Why MyFile Upload Has Not containg file during Autopostback

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C#

ASP.NET

C#4.0

File-Upload

I use this code for Upload a Image and also for update it,But i found that During Autopostback my fileupload doesn't contain image,Is there any solution for that.

<div class="form-group">
            <asp:Label for="inputEmail1" class="col-md-2 control-label" ID="lblimage"
                meta:resourcekey="lblBannerSignUp" Text="Image" runat="server"></asp:Label>

            <div class="col-md-3">
             <asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="conditional">
                                    <Triggers>
                                        <asp:PostBackTrigger ControlID="btnSubmit" />
                                    </Triggers>
                                    <ContentTemplate>
                                         <asp:FileUpload  ID="fuimage" runat="server" meta:resourcekey="fuimage123" />
                                    </ContentTemplate>
                                </asp:UpdatePanel>

            </div>
             <div class="col-md-10 pull-right">
            <img id="imagezoom" runat="server" />

             <%--   <asp:Image ID="imagezoom" runat="server" />--%>
                <%-- <asp:PlaceHolder ID="pnll" runat="Server"></asp:PlaceHolder >--%>
            </div>
            </div>

code for .cs file

EventManager_SuperAdmin m;
        protected void Page_Load(object sender, EventArgs e)
        {
            m = (EventManager_SuperAdmin)Page.Master;
            
            if (Session["FileUpload1"] == null && fuimage.HasFile)
            {
                Session["FileUpload1"] = fuimage;

            }
           
            else if (Session["FileUpload1"] != null && (!fuimage.HasFile))
            {
                fuimage = (FileUpload)Session["FileUpload1"];

            }
            
            else if (fuimage.HasFile)
            {
                Session["FileUpload1"] = fuimage;

            }
            if (Session["name"] == null)
            {
                Response.Redirect("~/SuperAdmin/Default.aspx");
            }

            if (!this.IsPostBack)
            {

                m.bussinesCollection.IDSecurity.Decrypt(Request.QueryString["id"]);

                if (Request.QueryString["id"] != null)
                {

                    var result1 = m.bussinesCollection.FeaturesBL.GetFeatureByFeatureID(Convert.ToInt32(m.bussinesCollection.IDSecurity.Decrypt(Request.QueryString["id"])));
                    txttitle.Text = result1.Title;
                    CKEditor1.Text = result1.Text;
                    fuimage.Attributes.Add("FileName", result1.Image);
                    imagezoom.Src = "/SuperAdmin/Images/" + result1.Image;

                    if (result1.Show_at_home == "Yes")
                    {
                        Chckshowfeatures.Checked = true;
                    }
                    else
                    {
                        Chckshowfeatures.Checked = false;
                    }

                }
            }



        }

        protected void btnSubmit_Click(object sender, EventArgs e)
        {

            if (Request.QueryString["id"] != null)
            {



                string image = fuimage.FileName;

                if (fuimage.HasFile)
                {

                    string Extention = System.IO.Path.GetExtension(fuimage.FileName);
                    if (Extention.ToLower() == ".jpg" || Extention.ToLower() == ".jpeg" || Extention.ToLower() == ".bmp" || Extention.ToLower() == ".png" || Extention.ToLower() == ".gif")
                    {


                        var path = Server.MapPath("Images/" + fuimage.FileName);
                        fuimage.SaveAs(path);

                    }
                }

                if (Chckshowfeatures.Checked == true)
                {
                    m.bussinesCollection.FeaturesBL.Show_at_home = "Yes";
                }
                else
                {
                    m.bussinesCollection.FeaturesBL.Show_at_home = "False";
                }
                m.bussinesCollection.FeaturesBL.UpdateFeatures(Convert.ToInt32(m.bussinesCollection.IDSecurity.Decrypt(Request.QueryString["id"])), txttitle.Text, CKEditor1.Text,image, m.bussinesCollection.FeaturesBL.Show_at_home);

                lblmsg.Visible = true;
                //  lblmsg.Text = "Records updated successfully.";
                Response.Redirect("ListOfFeatures.aspx");
            }
            else
            {
                if (fuimage.HasFile)
                {
                    string Extention = System.IO.Path.GetExtension(fuimage.FileName);
                    if (Extention.ToLower() == ".jpg" || Extention.ToLower() == ".jpeg" || Extention.ToLower() == ".bmp" || Extention.ToLower() == ".png" || Extention.ToLower() == ".gif")
                    {


                        var path = Server.MapPath("Images/" + fuimage.FileName);
                        fuimage.SaveAs(path);
                      // this.Session["fileuploadforupdate"] = fuimage;
                    }
                }

                m.bussinesCollection.FeaturesBL.Title = txttitle.Text;
                m.bussinesCollection.FeaturesBL.Text = CKEditor1.Text;
             //   m.bussinesCollection.FeaturesBL.Image = "~/SuperAdmin/Images/"+fuimage.FileName;
                m.bussinesCollection.FeaturesBL.Image =fuimage.FileName;
                if (Chckshowfeatures.Checked == true)
                {
                    m.bussinesCollection.FeaturesBL.Show_at_home = "Yes";
                }
                else
                {
                    m.bussinesCollection.FeaturesBL.Show_at_home = "False";
                }
                m.bussinesCollection.FeaturesBL.Insert();

                txttitle.Text = "";
                CKEditor1.Text = "";

                lblmsg.Visible = true;
                //  lblmsg.Text = "Records Inserted Successfully";
                Response.Redirect("ListOfFeatures.aspx");

            }
        }

I also try with session but it is not help me.

If there is any other solution ?

Thanks in advance.