how can i upload file to server in asp.net - asp.net

Question

I have 2 pages send.aspx and recive.aspx.
In send.aspx, I have FileUpload and Button that send selected file to recive.aspx page.
In below you can see recive.aspx.cs code in Page_Load
at the end .
How can I send file to this page?
protected void Page_Load(object sender, EventArgs e)
{
string action = Request.Params["action"];
if (action == null)
{
Response.StatusCode = 400;
Response.End();
}
if (action.Equals("upload"))
{
HttpPostedFile file = Request.Files["file"];
if (file != null && file.ContentLength > 0)
{
//string guid = Guid.NewGuid().ToString();
string ext = Path.GetExtension(file.FileName);
//2- Get and check file extension
string[] validExtesions = { ".e", ".jpg", ".gif", ".png", ".rar",
".zip",".3gp",".3gpp",".mp4",".mov",".wmv",".avi", "",".jpeg", ".mp3", ".ogg"};
if (Array.IndexOf(validExtesions, ext.ToLower()) < 0)
{
Response.Write("Invalid file extension!");
Response.End();
}
//3- Get and check file size
long fileSize = file.ContentLength;
fileSize /= 1024;
if (fileSize > 2048000)
{
Response.Write("Fiele size must be < 2GB");
Response.End();
}
//4- Get file name
string fileName = Path.GetFileName(file.FileName);
//5- Check file exist and if (true) generate new name
while (File.Exists(Path.Combine(UploadFolder, fileName)))
fileName = "1" + fileName;
string fname = fileName;
string path = Server.MapPath(Path.Combine(UploadFolder, fname));
file.SaveAs(path);
Response.Write(fname);
Response.End();
}
else
{
Response.StatusCode = 400;
Response.End();
}
}
}