How to prevent/stop event bubbling/propagation on page load in asp.net

Question

I would like to know if I can prevent the event bubbling / propagation on the page load based on condition like:

protected override void OnLoad(EventArgs e)
{
    // If the user press F5 from the browser
    if (IsRefresh)
    {
        // Here I want to stop propagation/bubbling the events like OnClick of a submit button but without using the button object (I want it generic)
    }
    else
    {
        base.OnLoad(e);
    }
}

Is this possible?

Answer 1

Prevent the event bubbling has two difficulties - detect the F5 and stop the events - i would simply use the Post/Redirect/Get-pattern:

protected void Button1_Click(object sender, System.EventArgs e)
{
    // do what you need to do
    // now redirect to the same page, 
    // then a browser-refresh via F5 won't trigger this event again
    Response.Redirect(Request.Url.PathAndQuery);
}

Answer 2

I did once in ASP.NET WebForms project when user press on F5 it'll do something other than refresh, I done this by use jQuery keypress even for the page and call e.preventDefault(); check this

Update:

$(document).ready(){function(){
        this.keydown(e){
          if (e.which == 116){
                  e.preventDefault();
             window.location.href = "http://foo.com/?IsReferesh=1";     
           }
        };    
)};

You can use the QueryString to check if user press F5 and the reflection in Code Behind. If I missed something, then I didn't fully understand your question.

Answer 3

Regarding the specifics of your question, how about inverting it? Maybe add a Load event listener (say, in page Init) only if the condition is not met.

Another option might be doing something like:

this.Load -= MyPageLoadMethod;

You are likely looking at the event itself, not the OnLoad method. Eitherway, I think it is possible, see some options here How to remove all event handlers from a control

There is a big "BUT" though...

---

Like most people here, I think you are not solving the right problem. I'm sorry the same applies for Emad's solution I think.

Tim nailed it. This answer will try to explain this option more.

The pattern Post-Get-redirect is very popular and very standard. In most of our applications, submitting the same form more than once either by re-clicking the submit button before page loading or refreshing the browser causing another POST call is wrong, so, the practice of redirect after a non-AJAX form submission has become so standard.

Everything else you may try will be no more of a dirty workaround than a proper solution.

--

Now, comes the problem of providing feedback to the user. Ruby On Rails provides a nifty helper for this called Flash helper. It's a message you can set before redirecting (or even in the same page if there is no redirect) and the next time you display it, it'll destroy itself, the next time you call it, you get nothing. so, you display nothing.

ASP.NET MVC has something like this which is TempData. TempData can be stored in many places, by default in the Session, so, if you are redirecting from an MVC action, you can set something like TempData['Message'] , and read it in the next Controller. ASP.NET MVC will handle removing it after the redirect.

So, how about Webforms? There's nothing to prevent you from doing it too. It really isn't rocket science

• You can check for URL Referrer whether it is an edit page or not and display message based on that.

• You can store a message in Session before redirect, and check for it in every page load, if found, you display it and delete it from Session

• If Session is disabled, you can use cookies. You can check the date of the cookie before sending, so that if the redirect never happened (use network dropped or whatever) and use came to the page later in the time he doesn't see an outdated message.

• You can also store in Cache (with some key related to user of course, as Cache is application wide), You can then set the Cache expiration to some short period to avoid the problem explained in cookies option

You can also google for Rails Flash-like for ASP.NET Webforms to see what reusable components other people came up with. This result for example came in my search:
http://highoncoding.com/Articles/542_Creating_Rails_Like_Flash_Feature_in__NET_The_Flash_Control.aspx
Check NuGet also maybe there's something there. Again, it's not hard to build your own anyway.

---

Update:

Another simple approach might be to just redirect to the same URL, this'll cause a GET request and will not run any handler, pretty close to the original implementation of Post-Get-Redirect (yours will be Post-Post-Redirect maybe, kidding), and pretty safe as well.

Something like:

Response.Redirect(Request.RawUrl);

Update 2

Just as mentioned above, if you are running after page init, say in page Load, you can always emove events in a way similar to:

this.SubmitButton.Click -= SubmitButton_Click;

You get the idea...

That's useful if what you want is stop particular events, while the previous bits of the answer were assuming you are trying to stop most of the events.

http://gurustop.net

Answer 4

protected override void OnLoad(EventArgs e)
{
        if (!IsPostBack)
        {
            if (Request.UrlReferrer != null)
                if (Request.UrlReferrer.PathAndQuery == Request.RawUrl)
                {
                    // Show Message
                }
        }
}

protected void Button1_Click(object sender, System.EventArgs e)
{   
     Response.Redirect(Request.Url.PathAndQuery);
}

Note:

if (Request.UrlReferrer.PathAndQuery == Request.RawUrl) // does not work with chrome so you can replace it with if (Request.UrlReferrer.AbsolutePath == Request.Url.AbsolutePath)

Answer 5

    static string REFRESH_CHECK_GUID = "REFRESH_CHECK_GUID";

    protected void Page_Load(object sender, EventArgs e)
    {
        if (ViewState[REFRESH_CHECK_GUID] != null && !ViewState[REFRESH_CHECK_GUID].ToString().Equals(Session[REFRESH_CHECK_GUID].ToString()))
        {
            Response.Redirect("Login.Aspx");
        }

        Session[REFRESH_CHECK_GUID] = System.Guid.NewGuid().ToString();
        ViewState[REFRESH_CHECK_GUID] = Session[REFRESH_CHECK_GUID];