Although we have a new version of SQL Server 2016, multiple file upload facility is still not given as a built-in function and it annoys us when we have multiple RDL files to be uploaded manually. I am currently working on a Reporting Services project and have the same requirement, hence thought to make a simple application to upload multiple files.
If you make a search, you find related codes, written in many ways. I did a study on some of the code published and made a Windows Application for uploading my files. This is how it looks like;
I can select multiple files and upload;
It works fine for me but need to do more test, I will be continuous enhancing and testing it, if you need the same, please use the download link given below.
Link for the Windows Application: https://1drv.ms/u/s!Ahey1yiqH_9AgZwd-FOt5Qg3ej35oQ