State Management

Re: how to delete cookies?

sandy060583 — Fri, 03 Jul 2009 11:19:06 GMT

here is the code to create the cookie & delete it...

                        //Create Cookie
                        HttpCookie aCookie = new HttpCookie("AdminInfo");
                        aCookie.Values["userName"] = txtUsername.Text;
                        aCookie.Values["Password"] = txtPassword.Text;
                        aCookie.Values["lastVisit"] = DateTime.Now.ToString();
                        aCookie.Expires = DateTime.Now.AddDays(10);
                        Response.Cookies.Add(aCookie);

                        //Delete Cookie
                        HttpCookie aCookie = new HttpCookie("AdminInfo");
                        aCookie.Expires = DateTime.Now.AddDays(-1);
                        Response.Cookies.Add(aCookie);

Hope this will help u..

Re: how to delete cookies?

klpatil — Wed, 03 Jun 2009 05:04:10 GMT

Hi,

Thanks for all your help i just have one suggestion that without creating a new cookie with same name we can also take instance of already existing cookie[As we are going to delete a cookie so it must exist :)] and then set its expires date and set it back in response...for PoC i have created one static function which you can use by just passing the cookie name to delete. Here it is :

        /// &lt;summary&gt;
        /// This function will be used to remove
        /// cookies value
        /// </summary>
        /// <param name="key"></param>
        /// <returns>Cookies value</returns>
        public static void RemoveCookie(string key)
        {
            //get cookies value
            HttpCookie cookie = null;
            if (HttpContext.Current.Request.Cookies[key] != null)
            {
                cookie = HttpContext.Current.Request.Cookies[key];
                //You can't directly delte cookie you should
                //set its expiry date to earlier date
                cookie.Expires = DateTime.Now.AddDays(-1);
                HttpContext.Current.Response.Cookies.Add(cookie);
            }
            
        }

Re: how to delete cookies?

satender88 — Sun, 02 Mar 2008 15:40:57 GMT

Hi.

This works:

        Dim iharyanacookie As HttpCookie
        iharyanacookie = New HttpCookie("username", "abc")
        iharyanacookie.Expires = DateTime.Now.AddYears(-30)
        Response.Cookies.Add(iharyanacookie)
        Response.Redirect("http://www.iharyana.com")

Thanks gopalanmani, thanks a ton

Re: how to delete cookies?

satender88 — Sun, 02 Mar 2008 15:19:48 GMT

Hi ivanatanasov,

It is showing following error:

Server Error in '/' Application.

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 72:         Response.Cookies.Remove("iharyanacookie")
Line 73: 
Line 74:         Request.Cookies("iharyanacookie").Expires = DateTime.Now.AddYears(-30)
Line 75:         Request.Cookies.Remove("iharyanacookie")
Line 76:         Response.Redirect("http://www.iharyana.com")

Source File: d:\hosting\satender88\login.ascx.vb Line: 74

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.]
   WebUserControl.logout_Click(Object sender, EventArgs e) in d:\hosting\satender88\login.ascx.vb:74
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +105
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +107
   System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +7
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +11
   System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +33
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +5102

Version Information: Microsoft .NET Framework Version:2.0.50727.832; ASP.NET Version:2.0.50727.832

Re: how to delete cookies?

gopalanmani — Sat, 01 Mar 2008 18:25:56 GMT

hi,

Deleting Cookies

Deleting a cookie—physically removing it from the user's hard disk—is a variation on modifying it. You cannot directly remove a cookie because the cookie is on the user's computer. However, you can have the browser delete the cookie for you. The technique is to create a new cookie with the same name as the cookie to be deleted, but to set the cookie's expiration to a date earlier than today. When the browser checks the cookie's expiration, the browser will discard the now-outdated cookie. The following code example shows one way to delete all the cookies available to the application:

Dim aCookie As HttpCookie
Dim i As Integer
Dim cookieName As String
Dim limit As Integer = Request.Cookies.Count - 1
For i = 0 To limit
    cookieName = Request.Cookies(i).Name
    aCookie = New HttpCookie(cookieName)
    aCookie.Expires = DateTime.Now.AddDays(-1)
    Response.Cookies.Add(aCookie)
Next

check this url regarding cookies,

http://msdn2.microsoft.com/en-us/library/ms178194.aspx

Re: how to delete cookies?

ivanatanasov — Sat, 01 Mar 2008 13:06:41 GMT

hi boy,

Logout Button:

    Protected Sub logout_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles logout.Click
        Response.Cookies("iharyanacookie").Expires = DateTime.Now.AddYears(-30)
        Response.Cookies.Remove("iharyanacookie")

         Request.Cookies("iharyanacookie").Expires = DateTime.Now.AddYears(-30)
        Request.Cookies.Remove("iharyanacookie")
        Response.Redirect("http://www.iharyana.com")

    End Sub
End Class

how to delete cookies?

satender88 — Sat, 01 Mar 2008 12:08:42 GMT

Hi,
I am creating a cookie using the following code:
                Dim iharyanacookie As HttpCookie
                iharyanacookie = New HttpCookie("username", uid.Text)
                Response.Cookies.Add(iharyanacookie)

But how can I delete or destroy a cookies. I using the following code about cookies is still there and working.
        Response.Cookies("iharyanacookie").Expires = DateTime.Now.AddYears(-30)
        Response.Cookies.Remove("iharyanacookie")
        Response.Redirect("http://www.iharyana.com")

Basically the whole page code is:

Imports System.Data.SqlClient

Partial Class WebUserControl
Inherits System.Web.UI.UserControl

Login Button:

Protected Sub login_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles login.Click
        login_error.Text = ""
        Dim conn1 As SqlConnection
        Dim comm1 As SqlCommand
        Dim reader1 As SqlDataReader
        Dim connstring1 As String

        connstring1 = ConfigurationManager.ConnectionStrings("iharyana").ConnectionString

        conn1 = New SqlConnection(connstring1)

        Dim users As String
        users = "select password from usermain where username = @username"

        comm1 = New SqlCommand(users, conn1)

        comm1.Parameters.Add("@username", Data.SqlDbType.VarChar, 20)
        comm1.Parameters("@username").Value = uid.Text

        conn1.Open()

        reader1 = comm1.ExecuteReader

        If reader1.Read Then
            Dim pass As String
            pass = reader1.Item("password")
            If (pass = password.Text) Then
                'create cookies
                Dim iharyanacookie As HttpCookie
                iharyanacookie = New HttpCookie("username", uid.Text)
                Response.Cookies.Add(iharyanacookie)
                Response.Redirect("http://www.iharyana.com")

            Else
                login_error.Text = "Invalid Login ID or Password! Try Again"
            End If

        End If

        reader1.Close()
        conn1.Close()

    End Sub

Page Load:

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim iharyanacookie As HttpCookie
        iharyanacookie = Request.Cookies("username")
        If iharyanacookie Is Nothing Then

        Else
            user.Text = "Welcome back <b>" & iharyanacookie.Value & "</b>"
            uid.Visible = False
            pass.Visible = False
            password.Visible = False
            login.Visible = False
            forgot.Visible = False
            sep.Visible = False
            reg.Visible = False
            my.Visible = True
            logout.Visible = True

        End If
    End Sub

Pls pls help.