Add possibility to run "Launching elevated engine process" before the plan phase

[softlion]

Feature request : Launching elevated engine process

• Describe the scenario and benefits that the feature supports.

Providing an elevated command prompt before asking user informations (like a custom web user and password) benefits the user: if he does not have windows admin access, he will know immediatly and won't continue instead of being frustrated (he fills one or more form, and finally is blocked).

• Describe how you're accomplishing the feature today (if possible).

I don't use the planning phase. If a feature should not be installed, i use the ExecutePackageBegin event with "Ignore" in the return value. If user input is required, i hold the return from this event using an AutoResetEvent which is signaled once the UI tells the engine can continue.

• Describe what you'd like the new feature to do.

A simple option in bundle.wxs to start the elevated process on launch.

[softlion]

I just found this blog article which explains how to do that in an insecure way: by replacing the Burn manifest: https://www.firegiant.com/blog/2016/1/20/wix-v3.10.2-released/

As this is not secure, a better way would be to fix the Engine.Elevate method and the mba Elevate event so they work correctly in all situations: they currently won't work in a windows 10 administrator account where uac is disabled: the process is still not runned as administrator and can not write in HKLM for example.

[softlion]

Found in another blog that Engine.Elevate does not elevate the current process (ie: the custom installer code). So all of this is pointless. Just use Engine.Elevate() as it is currently implemented ...