ASP.NET

Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        If Request.Cookies("UserName") IsNot Nothing Then
            Response.Cookies.Set(Request.Cookies("UserName"))
        Else
            Response.Cookies.Set(New HttpCookie("UserName", ""))
        End If
        Response.Cookies("UserName").Expires = Now.AddMinutes(30)
    End Sub

    Protected Overloads Overrides Sub OnPreRender(ByVal e As System.EventArgs)
        If Response.Cookies("UserName").Value = Request.Cookies("UserName").Value Then
            Response.Cookies.Remove("UserName")
        End If
        MyBase.OnPreRender(e)
    End Sub

If Log.Statu = LoginEnum.OK Then
            HttpContext.Current.Response.Cookies("UserName").Value = row("username")
            HttpContext.Current.Response.Cookies("UserName").Expires = Now.AddMinutes(30)
End If

HttpContext.Current.Response.Cookies("UserName").Expires = Now.AddMinutes(-30)

<br />
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="adm_add_property.aspx.vb" Inherits="rentaholiday.adm_add_property"  MasterPageFile ="~/Administration/Admin/admin.Master"%><br />

protected void btn_add_issue1_Click(object sender, EventArgs e)
    {
        DataTable tbl1 = dt.filltbl("select * from tbl_issue where id=-1", "new1");
        DataRow row1 = tbl1.NewRow();
        row1["issue_id"] = ViewState["max"].ToString(); ;
        row1["prefix"] = ViewState["prefix"].ToString();
        row1["Project_id"] = Convert.ToInt32(ddl_projects.SelectedValue);
        row1["project_name"] = Convert.ToString(ddl_projects.SelectedItem);
        row1["issue_title"] = txt_issue.Text;
        row1["issue_type"] = Convert.ToString(ddl_issue.SelectedItem);
        row1["issue_desc"] = FreeTextBox1.Text;
        row1["status"] = "Open";
        row1["svdate"] = DateTime.Now.Date.ToShortDateString();
        row1["svtime"] = DateTime.Now.ToShortTimeString();
        tbl1.Rows.Add(row1);
        dt.update(tbl1, "select * from tbl_issue");
        
        fillissueid();
        FreeTextBox1.Text = "";
        txt_issue.Text = "";
        
        object max = dt.getmax("select max(id) from tbl_issue");
        if (fu_attachment.FileName != "")
        {
            DataTable tblco = dt.filltbl("select * from tbl_issue where id=" + max, "maxx");
            DataRow r1 = tblco.Rows[0];
            string a = Convert.ToString(max);
            string str = "~/Data1/";
            str = Server.MapPath(str);
            str = str + a ;
            fu_attachment.SaveAs(str);
            r1["issue_attach"] = "~/Data1/" + a ;
            dt.update(tblco, "select * from tbl_issue");
        }
        Page.RegisterStartupScript("myrest", "<script>alert('New issue was added successfully');</script>");
        Response.Redirect("default.aspx");
    }