VB.NET to C#: A Survival Guide for Legacy WebForms Developers

It is 2025. You are staring at a `Dim x As Integer` statement. You look at StackOverflow, and 99% of the answers are in C#. You feel like a COBOL developer in the 90s.

We love VB.NET here at Great Meets. It built the internet. But the reality is that the .NET ecosystem has moved on. If you want to use modern libraries (Blazor, MAUI) or just get a new job, you need to speak C#.

The good news? It is the exact same framework underneath. Here is how to survive the switch without rewriting your entire application.

1. The Mental Shift: "End Sub" vs. "}"

VB.NET is designed to be read like English. C# is designed to be read like Math. The hardest part isn't the code; it's the anxiety of the Semicolon.

2. The "Case Sensitivity" Monster

In VB, `myVariable` and `MyVariable` are the same thing. In C#, they are two different people who hate each other.

3. The WebForms Trap: Event Handlers

This is where WebForms developers get stuck. VB.NET uses the magic Handles keyword at the end of a method.

VB.NET:

Protected Sub Button1_Click(...) Handles Button1.Click

C# does not have a `Handles` keyword. You must wire it up in the ASPX Markup or the Designer.

C# (In the .aspx file):

<asp:Button ID="Button1" OnClick="Button1_Click" ... />

If you copy-paste VB code to C# and forget to add the `OnClick` attribute in the HTML, your button will do nothing. This silent failure drives developers crazy.

4. The "My" Namespace

VB gave us shortcuts like `My.Computer.FileSystem` or `My.User`. C# does not hold your hand like that.

• My.Computer.FileSystem.WriteAllText ? System.IO.File.WriteAllText
• IsNumeric(x) ? int.TryParse(x, out int result)

5. How to Port Safely (Strategy)

Do not try to rewrite the whole app at once. You will fail. Instead, use the "Hybrid Strategy."

1. Keep the VB Project: Leave your existing `.vb` files alone.
2. Add a C# Class Library: Create a new project in your solution (e.g., `GreatMeets.Core.CS`).
3. Migrate Logic First: Move business logic (Classes, Data Access) to C# one file at a time.
4. Reference it: Your VB.NET WebForms pages can call C# libraries perfectly fine.

Conclusion: Use the AI

In 2015, porting code was manual labor. In 2025, we have ChatGPT.

Don't waste time typing syntax. Copy your VB function, paste it into ChatGPT, and say: "Convert this to C#. Use modern syntax." It handles the semicolons so you can focus on the architecture.