Activating feature from another feature

Question

Can we activate a feature by adding two features to the solution and activating the one of the feature from another features FeatureInstalled Event?

I am trying to activate the feature of the current solution when the solution is deployed?

And all I am asking is about a Site Collection Feature.

Answer 1

I'm almost 100% sure it's possible, but something tells me there's a better way of doing this depending on your use case and I think it's called Feature Stapling. I think of it as a declarative way to attach features to site definitions (yea, not really sticking it to other features but rather to site definitions, so that when a site gets created with said (or any) site definition, the feature is automatically activated).

If you'd rather only activate your Feature B when Feature A gets activated, I'd go ahead and just do it from Code.

if(feature==null)//if feature is not activated
{
   site.Features.Add(featureId);//activate feature
}

and the reverse:

if(feature!=null)//if feature is activated
{
    site.Features.Remove(feature.DefinitionId);//deactivate feature
}

EDIT: For Feature Stapling, keep this in mind:

The scope of the feature that does the stapling must be higher than the features being stapled. For example, a feature at the site collection scope can staple only features at site-level scope. So, you can fine tune the your feature scope accordingly

A nice feature stapling walkthrough

Answer 2

Automatically activating another feature inside the FeatureActivated handler for some initial feature works fine for Farm solutions. For Sandbox solutions it's a no go though - if you need that you may have to do it using JavaScript (it's not that hard).

Answer 3

This will depend on the order in which features are installed. If the feature you want to activate programmatically in other feature's installed event is already installed then it can be activated otherwise not.