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<title>FW: Remove layers at runtime</title>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>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 <i><span style='font-style:italic'>not the map</span></i>. I am
saving the map and refreshing the map after removal. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=navy
face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy'>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): <o:p></o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=navy
face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='text-autospace:none'><i><font size=1 face=StoneSans><span
style='font-size:9.0pt;font-family:StoneSans;font-style:italic'>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.<o:p></o:p></span></font></i></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>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?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Thanks for any help in advance. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Regards,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Shane<o:p></o:p></span></font></p>
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<p class=MsoNormal style='margin-left:.5in'><b><font size=2 face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> mapguide_users-bounces@lists.osgeo.org
[mailto:mapguide_users-bounces@lists.osgeo.org] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Buscher, Shane<br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, January 09, 2007
4:49 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Mapguide_users@lists.osgeo.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [Mapguide_users] FW:
Remove layers at runtime</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal style='margin-left:.5in'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p style='margin-left:.5in'><font size=2 face=Arial><span style='font-size:
10.0pt;font-family:Arial'>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</span></font> <font size=2 face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New"'>layerCollection.Insert(index, layer) method. I
don’t know why the same code wouldn’t work for clearing
layers. </span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>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. </span></font> <o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 face=Arial><span style='font-size:
10.0pt;font-family:Arial'>‘</span></font><font size=2 color=green
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:green'>Connect to site server, set resource service, and open map</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>ConnectToMapGuide() </span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=green face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:green'>'Clear all
layers in the map</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>Dim</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'>
layerCollection</span></font> <font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>As</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'>
MgLayerCollection = map.GetLayers()</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>If</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'>
layerCollection.GetCount > 0</span></font> <font size=2 color=blue
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:blue'>Then</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
layerCollection.Clear()</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>End</span></font>
<font size=2 color=blue face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:blue'>If</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>map.Save(resourceService)</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=green face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:green'>'emit javascript
to refresh map</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>Dim</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'>
scriptKey</span></font> <font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>As</span></font> <font
size=2 color=blue face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:blue'>String</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'> =</span></font> <font
size=2 color=maroon face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:maroon'>"ForceRefresh"</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>If</span></font> <font
size=2 color=blue face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:blue'>Not</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
Page.ClientScript.IsStartupScriptRegistered(<font color=blue><span
style='color:blue'>Me</span></font>.GetType, scriptKey)</span></font> <font
size=2 color=blue face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:blue'>Then</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'> </span></font> <font
size=2 color=blue face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:blue'>Dim</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'> javaScript</span></font> <font
size=2 color=blue face="Courier New"><span style='font-size:10.0pt;font-family:
"Courier New";color:blue'>As</span></font> <font size=2 color=blue
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:blue'>String</span></font><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'> =</span></font> <font
size=2 color=maroon face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:maroon'>"refreshMap("</span></font><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'>
& MapAction.RefreshMap &</span></font> <font size=2 color=maroon
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New";
color:maroon'>");"</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New"'>
Page.ClientScript.RegisterStartupScript(<font color=blue><span
style='color:blue'>Me</span></font>.GetType, scriptKey, javaScript,</span></font>
<font size=2 color=blue face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:blue'>True</span></font><font size=2
face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'>)</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=blue face="Courier New"><span
style='font-size:10.0pt;font-family:"Courier New";color:blue'>End</span></font>
<font size=2 color=blue face="Courier New"><span style='font-size:10.0pt;
font-family:"Courier New";color:blue'>If</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><a name=""><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'>Regards,</span></font></a><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 face=Arial><span style='font-size:
10.0pt;font-family:Arial'>Shane</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=gray face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:gray'>Operations IT</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=gray face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:gray'>Northern Natural Gas</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><font size=2 color=gray face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:gray'>402.398.7841</span></font><o:p></o:p></p>
<p style='margin-left:.5in'><i><font size=2 color=gray face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:gray;font-style:italic'>We
think in generalities, but live in detail. </span></font></i><o:p></o:p></p>
<p style='margin-left:.5in'><i><font size=2 color=gray face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:gray;font-style:italic'>-Alred
North Whitehead</span></font></i><o:p></o:p></p>
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