The RadUpload allows the files to be uploaded automatically after the user selects them from the browse dialog window. Which means that the user won't have to click the Upload button to start the process. To enable the Automatic Upload feature you can set the IsAutomaticUpload property of the RadUpload to True (its default value is False).

CopyXAML

<telerik:RadUpload IsAutomaticUpload="True" />

CopyC#

RadUpload radUpload = new RadUpload();
radUpload.IsAutomaticUpload = true;

CopyVB.NET

Dim radUpload As New RadUpload()
radUpload.IsAutomaticUpload = True