[mapguide-users] Re: Is it possible to modify scale ranges of a layer dynamically
Do you need the scale ranges only for showing the layer in the map or do you want to save this scale ranges to the layer definition? Regards, Johannes Foell SriRam007 wrote: Hi everyone, Can anyone please tell me Is it possible to modify scale ranges of a layer dynamically using MGOS and C#.net thanks -- View this message in context: http://n2.nabble.com/Is-it-possible-to-modify-scale-ranges-of-a-layer-dynamically-tp4631747p4631777.html Sent from the MapGuide Users mailing list archive at Nabble.com. ___ mapguide-users mailing list mapguide-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapguide-users
[mapguide-users] Re: Getting layer's maxscale to Viewer API
Thank you Kenneth for your great help.
I've solved it with the public variable.
Best regards,
Johannes Foell
Kenneth Skovhede, GEOGRAF A/S wrote:
Performance of codebehind is much better, and so is the general
dependency etc. If at all possible, I recommend that you use codebehind.
Also, when writing ajax handlers, be sure to use .ashx as they have less
overhead than
the .aspx pages.
In your code (regardless of where it is placed), you can either
use the public variable approach I outlined, or use the response.write
method to write data to the output stream.
Try to install and use FireBug (for FireFox) or Fiddler (for IE),
with either tool, you can see the data being transfered, and that should
help you understand what data you are transmitting.
I'm not sure why you use the JavaScripSerializer, as you already have
the string in a JSON format?
The value should not be enclosed in strings, eg, it should be:
Dim MString as String = {scale:
MaxSC.ToString(System.Globalization.CultureInfo.InvariantCulture) }
Then:
Response.Clear()
Response.Write(MString)
Response.Flush()
Response.End()
In the JS code, you attempt to do something directly after you issue the
AJAX call.
Since AJAX is async you do not yet have the data.
You must wait for the data to be fetched from the server, which is what
the
onreadystatechanged function is for.
Inside this function, you unwrap the JSON string into a javascript
object.
Your maxsc2 variable is the object, so you can call:
var scale = maxsc2.scale; //Your code names the variable double, eg:
var scale = maxsc2.double;
parent.KartenFrame.viewerFrame.mapFrame.ZoomToView(xcoord,ycoord,scale,true);
Remember that the code after request.send() gets executed immediately, and
does NOT wait for the server to finish processing.
You must do all the processing inside the onreadystatechanged function.
Once the data is returned, you can call the zoom function, but not before.
I recommend that you also send the x/y values back and forth, so you can
easily access them
inside the onreadystatechanged callback. Otherwise you need to worry
about function scopes
and javascript enclosures (advanced JS topic).
I recomend that you use some JS framework to achieve this, as that will
handle function scope better than the raw method you use here.
A JS framework will also give you a nice error handler, and will be
cross browser.
Prototype seems to be popular:
http://www.prototypejs.org/api/ajax/request
It's ajax request object has onSuccess and onFailure, so
you can give the user a nice message if the server fails, or the network
link breaks.
Regards, Kenneth Skovhede, GEOGRAF A/S
On 18-02-2010 15:57, Johannes Foell wrote:
You have exactly pointed out what i need.
Unfortunately I'm using code inline and not codebehind. The first way,
which
you presented doesn't work in my code.
As newbie to JSON i've tested your second solution, but i do'nt get the
scale to the client there, too.
Does anyone here knows, how to deliver a JSON-object from the server to
the
client? What is wrong in my code?
The important lines are:
In VB.NET:
Sub reload (ByVal o As Object, ByVal e As EventArgs)
MaxSc is the double-variable, which contains the MaxScale for the
Layer.
Dim MString As String = { + Chr(34) + double + Chr(34) + : +
Chr(34)
+ MaxSc.ToString + Chr(34) + } ' e.g. the JSON-Object:
{double:31456.57}
Dim serializer As New JavaScriptSerializer
Dim json As String = serializer.Serialize(MString)
End Sub
In JS:
function ZoomToView()
{
var url; //the current aspx-file
var maxsc;
var maxsc2;
try {
var request = new XMLHttpRequest();
} catch(ex) {
try {
var request = new ActiveXObject(MSXML2.XMLHTTP);
} catch (ex) {
var request = new ActiveXObject(Microsoft.XMLHTTP);
}
}
request.onreadystatechange = function() {
if(request.readyState == 4) {
maxsc2 = eval(( + request.responseText + )); //what do i have to
call
here?
}
}
request.open(GET, url, true);
request.send();
maxsc = maxsc2.double; //the double-field of the object
maxsc -= 0.1; //to show the layer in the map
parent.KartenFrame.viewerFrame.mapFrame.ZoomToView(xcoord,ycoord,maxsc,true);
//the coordinates are no problem. if i set here a number as maxsc, e.g.
15000, it works
}
Thanks for any help.
Regards,
Johannes Foell
Kenneth Skovhede, GEOGRAF A/S wrote:
Not sure this is what you are asking but, this is how I understand your
question.
Basically the output of an ASPX page is html (or any format really).
Since you want to output the scale, you would want the following html
output:
htmlbodyscript
var maxScale =%=serverGeneratedMaxScale%;
GetMap().ZoomToView(x, y, maxScale);
/script/body/html
(I've left out the GetMap() and x, y code).
