Your father showed you the whole kingdom, did he?

[lagoo]

I think the correct form might be " Your father showed you the whole kingdom, didn't he?" as per what I've learned from the school books.
Is it wrong to use "did he" instead of "didn't he"?

link of the source https://getyarn.io/yarn-clip/bf35959f-61ff-4707-bb4e-7ca0226a7090

 

[lagoo]

The tag questions would be like this:
1) You can sing, can't you?
2) She is coming at 8 o'clock, isn't she?

So why are they different to my question sentence?

 

[Matthew Wai]

I think the difference lies in the word 'so' used in the original sentence.

 

[tedmc]

That is called a "same-way" question tag, with both the statement and question tags in the positive.
It is used when the speaker expresses surprise, interest, anger, concern or any such sudden feeling.

http://novaenglishcampus.blogspot.my/2010/05/same-way-question-tags.html