How to assign value from session upload file into upload posted file again

Question

i am trying to save uploaded file after some big process.

i am saving uploaded file in session to retain the file upload data.

i.e : uploaded file will be saving into session variable. after saving to session upload file will be cleared. but, the upload file name will saved into session.

when i am saving the below code i used. ut, i am getting error.

FileUpload FileUpload1 = null;

FileUpload1 = (FileUpload)Session["FileUpload1"]; //

//Save file with re-named file.

            SaveFile(FileUpload1, Path);
``````aspx-csharp
 private void SaveFile(FileUpload fileupload, string path)
        {
            fileupload.PostedFile.SaveAs(path);
            const int numberOfRetries = 10;
            const int delayOnRetry = 1000;

            for (int i = 1; i <= numberOfRetries; ++i)
            {
                try
                {
                    fileupload.PostedFile.SaveAs(path);
                    break;
                }
                catch (IOException e) when (i <= numberOfRetries)
                {
                    Thread.Sleep(delayOnRetry);
                }
            }
            fileupload.Dispose();
        }

how to save the session value file into database...?

Answer 1

Hi @Gani_tpt,

If you insist on using session, you can refer to the following example.

One thing to note is that in order to prevent users from forgetting to click the "Upload" button, I have added code in the example to upload the file using the FileUpload control without clicking the "Upload" button.

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
 <script type="text/javascript">
     function UploadFile(fileUpload) {
         if (fileUpload.value != '') {
             $("[id*=gvCustomers]").find("[id*=Button1]").click();
         }
     }
 </script>

 <asp:FileUpload ID="fuUpload" runat="server" />
 <asp:Label ID="ImageErrorLabel" runat="server" />
 <asp:Button ID="Button1" Text="Upload" OnClick="Upload" runat="server" Style="display: none" />

protected void Page_Load(object sender, EventArgs e)
{
    Control control = null;
    DropDownList DropDownList1 = null;
    if (!this.IsPostBack)
    {
        this.BindGrid();
        if (gvCustomers.FooterRow != null)
        {
            control = gvCustomers.FooterRow;
            DropDownList1 = (control.FindControl("ddlCustomers") as DropDownList);
        }
        else
        {
            control = gvCustomers.Controls[0].Controls[0];
            DropDownList1 = (control.FindControl("ddlCustomer") as DropDownList);
        }
        FileUpload fuUpload = (FileUpload)control.FindControl("fuUpload");
        fuUpload.Attributes["onchange"] = "UploadFile(this)";
        List<Item> items = new List<Item>();
        items.Add(new Item() { Value = "1", Text = "USA" });
        items.Add(new Item() { Value = "2", Text = "UK" });
        items.Add(new Item() { Value = "3", Text = "AUS" });
        items.Add(new Item() { Value = "4", Text = "OTHERS" });
        DropDownList1.DataSource = items;
        DropDownList1.DataTextField = "Text";
        DropDownList1.DataValueField = "Value";
        DropDownList1.DataBind();
        DropDownList1.Items.Insert(0, new ListItem("--Select --", "0"));
    }
    if (this.IsPostBack)
    {
        if (gvCustomers.FooterRow != null)
        {
            control = gvCustomers.FooterRow;
        }
        else
        {
            control = gvCustomers.Controls[0].Controls[0];
        }
        Label label = (control.FindControl("ImageErrorLabel") as Label);
        FileUpload fuUpload = (FileUpload)control.FindControl("fuUpload");
        if (Session["FileUpload1"] == null && fuUpload.HasFile)
        {
            Session["FileUpload1"] = fuUpload.PostedFile;
            label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
        }
        else if (Session["FileUpload1"] != null && (!fuUpload.HasFile))
        {
            HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
            label.Text = Path.GetFileName(file.FileName);
        }
        else if (fuUpload.HasFile)
        {
            Session["FileUpload1"] = fuUpload.PostedFile;
            label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
        }
    }
}
protected void Upload(object sender, EventArgs e)
{
    Control control = null;
    if (gvCustomers.FooterRow != null)
    {
        control = gvCustomers.FooterRow;
    }
    else
    {
        control = gvCustomers.Controls[0].Controls[0];
    }
    Label label = (control.FindControl("ImageErrorLabel") as Label);
    FileUpload fuUpload = (FileUpload)control.FindControl("fuUpload");
    if (Session["FileUpload1"] == null && fuUpload.HasFile)
    {
        Session["FileUpload1"] = fuUpload.PostedFile;
        label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
        HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
        SaveFile(file);
    }
    else if (Session["FileUpload1"] != null && (!fuUpload.HasFile))
    {
        HttpPostedFile file = (HttpPostedFile)Session["FileUpload1"];
        label.Text = Path.GetFileName(file.FileName);
        SaveFile(file);
    }
    else if (fuUpload.HasFile)
    {
        Session["FileUpload1"] = fuUpload.PostedFile;
        label.Text = Path.GetFileName(fuUpload.PostedFile.FileName);
        SaveFile(fuUpload.PostedFile);
    }
}
private void SaveFile(HttpPostedFile file)
{
    string fname = Path.GetFileName(file.FileName);
    file.SaveAs(Server.MapPath("~/images/" + fname));
}

Best regards,
Lan Huang

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Answer 2

you can not save the PostedFile object in session as its disposed on request end. you need to read the file stream into a byte buffer (array), and save the buffer.