The%=serverGeneratedMaxScale% gets processed by the ASP.Net runtime,
and inserts the value of the variable named
[mapguide-users] Re: Getting layer's maxscale to Viewer API
You have exactly pointed out what i need.
Unfortunately I'm using code inline and not codebehind. The first way, which
you presented doesn't work in my code.
As newbie to JSON i've tested your second solution, but i do'nt get the
scale to the client there, too.
Does anyone here knows, how to deliver a JSON-object from the server to the
client? What is wrong in my code?
The important lines are:
In VB.NET:
Sub reload (ByVal o As Object, ByVal e As EventArgs)
MaxSc is the double-variable, which contains the MaxScale for the Layer.
Dim MString As String = { + Chr(34) + double + Chr(34) + : + Chr(34)
+ MaxSc.ToString + Chr(34) + } ' e.g. the JSON-Object:
{double:31456.57}
Dim serializer As New JavaScriptSerializer
Dim json As String = serializer.Serialize(MString)
End Sub
In JS:
function ZoomToView()
{
var url; //the current aspx-file
var maxsc;
var maxsc2;
try {
var request = new XMLHttpRequest();
} catch(ex) {
try {
var request = new ActiveXObject(MSXML2.XMLHTTP);
} catch (ex) {
var request = new ActiveXObject(Microsoft.XMLHTTP);
}
}
request.onreadystatechange = function() {
if(request.readyState == 4) {
maxsc2 = eval(( + request.responseText + )); //what do i have to call
here?
}
}
request.open(GET, url, true);
request.send();
maxsc = maxsc2.double; //the double-field of the object
maxsc -= 0.1; //to show the layer in the map
parent.KartenFrame.viewerFrame.mapFrame.ZoomToView(xcoord,ycoord,maxsc,true);
//the coordinates are no problem. if i set here a number as maxsc, e.g.
15000, it works
}
Thanks for any help.
Regards,
Johannes Foell
Kenneth Skovhede, GEOGRAF A/S wrote:
Not sure this is what you are asking but, this is how I understand your
question.
Basically the output of an ASPX page is html (or any format really).
Since you want to output the scale, you would want the following html
output:
htmlbodyscript
var maxScale = %=serverGeneratedMaxScale%;
GetMap().ZoomToView(x, y, maxScale);
/script/body/html
(I've left out the GetMap() and x, y code).
The %=serverGeneratedMaxScale% gets processed by the ASP.Net runtime,
and inserts the value of the variable named serverGeneratedMaxScale in
th output.
In your codebehind file, just declare a public instance variable with
that name,
and insert the above code in the aspx (below the codebehind declaration),
and it should come out.
Another slightly more sophisticated way of doing this, is to issue and
AJAX call
and have the page return a JSON object string like:
{x: 333, y: 444, maxScale: 555}
Then in your Ajax callback handler do this:
var obj = eval('(' + responseText + ')');
GetMap().ZoomToView(obj.x, obj.y, obj.maxScale);
I can't remember what the AJAX stuff is called in the viewer, but there
are
plenty of free AJAX helper code avalible online.
The benefit of using an AJAX call is that the user cannot pres back,
there is no click sound, and you don't need to mess with hidden frames.
Regards, Kenneth Skovhede, GEOGRAF A/S
On 15-02-2010 16:25, Johannes Foell wrote:
Hi List,
I'm new to MG (and JS) and have a question about the layer's maxscale. I
can
read the maxscale out of the Layerdefinition using a XML-File. Having the
maxscale read out for each layer, I need the highest maximum for the
layergroup at the Viewer API to zoom to a given coordinate and this
maxscale.
Currently i compare the different maxscales and save the largest number
as
double. Writing this double to a new XML-File, i can't read it to the
Viewer
API.
Is there a way to get this maxscale to the Viewer API and the method
ZoomToView()?
I'm using VB.Net and JS.
Or is there just another solution?
Thanks for any hint in advance.
Best regards,
Johannes Foell
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[mapguide-users] Getting layer's maxscale to Viewer API
Hi List, I'm new to MG (and JS) and have a question about the layer's maxscale. I can read the maxscale out of the Layerdefinition using a XML-File. Having the maxscale read out for each layer, I need the highest maximum for the layergroup at the Viewer API to zoom to a given coordinate and this maxscale. Currently i compare the different maxscales and save the largest number as double. Writing this double to a new XML-File, i can't read it to the Viewer API. Is there a way to get this maxscale to the Viewer API and the method ZoomToView()? I'm using VB.Net and JS. Or is there just another solution? Thanks for any hint in advance. Best regards, Johannes Foell -- View this message in context: http://n2.nabble.com/Getting-layer-s-maxscale-to-Viewer-API-tp4575036p4575036.html Sent from the MapGuide Users mailing list archive at Nabble.com. ___ mapguide-users mailing list mapguide-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapguide-users
[mapguide-users] Re: Change map scale or get min and max scale from layer
I've solved the same problem to gain the ScaleRanges for Visability with the given solution. Unfortunately, I need the current scale to set the Layer shown in an outsourced Legend. Is there a way to achieve the current scale? The method GetViewScale() gives 1.0 to me, too. Thanks for help in advance. Kind regards, Johannes Foell -- View this message in context: http://n2.nabble.com/Change-map-scale-or-get-min-and-max-scale-from-layer-tp1817851p4540806.html Sent from the MapGuide Users mailing list archive at Nabble.com. ___ mapguide-users mailing list mapguide-users@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/mapguide-users
