[Solved] Downloading multiple files as Zip File return empty Zip File in ASP.Net

Hi,

This is my table on MySQL database.

+----+----------------------------------+---------------------------------+----------------------------------+---------------------------------+
| ID | xls                              | img                             | ppt                              | pdf                             |
+----+----------------------------------+---------------------------------+----------------------------------+---------------------------------+
|  1 | c:\inetpub\wwwroot\xls\test.xlsx | c:\inetpub\wwwroot\img\test.jpg | c:\inetpub\wwwroot\ppt\test.pptx | c:\inetpub\wwwroot\pdf\test.pdf |
+----+----------------------------------+---------------------------------+----------------------------------+---------------------------------+

On gridview using asp net and c# I have set

<asp:TemplateField
    ItemStyle-HorizontalAlign="Center"
    HeaderText="Download">
    <ItemTemplate>
        <asp:ImageButton ID="img" runat="server"
            ImageUrl="/aspnet/img/zip.gif" OnClick="img_Click" />
    </ItemTemplate>
</asp:TemplateField> 

I need download a single zip file that joins the individual four files.

I have tried this tutorial but the zip file is empty.

If change this part of code from

string img = reader["img"].ToString();
string ppt = reader["ppt"].ToString();
string xls = reader["xls"].ToString();
string pdf = reader["pdf"].ToString(); 

to

string img = @"c:\inetpub\wwwroot\img\test.jpg";
string ppt = @"c:\inetpub\wwwroot\ppt\test.pptx";
string xls = @"c:\inetpub\wwwroot\xls\test.xlsx";
string pdf = @"c:\inetpub\wwwroot\pdf\test.pdf";

the files are downloaded correctly.

My code below

Please help me do it.

using (MySqlConnection cn = new MySqlConnection(ConfigurationManager.ConnectionStrings["cn"].ConnectionString))
{
    using (MySqlCommand cmd =
        new MySqlCommand("SP_zip", cn))
    {
        cmd.Connection.Open();
        cmd.CommandType = CommandType.StoredProcedure;

        MySqlDataReader reader = cmd.ExecuteReader();

        while (reader.Read())
        {                  
            using (ZipFile zip = new ZipFile())
            {
                zip.AlternateEncodingUsage = ZipOption.AsNecessary;
                zip.AddDirectoryByName("Files");

                string img = reader["img"].ToString();
                string ppt = reader["ppt"].ToString();
                string xls = reader["xls"].ToString();
                string pdf = reader["pdf"].ToString();

                if (img != string.Empty)
                {
                    zip.AddFile(img, "Files");
                }
                if (ppt != string.Empty)
                {
                    zip.AddFile(ppt, "Files");
                }
                if (xls != string.Empty)
                {
                    zip.AddFile(xls, "Files");
                }
                if (pdf != string.Empty)
                {
                    zip.AddFile(pdf, "Files");
                }

                Response.Clear();
                Response.BufferOutput = false;
                string zipName = String.Format("Zip_{0}.zip", DateTime.Now.ToString("yyyyMMMddHHmmss"));
                Response.ContentType = "application/zip";
                Response.AddHeader("content-disposition", "attachment; filename=" + zipName);
                zip.Save(Response.OutputStream);
                Response.End();
            }
        }
    }
}