Question

I need to allow a user to redirect from a page that collects user input. Should the user redirect, upon return to the page the form should be filled in with the values that the user had already entered.

I completed the following but I’m guessing there is a better way to do this.

On RedirectEvent()
{
    Dictionary<string, string> form = new Dictionary<string, string>();
    foreach (string key in Request.Form.AllKeys)
    {
        if (key != null)
        form.Add(key, Request.Form[key]);
    }
    Session["requestFormKeys"] = form;

    Response.Redirect(url);
}


On Page_Load(object sender, EventArgs e)
{
    if (Session["requestFormKeys"] != null)
    {
        Dictionary<string, string> form = Session["requestFormKeys"] as   Dictionary<string, string>;
        // I tried using 'Request.Form.AllKeys' here but it was always null
        foreach (KeyValuePair<string, string>pair in form)
        {
            // cannot use a switch because switch requires a constant (value must be known at compile time)
            if (pair.Key.Contains("txtName"))
                    txtName.Text = lblNameView.Text = pair.Value;
            else if (pair.Key.Contains("ddlType"))
                    ddlType.SelectedValue = pair.Value;
            else if (pair.Key.Contains("ddlPriority"))
                    ddlPriority.SelectedValue = pair.Value;
                              .
                              .
                              .         
            //this is a tedious process and should be streamlined
                              .
                              .
                              .
            else if (pair.Key.Contains("txtDateStart"))
                    txtDateStart.Text = pair.Value;
            else if (pair.Key.Contains("txtDateEnd"))
                    txtDateEnd.Text = pair.Value;

        }
   }
   Session.Remove("requestFormKeys");
  }
}

Any help would be appreciated.

Answer 1

Assuming a database is out of the question because we are dealing with an anonymous user – putting the dictionary in the Session could be a little heavy on server resources – unless you run a separate stateserver or sqlserver for the session.

Persisting the values in a client side cookie collection would work for an anonymous user – though increase bytes over the wire.

Response.Cookies["mypage"]["textbox1"] = textbox1.Text;
Response.Cookies["mypage"]["textbox2"] = textbox2.Text;

Remember to HTML encode the cookie in case the cookie has been hacked with client-side script on the way back

if (Request.Cookies["mypage"] != null)
textbox1.Text = Server.HtmlEncode(Request.Cookies["mypage"]["textbox1"].Value);