ASP.NET: Recursively Writing all Form Elements to a Cookie

Wednesday, November 12, 2008

There are instances when you need to write all your form elements on a page to a cookie. Here's a simple recursive function, which will write all form values to cookies with the form ids as the cookie keys:

   Private Sub AddToCookie(ByVal Parent)   'Add form values to cookies
       For Each c As Control In Parent.Controls
           If (TypeOf c Is TextBox) Then
               Response.Cookies("Order")(c.ID) = CType(c, TextBox).Text
           ElseIf (c.ID = "Product") Then 'Getting value from a DropDownBox
               Response.Cookies("Order")(c.ID) = CType(c, DropDownList).SelectedValue
           End If
           If (c.Controls.Count > 0) Then
               AddToCookie(c)
           End If
       Next
   End Sub

This function finds all textboxes and a drop-down box on the page and writes it onto a cookie. This function can also be modified for storing values in session variables.

To retrieve all values of the cookie iteratively, the following code snippet can be used:

       For cookie As Integer = 0 To Request.Cookies("Order").Values.Count - 1
           lblOrderInfo.Text += Request.Cookies("Order").Values.Keys.Get(cookie) & "  =   "
           lblOrderInfo.Text += Request.Cookies("Order")(Request.Cookies("Order").Values.Keys.Get(cookie)) & "<br/>"
       Next

This code displays all the elements of the cookie as: key = value.

This VB.Net code can be converted to C# by using this converter.