Still not much to go on.  Remove the base cover and disconnect the battery.  Hold the power button for 30 sec and reconnect it.

Then restart - if the battery is still absent, it's dead - you'll need to replace it with a new one.

XPS 15 , windows 10 the latest update 

What model computer and OS? Instead of posting a picture that we can't see until it's approved by mods, explain it in your post.

The battery isn’t dead because it say it is connected. Just not charging. It also charged somehow last night. 

It says “alert! The ac power adapter wattage and type cannot be determined. The battery may not charge. The system will adjust the performance to match the power available.”

I do not understand what it wrong and what has caused this. No one has recommended buying a new battery. Is this a troll

The problem was your initial post, which is that the battery isn't recognized.

This is a different issue.  If the AC adapter is not recognized, the battery will not charge, but the system should recognize it.  If the battery IS recognized, but the adapter isn't:

1. Try a new (or another) Dell OEM AC adapter.  If it works, the problem is a faulty adapter.  If another adapter doesn't solve the problem,

2.  Change the DC power jack in the system.  If you need a part reference, post the model number - not just XPS 15, but XPS 9550, 9650, 9750, etc.

3.  If the adapter and jack change don't get the adapter recognized, it's the charge circuit that's bad and the system board will need to be replaced.

This solution did not work for me.  I bought a new battery.  The battery charges completely. But, the battery does not get recognized - as I disconnect the power cable from the computer with the fully charged new battery in there, the computer behaves as if there is no power and shuts off.

I bought a new battery off amazon since Dell no longer sells the 9560 batteries to replace. Now my bios says the battery isn't identifiable and will not charge.