Did you know that DotVVM can be used to incrementally modernize old ASP.NET Web Forms applications and lift them to .NET Core? It is much easier than doing a full rewrite, and the application can be deployed at any time during the entire process.
- Install DotVVM NuGet package in your Web Forms site
- Create a DotVVM master page using the same CSS
- Start converting ASPX pages to DotHTML syntax, one at a time
- When all the Web Forms pages are gone, change your CSPROJ to use .NET Core