Despite the fact that FastReport.Net provides us with a plugin for the report designer to use as a data source for the JSON file, it is not always suitable. This plugin works well with single-level data representing a separate table. In cases where the data has multiple levels of nesting, you will have to try another solution.
For example, using the Newtonsoft.Json library - with its help you can get data from JSON, make a list from them and register it in a report from code.
Let's look at everything with an example. Create a WinForms application. With the help of NuGet Manager, install the Newtonsoft.Json package. In Reference, add a link to the library FastReport.dll.
Suppose we have sales data for managers in stores. All these data are in one file, but in fact they are three different entities: a store, a manager, a sale. This will be our json file for this example:
...