You can achieve programmatic upload by using the different methods exposed by the RadUpload control. Here is a list of them:
CancelUpload() - cancels the current upload. When the upload gets canceled the UploadCanceled event is raised.
PauseUpload() - pauses the current upload. When the upload gets paused the UploadPaused event is raised.
ResumeUpload() - resumes the paused upload. When the upload gets resumed the UploadResumed event is raised.
ShowFileDialog() - opens the browse dialog window.
StartUpload() - starts the upload. When the upload gets started the UploadStarted event is raised.
To learn more about the events of the RadUpload read here.
You can use the Items.Count property to see if any files have been selected for upload, before starting it.