Skip to content
Switch branches/tags

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time

WebWinFormsInteraction - An approach to use parts of your legacy app in a modern web app

This demo was made for an article in the Windows Developer magazine which was printed in November 2018.

The article describes an approach to migrate a huge legacy pc app to a modern web app step-by-step. To release a.s.a.p., the usage of old functionality in the new app might be a good option. Usually it's not possible to migrate code from decades within a year.

In this Demo the web client and the locally installed WinForms app communicate through a SignalR Hub which is also installed on the users computer.


Getting started

Clone this repo

  • Start Command Line Console in the directory you want to have the code
  • run git clone

Install and run Webserver for Angular App

  • Navigate (cmd) to the folder 'WebFrontend'
  • run code . to open the folder in VS Code and return to the console
  • run npm install to restore the node_modules (npm packages)
  • run ng serve

Install and run API, SignalR Hub and WinForms App

  • Navigate to the folder 'DotNetParts' and open DotNetParts.sln with Visual Studio
  • Run App by Pressing F5. SignalR Hub (Console App), WebAPI (AspNet .NetCore) and WinForms App will be started


  • Start "Old App" from the starter form.
  • Open the Web App by klicking the button top left.
  • Choose and change person in the "New Web App" and observe the synchronization in the old App.
  • Press "Edit" on the person -> the old App changes to Edit Mode and appear in front.
  • Save... Edit... Change person... close WinForms App (not the Starter Form) -> Web App logs out. Re-open old App -> Web is awailable again...
  • Close Old App window and observe web logout
  • Open a new Old App window and get logged-in on the web app again.
  • ...


In the sequence they usually grow...

  • Old WinForms App "DotNetParts.WinFormsFrontend": Old App dispatching relevant actions to the SignalR Hub and executing actions requested by the new client (notified by the hub).
  • WebAPI "DotNetPartsPersonApi": REST API shared by old and new client. In this case the data is just held in memory.
  • SignalR Hub "DotNetParts.InteractionHub": Communication centre for all frontends old and new installed on the client (with the old app). It broadcasts acitons to "the others" (other subscribed clients).
  • New Web App "WebFrontend": Angular Frontend which requests the aciton "edit person" from the old app as an example of using old code in the web.

It is...

  • an inspiration for developers having the challenge to migrate huge legacy apps to the web.
  • an example how old technologies and web can interact.

It isn't...

  • a general recipe for migrating old apps.
  • a tutorial how to secure a production app.

Check, design, protoype and challenge your situation in your environment! My article in the Windows Developer magazine (December 2018) might give your additional useful thoughts to this topic.


Demos from Article in Windows Developer




No releases published


No packages published