ASP.NET Back Button for multiple forms - asp.net

Question

I am trying to track navigation between a number of Web Forms in ASP.NET. I've tried the client side back navigation using the following:
<asp:Button ID="BackButton" runat="server" Text="Back"
OnClientClick="JavaScript:window.history.back(1);return false;" />
Unfortunately this does not work for my scenario due to postbacks going on. My scenario has a number of Web Forms:
Page1.1
Page1.2
Page2
Page3
Navigating forward through the pages works similarly to a wizard. There are 2 starting points - from Page1.1 and Page1.2.
Page1.1 -> Page2 -> Page3
Page1.2 -> Page2 -> Page3
So clicking back buttons will have the following navigation:
Page3 -> Page2
Page2 -> Page1.1
Page2 -> Page1.2
There are additional parameters passed between the pages which need to be maintained.
I am currently looking at maintaining something in the Session to maintain the current call stack which somewhat works however, I am getting a build up of referrer urls. At the minute I am just trying to conceptualise this.
I am running this in SharePoint as Application Pages, however each page is essentially an ASP.NET page for the sake of this example.
So I have introduced an abstract class for each Page:
public abstract class SecureLayoutsPageBase : System.Web.UI.Page
{
private PageController _pageController;
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
_pageController = (PageController)Session["PageController"];
if (_pageController == null)
{
_pageController = new PageController();
Session["PageController"] = _pageController;
}
if (!Page.IsPostBack && Page.Request.UrlReferrer != null)
{
this.PageController.History.Push(Page.Request.UrlReferrer.ToString());
}
}
protected PageController PageController
{
get
{
return _pageController;
}
}
}
Which has an instance of PageController:
[Serializable()]
public class PageController
{
private Stack<string> _history = new Stack<string>();
public void Previous(HttpResponse response)
{
string previous = _history.Pop();
response.Redirect(previous);
}
public Stack<string> History
{
get
{
return _history;
}
}
}
Then each page will call the PageController.Previous in the server side event handler for the back button click:
protected void BackButton_Click(object sender, EventArgs e)
{
this.PageController.Previous(this.Response);
}
This issue with this is that calling PageController.Previous still results in the Url being added to the stack. I am just wondering if there is a way to prevent the url getting added when back has been clicked. Or alternative solutions...

Answer 1

History(-1) wont work, because this will include postbacks. Just set the button href dependant on whatever page you're on. If you know itsloaded page 3, set the back button to page 2

Answer 2

OK... couple of tweaks to get my scenario working. Not keen on this solution so any others would be good.
Change to SecureLayoutsPageBase:
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
_pageController = (PageController)Session["PageController"];
if (_pageController == null)
{
_pageController = new PageController();
Session["PageController"] = _pageController;
}
if (!Page.IsPostBack && Page.Request.UrlReferrer != null && Page.Request.Url.ToString() != this.PageController.PreviousUrl)
{
this.PageController.AddHistory(Page.Request.UrlReferrer.ToString());
}
}
Change to PageController:
[Serializable()]
public class PageController
{
private Stack<string> _history = new Stack<string>();
private string _previous;
public void Previous(HttpResponse response)
{
_previous = _history.Pop();
response.Redirect(_previous);
}
public void AddHistory(string url)
{
if(url != _previous)
{
_history.Push(url);
}
}
public Stack<string> History
{
get
{
return _history;
}
}
public string PreviousUrl
{
get
{
return _previous;
}
}
}