Show HN: GPT helped me rebuild a .NET app in 30 mins what took 3 weeks in MFC

3 CodeAndExile 1 8/4/2025, 2:10:39 AM

I've never used .NET, know nothing about .NET or vb, or anything outside vc++ & MFC.

Recently I gave GPT a try, guiding it step by step, and asking it to help me rebuild a tool I originally wrote in MFC. To my surprise, it worked: a full Excel-to-PDF automation app, done in 30 minutes; including a small algorithm I thought would be too tricky for AI to handle.

I didn't understand even a single line of the code, I just kept asking, copying, and running.

It felt amazing… but also terrifying.If AI can do this now, what happens 5 years from now?

Here's a 5-min video I made showing the full process with real code running (no cuts, just sped up):

https://youtu.be/-mf_yOhOCfs

Not selling anything. Just sharing what shocked me.

Comments (1)

CodeAndExile · 2h ago

I still have no idea how .NET syntax works, but somehow the app runs perfectly. Happy to answer anything if folks are curious. I have both versions of the source code (the original MFC one and the GPT-generated one), in case anyone's interested.

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Show HN: GPT helped me rebuild a .NET app in 30 mins what took 3 weeks in MFC

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