Cookies are domain specific and cannot be used across different network domains. The only domain that can read a cookie is the domain that sets it. It does not matter what domain name you set.
Cookies are used to store small pieces of information on a client machine. A cookie can store only up to 4 KB of information. Generally cookies are used to store data which user types frequently such as user id and password to login to a site.

The HttpCookie class defined in the System.Web namespace represents a browser cookie.


Creating cookies (C#)

Dim cookie As HttpCookie = New HttpCookie("UID")
cookie.Value = "id"
cookie.Expires = #3/30/2010#
Response.Cookies.Add(cookie)
cookie = New HttpCookie("username")
cookie.Value = "username"
cookie.Expires = #3/31/2010#
Response.Cookies.Add(cookie)

Creating cookies (VB.NET)

 HttpCookie cookie = Request.Cookies["Preferences"];
      if (cookie == null)
      {
        cookie = new HttpCookie("Preferences");
      }

      cookie["Name"] = txtName.Text;
      cookie.Expires = DateTime.Now.AddYears(1);
      Response.Cookies.Add(cookie);



Creating cookies (C#)

    HttpCookie MyCookie = new HttpCookie("Background");
    MyCookie.Value = "value";
    Response.Cookies.Add(MyCookie);


Reading cookies  (VB.NET)

Dim cookieCols As New HttpCookieCollection
cookieCols = Request.Cookies
Dim str As String

' Read and add all cookies to the list box

For Each str In cookieCols
ListBox1.Items.Add("Value:" Request.Cookies(str).Value)
Next
 

Reading cookies (C#)

 ArrayList colCookies = new ArrayList();
        for (int i = 0; i < Request.Cookies.Count; i++)
            colCookies.Add(Request.Cookies[i]);

        grdCookies.DataSource = colCookies;
        grdCookies.DataBind();


Deleting cookies (VB.NET)

Dim cookieCols As New HttpCookieCollection
cookieCols = Request.Cookies
Dim str As String
' Read and add all cookies to the list box
Request.Cookies.Remove("PASS")
Request.Cookies.Remove("UID")


Deleting cookies (C#)

string[] cookies = Request.Cookies.AllKeys;
        foreach (string cookie in cookies)
        {
            ListBox1.Items.Add("Deleting " + cookie);
            Response.Cookies[cookie].Expires = DateTime.Now.AddDays(-1);
        }