[mapguide-users] OnSelectionChanged in AJAX viewer?

Mon Apr 28 09:14:18 EDT 2008

Thanks you both, but I think these don’t work, cause I have Ajax viewer and
OnSelectionChanged is an ActiveX control.

Any ideas with Ajax?

Tanja

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Kenneth,
GEOGRAF A/S
Sent: 28. huhtikuuta 2008 16:01
To: MapGuide Users Mail List
Subject: Re: [mapguide-users] OnSelectionChanged in AJAX viewer?

I made a small mistake.

The retry condition should not be:
if (mapFrame == null)
            window.setTimeout("RetryInit();", 500);

but
if (originalMapFrameOnSelectionChanged == null)
{
    mapFrame = null;
    window.setTimeout("RetryInit();", 500);
}

Because the frame may exist, but the function might be missing.

Regards, Kenneth, GEOGRAF A/S

Kenneth, GEOGRAF A/S skrev: 

You must safeguard against timing problems.
It is very likely that your frame will load completely before the iframe
does.
In that case, you cannot get the OnSelectionChanged method reference.
You can add an "onload" to the iframe, but it is still possible that it will
break, because the internal frames do not load in the expected order.
A simple fix is to wrap your "InitDocument" with a timer.

Also, using the "frames[0].frames[1]" is relying on the order of your page,
and the order of the viewer frames.
A more reliable method, is to use the ID if the frame element, and then use
the built-in method GetMapFrame().

I have applied the above to your example:

<!-- Javascript part -->
<script type="text/javascript">
    var mapFrame = null;   // A reference to the map frame
    var originalMapFrameOnSelectionChanged = null // storage for the
original onSelectionChanged function
    function OnSelectionChanged() // when something is selected on the map
    {
        alert('Your handler works perfectly');
        originalMapFrameOnSelectionChanged();
    }

    function InitDocument()
    {
        var win = document.getElementById('viewerFrame');
        if (win.contentWindow) //FF returns the actual tag, IE returns the
iframe
          win = win.contentWindow;
        mapFrameRef = win.GetMapFrame();
originalMapFrameOnSelectionChanged = mapFrameRef.parent.OnSelectionChanged;
        mapFrameRef.parent.OnSelectionChanged = OnSelectionChanged;

    }   

    function RetryInit()
    {
        if (mapFrame != null)
            return;

        try
        {
            InitDocument();
        }
        catch (e)
        {
            mapFrame = null;
        }

        if (mapFrame == null)
            window.setTimeout("RetryInit();", 500);
    }
</script>

<!-- HTML part -->
<html>
<body>
    <iframe id="viewerFrame" frameborder="yes" width="100%" height="60%"
src="
src="../mapviewernet/dwfviewer.aspx?SESSION=<%=sessionId%>&WEBLAYOUT=<%=webL
ayout%>"" onload="RetryInit()"></iframe>
</body>
</html>

Regards, Kenneth, GEOGRAF A/S

Kimmo Kotajärvi skrev: 

Here’s my solution (simplified):

<!-- Javascript part -->

<script type="text/javascript">

    var mapFrame = null;   // A reference to the map frame

    var originalMapFrameOnSelectionChanged = null // storage for the
original onSelectionChanged function

    function OnSelectionChanged() // when something is selected on the map

    {

        alert('Your handler works perfectly');

        originalMapFrameOnSelectionChanged();

    }

    function InitDocument()

    {

        mapFrameRef = frames[0].frames[1];

originalMapFrameOnSelectionChanged = mapFrameRef.parent.OnSelectionChanged;

        mapFrameRef.parent.OnSelectionChanged = OnSelectionChanged;

    }    

</script>

<!-- HTML part -->

<html>

<body onload= <javascript:InitDocument()> "javascript:InitDocument()">

        <iframe id="viewerFrame" frameborder="yes" width="100%" height="60%"
src="
src="../mapviewernet/dwfviewer.aspx?SESSION=<%=sessionId%>&WEBLAYOUT=<%=webL
ayout%>""></iframe>

</body>

</html>

So, body onload calls InitDocument which registers the new
OnSelectionChanged event handler. The new handler only pops up a dialog box
and then calls the old function. The MG Viewer is embedded in an iframe.

