Upload and download files in ASP. NET

// Check that the uploaded file is not empty
If (File1.PostedFile! = Null)
{
String nam = File1.PostedFile. FileName;
// Obtain the index of the last "." In the file name (including the path)
Int I = nam. LastIndexOf (".");
// Get the file extension
String newext = nam. Substring (I );
// Here, I automatically name the File Based on the date and file size to ensure that the file name is not repeated
DateTime now = DateTime. Now;
String newname = now. DayOfYear. ToString () + File1.PostedFile. ContentLength. ToString ();
// Save the file to the directory you want. This is the upload directory under the IIS root directory. You can change it.
// Note: Here I use Server. MapPath () to retrieve the absolute directory of the current file. In asp.net, "" must be replaced ""
File1.PostedFile. SaveAs (Server. MapPath ("upload" + newname + newext ));
This. HyperLink1.NavigateUrl = "upload" + newname + newext;
// Obtain the relevant attributes of the file: file name, file type, and file size.
// Fname. Text = File1.PostedFile. FileName;
// Fenc. Text = File1.PostedFile. ContentType;
// Fsize. Text = File1.PostedFile. ContentLength. ToString ();
}