim
    Dim qty As Integer = Integer.Parse(txtQuantity.Text)
' Fetch product from DB
Dim cmd As New SqlCommand("SELECT ProductID, ProductName, UnitPrice, GST_Percent, StockQuantity FROM tbl_Product WHERE ProductCode=@code", con)
cmd.Parameters.AddWithValue("@code", productCode)
Dim da As New SqlDataAdapter(cmd)
Dim dt As New DataTable
da.Fill(dt)
If dt.Rows.Count = 0 Then
    MessageBox.Show("Product not found")
    Return
End If
Dim row As DataRow = dt.Rows(0)
If qty > Convert.ToInt32(row("StockQuantity")) Then
    MessageBox.Show("Insufficient stock")
    Return
End If
' Add to DataGridView (cart)
dgvCart.Rows.Add(
    row("ProductID"),
    row("ProductName"),
    qty,
    row("UnitPrice"),
    row("GST_Percent"),
    qty * Convert.ToDecimal(row("UnitPrice"))
)
' Recalculate totals
RecalculateCartTotal()

End Sub

Are you tired of the monthly subscription fees of QuickBooks? Frustrated that your current invoicing software doesn’t quite fit your specific business workflow?

Every business owner reaches a breaking point where they think, "I could build this myself." If you are a developer or a tech-savvy entrepreneur, diving into VB.NET billing software source code might be the best business decision you make this year. Let's explore the most critical parts of the source code

In this post, we’re going to explore why legacy tech isn’t dead, where to find the right source code, and how customizing your own billing engine can save you thousands of dollars.

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.

VB.NET (Visual Basic .NET), combined with the robust .NET Framework, remains a powerful, underrated tool for building exactly this type of software. If you have searched for "VB.NET billing software source code," you are likely looking for a foundation to build, customize, or deploy a complete billing system.

This article will explore what makes VB.NET ideal for billing systems, the core modules you need, a breakdown of source code architecture, database design, and how to extend open-source projects to fit real-world business needs. "The lack of a layered architecture makes the

Imports System.Windows.Forms
Public Class BillingSoftware
    Private Sub btnAddItem_Click(sender As Object, e As EventArgs) Handles btnAddItem.Click
        If txtItemName.Text <> "" AndAlso txtQuantity.Text <> "" AndAlso txtPrice.Text <> "" Then
            ListView1.Items.Add(txtItemName.Text)
            Dim lvItem As ListViewItem = ListView1.Items(ListView1.Items.Count - 1)
            lvItem.SubItems.Add(txtQuantity.Text)
            lvItem.SubItems.Add(txtPrice.Text)
            CalculateTotal()
            txtItemName.Clear()
            txtQuantity.Clear()
            txtPrice.Clear()
            txtItemName.Focus()
        Else
            MessageBox.Show("Please fill in all fields.")
        End If
    End Sub
Private Sub CalculateTotal()
        Dim subtotal As Double = 0
        For Each item As ListViewItem In ListView1.Items
            subtotal += Convert.ToDouble(item.SubItems(2).Text) * Convert.ToInt32(item.SubItems(1).Text)
        Next
        lblSubtotal.Text = "Subtotal: $" & subtotal.ToString("F2")
        Dim tax As Double = subtotal * 0.08
        lblTax.Text = "Tax (8%): $" & tax.ToString("F2")
        Dim total As Double = subtotal + tax
        lblTotal.Text = "Total: $" & total.ToString("F2")
    End Sub
Private Sub ListView1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListView1.SelectedIndexChanged
        ' You can add functionality here for editing or removing items
    End Sub
Private Sub BillingSoftware_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        ListView1.View = View.Details
        ListView1.GridLines = True
        ListView1.FullRowSelect = True
        ListView1.Columns.Add("Item", 150)
        ListView1.Columns.Add("Quantity", 75)
        ListView1.Columns.Add("Price", 75)
    End Sub
End Class