What does “dabei” refer to?

Question

I was reading the sentence

Ich war gerade dabei die Tür abzuschliessen. Da hast du angerufen.

and I worked out that it meant roughly

I was just about to close the door. While doing that, you called me.

I want to ask about the function of the word dabei. I know that dabei can refer to a specific noun (i.e., as it was happening). But what is the specific use of dabei here? Does it refer to anything in the first sentence?

Answer 1

"Dabei" is expressing what the continuous form in English does - As German doesn't have that, we need to express concurrency of events using this (or other) adverbs.

A proper translation to English would be

I was closing the door when you called.

"dabei" is referring to the predicate here.

Answer 2

Dabei is derived from the preposition bei. Here, dabei refers to the following infinitive clause: die Tür abzuschließen.

An alternative wording is:

Ich war beim Abschließen der Tür.

Dafür and dagegen can be used in the same way:

Ich war dafür, die Tür abzuschließen.

I was in favor of locking the door.

Answer 3

In German there are no continuous tenses. In English you can make a difference between

I locked the door.
I was locking the door.

I German both is

Ich habe die Tür abgeschlossen.

When you want to tell that you was locking the door when the phone rang, it is:

Ich habe die Tür abgeschlossen. Da hast du angerufen.

You have two possibilities to translate this into English:

1. I locked the door. Then you called me.
2. I was locking the door when you called me.

If you want to make clear, that it should be #2, you must use some workaround. A very common way is the phrase

Ich war gerade dabei etwas zu tun

This phrase has no exact translation into English, because when you use this phrase in German, you always can use a continuous tense in English.

In our example you can build this sentence:

Ich war gerade dabei die Tür abzuschließen als du mich angerufen hast.

In this sentence the accusative object of anrufen (mich) is optional, and if you want you can use da instead of als, but then the relative clause must be converted into a full clause, which means, that the auxiliary verb hast must move to position 2. And then you get:

Ich war gerade dabei die Tür abzuschliessen. Da hast du angerufen.

Answer 4

You have seen a lot of answers which used many words to actually explain what to be in the process off means.

In other words, this form of dabei sein,

Ich war dabei, x

simply means

I was in the process of x

Here, x is die Tür abzuschließen = locking the door.

Answer 5

Let's not forget the very common usage of "dabei" in constructions like the following (I'm stating the whole thing in English, with the exception of the word "dabei," so that it's absolutely clear to English-speakers):

The U.S. spends billions of dollars each year for welfare. Dabei there are other, much more cost-effective methods of helping people in need.

In such constructions, "dabei" means "and yet, in this context (or 'regard' or 'respect')."