CollapsiblePanelExtender Click Event

Question

I have a a CollapsiblePanelExtender with the usual extend and collapse buttons....I would like to have a click event fire off when the extender is extended and a different click event fire off when the extender is collapsed. But the most important event is when it is extended. I could live without a click even on collapse.

Most of the examples I've found online searching using: "CollapsiblePanelExtender" "click event" is having the extender react based on a click even else where...

I want the extender to fire off a JS when clicked.

How should I go about accomplishing this? Am I asking the wrong question/using the wrong search strings?

            CollapsiblePanelExtender extendatron = new CollapsiblePanelExtender();
            extendatron.ID = "cpe" + MenuId;
            extendatron.TargetControlID = "pnlContent" + strMenuId;
            extendatron.ExpandControlID = "pnlMenu" + strMenuId;
            extendatron.CollapseControlID = "pnlMenu" + strMenuId;
            extendatron.Collapsed = bCollapsed;
            extendatron.TextLabelID = strMenuName;
            extendatron.ExpandedText = m_strButtonLabelHide;
            extendatron.CollapsedText = m_strButtonLabelShow;
            extendatron.ImageControlID = "imglnk" + strMenuId;
            extendatron.CollapsedImage = "~/App_Themes/default/nbExpand.gif";
            extendatron.ExpandedImage = "~/App_Themes/default/nbCollapse.gif";
            extendatron.SuppressPostBack = true;
            extendatron.ScrollContents = false;

            var extender = $find('extendatron'); //this would be <%=myExtender.ClientID%>
            extender.add_collapsed( function() { alert('collapsed'); });
            extender.add_expanded( function() { alert('expanded'); });

Answer 1

I assume you're talking about the ASP.Net AJAX Control Toolkit. You can add handlers to the collapsed and expanded events as follows:

//this would be <%=myExtender.ClientID%> when using a master page
var extender = $find('myExtender_ClientId'); 
extender.add_collapsed( function() { alert('collapsed'); });
extender.add_expanded( function() { alert('expanded'); });

Let me know if you have any questions...I've done a fair bit of customizing some of these objects in various solutions.

Answer 2

First, you need to create a client side (JavaScript) onClick event for the panel or control users are clicking on.

So, go in there type onClick="functionName();"

<asp:Panel ID="pDocumentHeaderTitle" runat="server" CssClass="collapsePanelHeader" onClick="setCollapseState();"> 
       <asp:Image ID="imgDocumentHeaderHeader" runat="server" ImageUrl="~/images/wadown.gif"/>Document Header
       <asp:Label ID="lblDocumentHeaderHeader" runat="server">(Show)</asp:Label>
</asp:Panel>

Next: Add this javascript.

<script type="text/javascript">
    function setCollapseState() {
        var extenderDocumentHeader = document.getElementById("MainContent_cpeDocumentHeader_ClientState");
        setCookie("cpeDocumentHeaderStatus", extenderDocumentHeader.value, 5)
    }

    //W3Schools cookie code.
    function setCookie(c_name, value, exdays) {
        var exdate = new Date();
        exdate.setDate(exdate.getDate() + exdays);
        var c_value = escape(value) + ((exdays == null) ? "" : "; expires=" + exdate.toUTCString());
        document.cookie = c_name + "=" + c_value;
    }

    //W3Schools cookie code.
    function getCookie(c_name) {
        var i, x, y, ARRcookies = document.cookie.split(";");
        for (i = 0; i < ARRcookies.length; i++) {
            x = ARRcookies[i].substr(0, ARRcookies[i].indexOf("="));
            y = ARRcookies[i].substr(ARRcookies[i].indexOf("=") + 1);
            x = x.replace(/^\s+|\s+$/g, "");
            if (x == c_name) {
                return unescape(y);
            }
        }
    }

</script>

Notice, when your page is loaded, there is a hidden field that is your collapsible panels state. It will be true or false. Go to page source and search for it you will find it.

Then add:

var extenderDocumentHeader = document.getElementById("MainContent_cpeDocumentHeader_ClientState");

So on click, get this clients state, save it in a cookie and your good to go!