ASP.NET Web Forms modernisation

It runs, and it will keep running for as long as .NET Framework does, which is tied to the Windows version it ships with. Nothing is switching it off on a date.

What it can't do is move. There is no Web Forms on modern .NET. New libraries don't target it, new developers haven't learned it, and every year the gap between it and the rest of your systems widens. The server it runs on has a date, too: Windows Server 2016 support ends in January 2027.

So a Web Forms application isn't an emergency. It's a migration that gets more expensive each year it waits.

Pages with the logic in the code-behind. A Web Forms application from its era typically has the business rules in the page event handlers, a data layer that may be shared or may be copied into each page, user controls that grew into small applications of their own, and a session that holds far more than it should. Reports, exports and scheduled jobs often hang off the same project.

The valuable part is the rules and the data model, as with any legacy system. The pages themselves are the part that has to be rebuilt, and the point of the staged approach is to rebuild them without stopping the business.

1. Map the application. The assessment lists every page, control, data access path and integration, and sorts the shared code into what can be upgraded and what has to stay with the old pages.
2. Upgrade the shared code first. Business logic and data access move to a library both applications can use, so the rules exist once. Entity Framework 6 usually moves to EF Core here.
3. Stand up the new application behind a proxy. An ASP.NET Core site sits in front of the old one, with a reverse proxy passing through any page it doesn't yet own. Microsoft's adapters share authentication and session between the two, so users see one application.
4. Move pages in order of value. Each page is rebuilt (Razor Pages, MVC or Blazor, chosen once for the whole application), tested against a copy, run in staging alongside the old page on the same data, checked by the people who use it, then switched. The old page stays reachable until the new one has proven itself.
5. Retire Web Forms when the last page that matters has moved.

Each stage has its own fixed price, and each ends with working software.

One choice, made once, for the whole application. Razor Pages is the closest in shape to Web Forms (a page, its code behind it) and the easiest for a team that knows Web Forms to read. MVC suits applications that already separate their logic well. Blazor suits screens with a lot of interaction, and can replace controls within a Web Forms page during the migration. The assessment recommends one from what's in your application and how your team works.

Usually SQL Server, and it stays where it is. Old and new applications share the same database throughout the migration, so there's no data move and no day when two versions of the truth exist. Where the data access layer changes, the new queries are tested on a copy, then in staging against the live schema, before anything connects to live.

The assessment is from £395 + VAT, sized on a free one-hour consultation, with an exact price before you commit. For a Web Forms application it counts the pages and controls, sorts the shared code, and prices the proxy setup and the first pages as fixed numbers. What drives the price and the payment terms each have a page.

The big-bang rewrite, first. A Web Forms replacement built in full before going live is the project that stalls. The proxy approach exists so that every page ships on its own.

The second risk is the server. Windows Server 2016 goes out of support in January 2027, and a Web Forms application on it goes with it. Moving the old site to a supported server is a stage that can happen before, during or instead of the migration, and the assessment says which.

Shared code first, then a proxy, then pages by value. Marc Allington has built on .NET Framework for years and builds on modern .NET now, so both ends of the migration are familiar. Everything we build runs on open, widely used technology, in your own accounts, with full source code and ownership transferring to you on final payment. The wider .NET Framework picture has its own page.