Thought it might save people a lot of trouble if they knew a bad solution to avoid. I follow up with something that seems to be working.
VS2022. .netCore 8.0. Already had a WebAPI project to which I wanted to add an rdlc report.
Had the same issue, and worse. Not sure how, someone at work claimed he was able to create a new rdlc but the steps he gave never worked on anyone elses’ machine. So we just copy pasted the rdlc file he created and tried working on it from there.
The DataSet/DataSource dropdowns wouldn’t work consistently. Wouldn’t work at all unless our classes had primitive data types only and they were changed to interfaces with implementations. If you edited a class associated with a dataset that had been working, it would stop working.
I started a .netcore windows form app, and all the usual rdlc functionality started working. Much the same seems true for a standalone reporting project. I wrapped up teh classes I needed from my api into a Class LIbrary and imporfted into the reports project. So far so good. I wrap up my Data Access Layer and should be able to use that to generate the report. Then import that as a Project Reference
Not sure if this is is related, but Microsoft Reporting Services doesn’t seem to be compatible with .net 8.0. Was thinking of sorting that out, but since I have something workable, I’m avoiding it.