  _____  

Lähettäjä: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] Puolesta Tanja Suikkanen
Lähetetty: 28. huhtikuuta 2008 14:10
Vastaanottaja: mapguide-users at lists.osgeo.org
Aihe: Re: [mapguide-users] OnSelectionChanged in AJAX viewer?

My map is embedded in my own page. 

When a user selects one or more features on the map, I want my own function
to be executed.

But doesn’t parent.parent.mapFrame still get me the map frame..? 

And this works but only when I click some button. 

Tanja

From: Kenneth, GEOGRAF A/S [mailto:ks at geograf.dk] 
Sent: 28. huhtikuuta 2008 13:57
To: tanja.suikkanen at dimenteq.fi; MapGuide Users Mail List
Subject: SPAM-LOW: Re: [mapguide-users] OnSelectionChanged in AJAX viewer?

Are you issuing the script from a command?

If you want to do this all the time (regardless of what the user has done),
you must load the script with the solution.
If your map is embedded in another page, you can load the script there, and
change "var map = parent.parent.mapFrame;" to point to the correct frame.
If it is just the basic layout, you can try to put it in the page that loads
in the taskpane (but beware that the document gets unloaded if the user
navigates).
As a last resort, you can embed the script in the viewerfiles.

In case you can use the embedded map approach, you should place the
following line after the "try {":
map = document.getElementById('<insert iframe/frame id>').GetMapFrame()

Regards, Kenneth, GEOGRAF A/S

Tanja Suikkanen skrev: 

Ok, I sent my code snippet earlier today, but here it is again.

I got this example from
http://trac.osgeo.org/mapguide/wiki/CodeSamples/JavaScript/AJAXViewerEventHo
oking.

var map = parent.parent.mapFrame;

    var origOnSelectionChanged = null;

    function MySelectionHandler()

    {

        origOnSelectionChanged();

        var selCount = map.GetSelectedCount();

        if(selCount > 0)

        {

            My function() {}

        }

    }

    window.onload = function() {

        var timer;

        var watch = function() {

            try {

                if(map.mapInit) {

                    clearInterval(timer);

                    origOnSelectionChanged = map.OnSelectionChanged;

                    map.OnSelectionChanged = MySelectionHandler;

                }

            }

            catch(e) {

            }

        };

        timer = setInterval(watch, 200);

    };

Window.onload function is executed only, if I press a button.

I want to have the functionality I was telling you about without any button
clicks.

Please ask if I don’t tell you enough.

Tanja

From: Ivan Milicevic [mailto:Ivan.Milicevic at supranet.hr] 
Sent: 28. huhtikuuta 2008 12:04
To: tanja.suikkanen at dimenteq.fi; MapGuide Users Mail List
Subject: RE: [mapguide-users] OnSelectionChanged in AJAX viewer?

Feature doesn't get highlighted?

Of course that you can add this functionality  in your own code, the logic
is same. Allwas call mapFrame functions (via JavaScript) or count selection
from C# or PHP.

If you want to get some help over here, be more specific.

Ivan.

From: mapguide-users-bounces at lists.osgeo.org
[mailto:mapguide-users-bounces at lists.osgeo.org] On Behalf Of Tanja Suikkanen
Sent: Monday, April 28, 2008 10:46 AM
To: mapguide-users at lists.osgeo.org
Subject: RE: [mapguide-users] OnSelectionChanged in AJAX viewer?

Ok, now it worked but some functionality had been removed?

When I first select a feature, everything goes fine but when I select
another feature, that doesn’t get highlighted

Also I wouldn’t like to change the original files, just add my own
functionality in my own code files.

But thanks anyway!

Tanja

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