How to pass the nest json object parameters to api with httpclient ?

I need to pass a complex json object as parameters to api with httpclient, the json format like below:

and the problem is many of these objects are dynamic, for example, the "guid1" under photos will be more than one and the name will be difference:
guid1:{}, guid2{}, guid3{}...

also, the children under inspection_values are dynamic, it will be more than one

so how can I do that? thanks!