[mapguide-users] RE: [Mapguide_users] FW: Remove layers at runtime

[Walt Welton-Lair]

Yeah a missing refresh would make sense.  Isn't it the client's responsibility though to request the refresh?

	-----Original Message----- 
	From: mapguide-users-bounces at lists.osgeo.org on behalf of Trevor Wekel 
	Sent: Mon 1/15/2007 7:12 PM 
	To: Buscher, Shane; Mapguide_users at lists.osgeo.org 
	Cc: 
	Subject: [mapguide-users] RE: [Mapguide_users] FW: Remove layers at runtime
	
	
	Hi Shane,
	 
	Hmm... I wonder if the viewer is not bothering to request the map overlay image again?  That would explain the behaviour you are seeing.
	Are you using a Windows box as a client?  Are you familiar with Fiddler?
	 
	Fiddler is an HTTP proxy that captures HTTP requests and responses.  If you install and use it, you should be able to see all the traffic between the client and Web Extensions / MapAgent.  There should be a GETDYNAMICMAPOVERLAY request generated by the client.  This request should refresh the map and show the added/removed layers.
	 
	Also, are you using Base Map layers (ie. tiled images)?  Base Map layers should not be changed on the fly.  They should be considered static.  This is probably not an issue since you are adding dynamic layers but I just figured I would check.
	 
	Thanks,
	Trevor

  _____  

	From: Buscher, Shane [mailto:Shane.Buscher at nngco.com] 
	Sent: Monday, January 15, 2007 11:04 AM
	To: Trevor Wekel; Mapguide_users at lists.osgeo.org
	Subject: RE: [Mapguide_users] FW: Remove layers at runtime
	
	

	Trevor,

	 

	I think I found a big hint after testing what you suggested.  When the layers I’m trying to remove are within the map view extent, they do not ‘disappear’ upon removing them.  However, If the layers are completely outside the map view extent they indeed get removed with the same code.  It doesn’t matter if it’s one layer or multiples.  Hopefully this gives you something to work with.  

	 

	Regards,

	 

	Shane

	 

	
  _____  


	From: Trevor Wekel [mailto:trevor.wekel at autodesk.com] 
	Sent: Monday, January 15, 2007 11:18 AM
	To: Buscher, Shane; Mapguide_users at lists.osgeo.org
	Subject: RE: [Mapguide_users] FW: Remove layers at runtime

	 

	Hi Shane,

	 

	My bad.  I've been working with the Mapguide 1.1.x and trunk branches.  You are working on the released 1.0.x branch.  Sorry for the confusion.  1.0.x does not have the boolean return.

	 

	Is there any difference if you try to remove only one layer so there are still layers on the map?

	 

	Thanks,

	Trevor

	 

	
  _____  


	From: Buscher, Shane [mailto:Shane.Buscher at nngco.com] 
	Sent: Saturday, January 13, 2007 1:31 PM
	To: Trevor Wekel; Mapguide_users at lists.osgeo.org
	Subject: RE: [Mapguide_users] FW: Remove layers at runtime

	Trevor,

	 

	MgLayerCollection.Remove doesn't return a boolean according to the api documentation, and also doesn't indicate it in the intellisense.  

	 

	Regards,

	 

	Shane

	 

	
  _____  


	From: Trevor Wekel [mailto:trevor.wekel at autodesk.com]
	Sent: Fri 1/12/2007 5:18 PM
	To: Buscher, Shane; Mapguide_users at lists.osgeo.org
	Subject: RE: [Mapguide_users] FW: Remove layers at runtime

	Hi Shane,

	 

	Remove() should returns a boolean true or false.  false indicates that the layer was not removed.  Can you see if the remove was successful? (just trying to debug a bit)

	 

	Thanks,
	Trevor

	 

	
  _____  


	From: Buscher, Shane [mailto:Shane.Buscher at nngco.com] 
	Sent: Friday, January 12, 2007 4:13 PM
	To: Trevor Wekel; Mapguide_users at lists.osgeo.org
	Subject: RE: [Mapguide_users] FW: Remove layers at runtime

	Trevor,

	 

	Thanks for the response.  I think I’m doing everything you suggested correctly, but have provided the snippets below.  When the page loads the ConnectToMapGuide() method gets called, which opens up the MgMap and sets it to a module level variable (map).  Then, Button1 is clicked which successfully adds two layers to the map.  When Button2 gets invoked, I try to remove the layers but the layers still persist in the map.  

	 

	I’m not sure where to go from here.  Do you need to copy the layers in session, then add them from there in order to have the ability to remove them?  Just reaching…

	 

	Regards,

	 

	Shane

	 

	 

	‘class vars

	Private resourceService As MgResourceService

	Private map As MgMap

	 

	Private Sub ConnectToMapGuide()

	        'Connect to MapGuide site

	        Dim userInfo As New MgUserInformation(Session.Item("mgSessionId"))

	        Dim siteConn As New MgSiteConnection

	        siteConn.Open(userInfo)

	 

	        'set resource service

	        resourceService = siteConn.CreateService(MgServiceType.ResourceService)

	 

	        'Open map

	        map = New MgMap

	        map.Open(resourceService, Session.Item("mgMapName"))

	End Sub

	 

	Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click

	        ‘add dwf layer

	   Dim schematicId As NewMgResourceIdentifier _        

	("Library://VST/Layers/SouthOmahaTeamSchematic.LayerDefinition")

	         Dim schematic As MgLayer = CreateLayer(schematicId, False)

	         map.GetLayers.Insert(index, schematic)

	 

	         ‘add sdf layer

	   Dim valveId As New MgResourceIdentifier _ 

	("Library://VST/Layers/SouthOmahaValves.LayerDefinition")

	         Dim valves As MgLayer = CreateLayer(valveId, True)

	         map.GetLayers.Insert(index, valves)

	      

	         map.Save(resourceService)

	 

	        'emit javascript to refresh map

	End Sub

	 

	Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click

	        Dim lyr0 As MgLayer = map.GetLayers.GetItem(0)

	        Dim lyr1 As MgLayer = map.GetLayers.GetItem(1)

	        map.GetLayers.Remove(lyr0)

	        map.GetLayers.Remove(lyr1)

	        map.Save(resourceService)

	 

	        'emit javascript to refresh map

	End Sub

	 

	
  _____  


	From: Trevor Wekel [mailto:trevor.wekel at autodesk.com] 
	Sent: Friday, January 12, 2007 3:37 PM
	To: Buscher, Shane; Mapguide_users at lists.osgeo.org
	Subject: RE: [Mapguide_users] FW: Remove layers at runtime

	 

	Hi Shane,

	 

	This should work.  During your setup, are you calling MgMap.Open() or MgMap.Create()?  The MgMap.Open() should set up the resource identifier correctly so that Save() will have the map to the correct session repository.

	 

	Is the session id being propagated correctly?  If you can do the following and the layer appears in the viewer then the session should be ok.

	 

	MgMap.Open()

	MgMap.GetLayers().Insert(layer)

	MgMap.Save()

	 

	If the Insert() works and Remove() doesn't

	 

	MgMap.Open()

	MgMap.GetLayers().Remove(layer)

	MgMap.Save()

	 

	Then this is probably a bug.  Also, does the behaviour depend on the number remaining layers?

	 

	Thanks,

	Trevor

	 

	 

	
  _____  


	From: Buscher, Shane [mailto:Shane.Buscher at nngco.com] 
	Sent: Friday, January 12, 2007 7:16 AM
	To: Buscher, Shane; Mapguide_users at lists.osgeo.org
	Subject: RE: [Mapguide_users] FW: Remove layers at runtime

	I haven’t got any feedback yet, but I have been trying desperately to make this work.  To recap, I’m finding that adding a layer to a map at runtime with MgLayerCollection.Add works fine.  However, when I try to remove layer(s) with MgLayerCollection.Clear, MgLayerCollection.Remove, or MgLayerCollection.RemoveAt the layer(s) are indeed removed from the collection- but not the map.  I am saving the map and refreshing the map after removal.  

	 

	So why does inserting a layer into the MgMapCollection work, but removing not?  Looking at the developers guide on page 56 there is a note for getting a layer collection from the map (MgMap.GetLayers): 

	 

	In the MapGuide API, getting a collection returns a reference to the collection. So adding the layer to the layer collection immediately updates the map.

	 

	I am get the impression that adding a layer to the collection automatically updates the map, this doesn’t apply for removing a layer.  I can’t figure out what I need to do to mimic what the api does for you when inserting a layer when trying to remove a layer.  Or is this a bug?

	 

	Thanks for any help in advance.  

	 

	Regards,

	 

	Shane

	
  _____  


	From: mapguide_users-bounces at lists.osgeo.org [mailto:mapguide_users-bounces at lists.osgeo.org] On Behalf Of Buscher, Shane
	Sent: Tuesday, January 09, 2007 4:49 PM
	To: Mapguide_users at lists.osgeo.org
	Subject: [Mapguide_users] FW: Remove layers at runtime

	 

	I’ve run into issues with removing all layers from the map at runtime.  See the code snippet below.  All the layers get removed from the layerCollection, but the layers still display.  I’ve successfully used the same code to insert layers, except I execute the layerCollection.Insert(index, layer) method.  I don’t know why the same code wouldn’t work for clearing layers.  

	I have multiple layers stored in a library repository that users need to add and remove at runtime.  Do I need to copy each layer in indvidual session repositories to add and reomove them?  If I don’t, will one user adding/removing layers affect other user sessions?  I know this is the case when you edit data, but these layers are view only.   

	‘Connect to site server, set resource service, and open map

	ConnectToMapGuide()  

	'Clear all layers in the map

	Dim layerCollection As MgLayerCollection = map.GetLayers()

	If layerCollection.GetCount > 0 Then

	  layerCollection.Clear()

	End If

	map.Save(resourceService)

	'emit javascript to refresh map

	Dim scriptKey As String = "ForceRefresh"

	If Not Page.ClientScript.IsStartupScriptRegistered(Me.GetType, scriptKey) Then

	  Dim javaScript As String = "refreshMap(" & MapAction.RefreshMap & ");"

	  Page.ClientScript.RegisterStartupScript(Me.GetType, scriptKey, javaScript, True)

	End If

	Regards,

	Shane

	Operations IT

	Northern Natural Gas

	402.398.7841

	We think in generalities, but live in detail.  

	-Alred North Whitehead

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