We would like to let you know that the reported issue has occurs due to wrong extension type given in the controller page. It should be ‘.txt’ for text documents and save function will not be executed, in case of wrong extension type.
Function FileUpload() As ActionResult
Dim myModel As New UploadBoxModel
myModel.AutoUpload = True
myModel.AllowMultipleFiles = True
myModel.ExtensionsAllow = "txt"
ViewData("upload") = myModel
Please refer the attached sample for your reference.