[Packaging] automatic installer for applications!

[CypherPotato]

We know how frustrating it is for our client or friend who is going to test our application to open it for the first time and come across this technical, verbose, and unfriendly message indicating that their friend does not have the runtime installed:

This message displays a lot of information, much of which is often irrelevant to the end user. If it's someone with a bit more knowledge, they will see and know that they need to download something. The message takes you to the download page for the correct runtime, and it does this well, for both console and Windows Forms applications. But, the user has to go through the trouble of reading the message, downloading the runtime, installing it, and then opening the application again. For us developers, this is a common day-to-day task, but for the end user, this is inconvenient, which leads us to one of the options:

• Build a self-contained, single-file application: this option forces us to distribute a large executable, often over 70mb if your application makes extensive use of packages and references. Furthermore, the application's startup time also becomes a bit longer.
• Go Native AOT: it is not compatible with most existing projects or requires a huge sacrifice to become stable enough for a production application, and does not support cross-compilation.
• Instruct the user to download .NET: this option puts us in a conversation that was not supposed to happen with the user.

We are talking about convenience, both for the developer and the end-user. This solution is aimed at the portability of .NET applications, improving their distribution and removing the need to resort to a third-party installer.

And what if the message that the system does not have the runtime was actually an installer for the non-installed runtime?

My idea is simple: discard the technical information and automatically install the required.NET runtime in silent mode on the person machine opening the .NET application. Show a visible progress to the user so they don't think the application is taking too long to open, maybe a confirmation, and as soon as it's installed, start the downloaded application.

For older .NET Framework applications, this behavior already occurs on Windows:

It could have a property in MSBuild to enable or disable this feature if it's not desired by the application developer. This feature would greatly simplify the distribution of applications.

[huoyaoyuan]

For Windows desktop application, a message dialog with a download link is already displayed: #78087

[CypherPotato]

It does. And I already mentioned that.

But that's the same problem with console applications: you must open the link, download the runtime, follow the installation wizard then open your application again. We could solve all these steps with one click.

[huoyaoyuan]

The complexity of the executable file is a problem. In .NET Framework, the installation logic is handled by Windows system. In .NET Core, all of these need to be carried within the executable file. Network related code is much more complex than displaying a message only.