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

[Buscher, Shane]

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

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/mapguide-users/attachments/20070113/7290dbdb/attachment-0001.html