asp.net Multiple Page_Load events for a user contr

Question

I've recently set up an ASP.net site (not using MVC.net) to use URL Routing (more on the code below) - when using user controls on the site (i.e I've created a "menu" user control to hold menu information) the page_load event for that control will fire twice when URLs have more than one variable passed over.

i.e.

pageName/VAR1 : will only fire the page_load event once.

while

pageName/VAR1/VAR2 : will fire the page_load event twice.

*Multiple extra VARs added on the end will still only fire the page_load event twice*.

---

Below are the code snippits from the files, the first is the MapPageRoute, located in the Global.asax :

// Register a route for the Example page, with the NodeID and also the Test123 variables allowed.
// This demonstrates how to have several items linked with the page routes.
    routes.MapPageRoute(
        "Multiple Data Example",                    // Route name
        "Example/{NodeID}/{test123}/{variable}",     // Route URL - note the NodeID bit
        "~/Example.aspx",                            // Web page to handle route
        true,                                        // Check for physical access
        new System.Web.Routing.RouteValueDictionary 
        { 
            { "NodeID", "1" },        // Default Node ID
            { "test123", "1" },       // Default addtional variable value
            { "variable", "hello"}    // Default test variable value
        }  
    );

Next is the way I've directed to the page in the menu item, this is a list item within a UL tag :

<li class="TopMenu_ListItem"><a href="<%= Page.GetRouteUrl("Multiple Data Example", new System.Web.Routing.RouteValueDictionary { { "NodeID", "4855" }, { "test123", "2" } }) %>">Example 2</a></li>

And finally the control that gets hit multiple times on a page load :

// For use when the page loads.
    protected void Page_Load(object sender, EventArgs e)
    {
        // Handle the routing variables.
        // this handles the route data value for NodeID - if the page was reached using URL Routing.
        if (Page.RouteData.Values["NodeID"] != null)
        {
            nodeID = Page.RouteData.Values["NodeID"] as string;
        };

        // this handles the route data value for Test123 - if the page was reached using URL Routing.
        if (Page.RouteData.Values["Test123"] != null)
        {
            ExampleOutput2.Text = "I am the output of the third variable : " + Page.RouteData.Values["Test123"] as string;
        };

        // this handles the route data value for variable - if the page was reached using URL Routing.
        if (Page.RouteData.Values["variable"] != null)
        {
            ExampleOutput3.Text = "I say " + Page.RouteData.Values["variable"] as string;
        };
    }

Note, that when I'm just hitting the page and it uses the default values for items, the reloads do not happen.

---

Any help or guidance that anyone can offer would be very much appreciated!

EDIT : The User Control is only added to the page once. I've tested the load sequence by putting a breakpoint in the page_load event - it only hits twice when the extra routes are added.

EDIT2 : Thanks again to those who've helped out so far - I'm still having trouble finding the cause of the double load - does anyone else have any more suggestions?

EDIT3/Answer : The answer below explains how to fix the problem - essentially remove any ../ references to Javascript files from the initial site creation/includes. I hope that this helps anyone else who has this problem!

Thanks in Advance,

Paul Hutson

Answer 1

It's not clear from your question whether or not you have multiple instances of this user control on the page. If so, I believe (though someone may correct me) that the control's page_load event will be fired for each copy.

A way to investigate this issue further is to put a breakpoint in the control's on_load event, and check the call stack each time it stops. It won't give you a definitive cause but, by checking the instance name & ID, etc you may be able to glean some more information.

Answer 2

I have gone around and around with this problem to the point of almost screaming. After commenting all code out i nailed the issue down to an iFrame with the an src attribute set with a default of '#'

I hope this helps someone.

Answer 3

I dont know why but if you use visual to create asp project will have this code

<asp:PlaceHolder ID="PlaceHolder1" runat="server">
    <link href="favicon.ico" rel="shortcut icon" type="image/x-icon" />
    <script src="<%: ResolveUrl("~/Scripts/modernizr-2.6.2.js") %>"></script>
</asp:PlaceHolder>

If you remove the row

<link href="favicon.ico" rel="shortcut icon" type="image/x-icon" />

event Page_load will load only 1 time. :D it work for me

Answer 4

Simply making sure that no file was referenced using ../ solved the problem entirely - specifically it was the Image files that were causing the problem. ex.- ../Image/xyz.png

When I have removed ../ then page is loading only once

Answer 5

Its possibly you are trying to pass some querystrinvalues to the user control.Ca n you try passing them normally like below.

test.aspx?var1=sample&var2=test

Answer 6

Having tried a number of things I have discovered that if any file has a ../ before it (in an include on any page) it will cause the URL Routing problem described above.

Simply making sure that no file was referenced using ../ solved the problem entirely - specifically it was the Javascript files that were causing the problem.