Hi,

 

Please check the samples code.

 

1 - when you use UploadAttachments , you can use the Items collection to get the files . each item has properties and methods to let you access the file information and data.

 

2 - You need use the properties and methods to copy/move or open the stream .

 

# please check the manual start sample

10. Start uploading manually
This sample demonstrates how to start uploading manually after file selection vs automatically.

 

3 - use the properties and methods to get the information.

 

4 - use the ValidateOption.AllowedFileExtensions property.

 

5 - after you uploaded the file , you can move it to anywhere and use any name.

 

Regards,

Terry