how can i call javascript functions with ScriptManager.RegisterStartUpScript inside handler.ashx file?

Question

i have a repeater like below :

                    <asp:Repeater ID="Repeater1" runat="server">
                        <ItemTemplate>
                            <asp:HyperLink ID="HyperLink1" runat="server" NavigateUrl='<%# Eval("FilePath","~/HandlerForRepeater.ashx?path={0}") %>'><%# Eval("FileName")%></asp:HyperLink>
                            <br />
                            <asp:Label ID="Label3" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "FileCreationDate", "{0:tt h:m:s - yyyy/MM/dd}") %>'></asp:Label>
                            <hr />
                        </ItemTemplate>
                    </asp:Repeater>

i have an HandlerForRepeater.ashx for save as dialog like below :

 using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;

    namespace FileExplorer
    {
        /// <summary>
        /// Summary description for HandlerForRepeater
        /// </summary>
        public class HandlerForRepeater : IHttpHandler, System.Web.SessionState.IRequiresSessionState
        {

            private HttpContext _context;
            private HttpContext Context
            {
                get
                {
                    return _context;
                }
                set
                {
                    _context = value;
                }
            }

            public void ProcessRequest(HttpContext context)
            {
                Context = context;
                string filePath = context.Request.QueryString["path"];
                filePath = context.Server.MapPath(filePath);

                if (filePath == null)
                {
                    return;
                }

                System.IO.StreamReader streamReader = new System.IO.StreamReader(filePath);
                System.IO.BinaryReader br = new System.IO.BinaryReader(streamReader.BaseStream);

                byte[] bytes = new byte[streamReader.BaseStream.Length];

                br.Read(bytes, 0, (int)streamReader.BaseStream.Length);

                if (bytes == null)
                {
                    return;
                }

                streamReader.Close();
                br.Close();
                string fileName = System.IO.Path.GetFileName(filePath);
                string MimeType = GetMimeType(fileName);
                string extension = System.IO.Path.GetExtension(filePath);
                char[] extension_ar = extension.ToCharArray();
                string extension_Without_dot = string.Empty;
                for (int i = 1; i < extension_ar.Length; i++)
                {
                    extension_Without_dot += extension_ar[i];
                }

                //if (extension == ".jpg")
                //{ // Handle *.jpg and
                //    WriteFile(bytes, fileName, "image/jpeg jpeg jpg jpe", context.Response);
                //}
                //else if (extension == ".gif")
                //{// Handle *.gif
                //    WriteFile(bytes, fileName, "image/gif gif", context.Response);
                //}

                if (HttpContext.Current.Session["User_ID"] != null)
                {
                    WriteFile(bytes, fileName, MimeType + " " + extension_Without_dot, context.Response);
                }
                else
                {
System.Web.UI.ScriptManager.RegisterStartupScript(this, this.GetType(), "MyMethod", "alert('You Can Not Download - pzl Login First');", true);
                }
            }

            private void WriteFile(byte[] content, string fileName, string contentType, HttpResponse response)
            {
                response.Buffer = true;
                response.Clear();
                response.ContentType = contentType;

                response.AddHeader("content-disposition", "attachment; filename=" + fileName);

                response.BinaryWrite(content);
                response.Flush();
                response.End();
            }

            private string GetMimeType(string fileName)
            {
                string mimeType = "application/unknown";
                string ext = System.IO.Path.GetExtension(fileName).ToLower();
                Microsoft.Win32.RegistryKey regKey = Microsoft.Win32.Registry.ClassesRoot.OpenSubKey(ext);
                if (regKey != null && regKey.GetValue("Content Type") != null)
                    mimeType = regKey.GetValue("Content Type").ToString();

                    return mimeType;
                }

                public bool IsReusable
                {
                    get
                    {
                        return false;
                    }
                }
            }
        }

every thing is ok about this handler , but i want to show an alert to my users if Session["User_ID"] is Null!
so my problem is in below line :

System.Web.UI.ScriptManager.RegisterStartupScript(this, this.GetType(), "MyMethod", "MyMethod();", true);

and this line has error in this hadler!
how can i call such these javascript methods in HandlerForRepeater.ashx?

thanks in advance

Justin · Accepted Answer · 2011-10-11 19:37:14Z

1

You should be doing that from the page your repeater control is on not the handler. In the code behind for the page with repeater:

if(HttpContext.Current.Session["User_ID"] != null)
{
    Response.Redirect("~/HandlerForRepeater.ashx?path={FilePath}");
}
else
{
    ClientScript.RegisterStartupScript(this.GetType(), "MyMethod", "MyMethod();", true);
}

You can just output the file from that page but trying to stick to your current example as much as possible.

answered Oct 11, 2011 at 19:37

Justin

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5 Comments

SilverLight Over a year ago

thanks for answer / but which server - side event should i use?

Justin Over a year ago

I would change the hyperlink to a link button and use it's click event.

SilverLight Over a year ago

thanks bro - you saved me - i used CommandName in LinkButton!

SilverLight Over a year ago

at last i just want to know was that possible to do that job in handler file ?

Justin Over a year ago

Short answer - no. The handler is not a page, it will not register script on the calling page.

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