How to Validate Double Value in VB.Net (2026)

This tutorial is all about How to Validate Double Value in VB.Net. With this tutorial you can Validate Double Value in VB.Net easily. So let’s get started:

First is open the Visual Basic, Select File on the menu, then click New and create a new project.

Then a New Project Dialog will appear. You can rename your project, depending on what you like to name it. After that click OK

Design your form like this just like what I’ve shown you below.

Add a Label, Button and Textbox.
Add this following function.

[vbnet]
Function validateDoublesAndCurrency(ByVal stringValue As String) As Boolean
Dim rslt As Boolean = False
Dim value As Double
Dim valueToTest As String = stringValue
TryvalueToTest = Double.Parse(stringValue, Globalization.NumberStyles.Currency)
Catch ex As ExceptionEnd Try

If Double.TryParse(valueToTest, value) Then

rslt = True
Else

rslt = False
End If
Return rslt
End Function

[/vbnet]

<li>Then add this code to the button.<br></li>

[vbnet]
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If validateDoublesAndCurrency(TextBox1.Text) = False Then
MsgBox("Price entered is not valid")
Else
MsgBox("Price is Valid")
End If
End Sub
[/vbnet]

<li>Finally, Click F5 to run.</li>

Output:

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Frequently Asked Questions

How does this VB.NET project work?

Built with VB.NET WinForms (.NET Framework 4.5+) and SQL Server backend. Standard structure: Form designer to code-behind event handlers to ADO.NET data access layer to SQL Server. Login form for auth. Ready to extend for BSIT capstone scope.

What Visual Studio and SQL Server versions does this VB.NET project require?

Most projects use VB.NET WinForms on .NET Framework 4.5+ with SQL Server 2012 Express or higher. To run: install Visual Studio 2019 / 2022 (Community is free) with the ‘Desktop development with .NET’ workload, install SQL Server Express + SSMS, open the .sln file, build, run.

How do I set up the database for this VB.NET project?

Open SQL Server Management Studio (SSMS) and connect to your SQL Server (e.g. localhost\SQLEXPRESS). Right-click Databases, choose Restore Database OR New Database then import the included .sql script. Update the connection string in App.config (or in code-behind Module) with your server name + credentials. Rebuild and run.

Can I use this VB.NET project for a BSIT capstone or thesis?

Yes, VB.NET is one of the most accepted languages by Philippine BSIT panels. Extend it: add role-based access (admin/staff/customer login redirect), Crystal Reports or RDLC reports, dashboards with Chart control, audit log, multi-branch support. Pair with Chapter 1-5 documentation matching your panel’s rubric.

Why am I getting ‘connection error’ or ‘cannot find SQL Server’?

Three common VB.NET issues: (1) Connection error: SQL Server isn’t running. Open SQL Server Configuration Manager and verify SQL Server (SQLEXPRESS) service is started. (2) Wrong server name in connection string. Try .\SQLEXPRESS, (local)\SQLEXPRESS, or your machine name. (3) Login failed: SQL Server is set to ‘Windows-only’ authentication. Switch to Mixed Mode in SSMS Server Properties, Security.

Where can I find more VB.NET projects with source code?

Browse the VB.NET Projects hub for the full library. For C# WinForms alternatives see C# Projects. For ASP.NET web alternatives see ASP.NET Projects. For BSIT capstone idea lists see 150 Best Capstone Project Ideas.