I have the need to highlight items when the user selects to zoom to a particular item from a custom search. If I was using the ResultsTask control, then the user could simply check the checkbox next to the feature, and it would highlight. However, since the client doesn't like the treeview style of the ResultsTask, I have put the search results into an HTML table. Now, when the user selects to zoom to a feature, it will automatically highlight the feature.
I found this code in the ESRI forums, and it works well.
// This gives us a nice light blue color. You can change the color to whatever you want.
ESRI.ArcGIS.ADF.ArcGISServer.RgbColor irgbc = new ESRI.ArcGIS.ADF.ArcGISServer.RgbColor();
irgbc.Red = 50;
irgbc.Green = 255;
irgbc.Blue = 255;
irgbc.AlphaValue = 255;
ESRI.ArcGIS.ADF.ArcGISServer.FIDSet fids = new ESRI.ArcGIS.ADF.ArcGISServer.FIDSet();
int[] ids = new int[1];
ids[0] = Convert.ToInt32(key); //<-- OBJECTID of the feature to highlight
fids.FIDArray = ids;
ESRI.ArcGIS.ADF.ArcGISServer.MapDescription mapdesc = ((MapFunctionality)mf).MapDescription;
ESRI.ArcGIS.ADF.ArcGISServer.LayerDescription[] layerdescs = mapdesc.LayerDescriptions;
ESRI.ArcGIS.ADF.ArcGISServer.LayerDescription layerdesc = layerdescs[layerid];
layerdesc.Visible = true;
layerdesc.SelectionColor = irgbc;
layerdesc.SelectionFeatures = fids.FIDArray;
The problem with the above code is that it highlights the entire area. Not bad for point features, but for polygons, it covers everything underneath it completely. I tried adjusting the RgbColor.AlphaValue, but that didn't change anything at all. I'm thinking that is a red herring, and doesn't really do anything at all. So what I decided to do was instead of filling the entire polygon, I just use ShowSelectBuffer as seen below:
ESRI.ArcGIS.ADF.ArcGISServer.RgbColor irgbc = new ESRI.ArcGIS.ADF.ArcGISServer.RgbColor();
irgbc.Red = 50;
irgbc.Green = 255;
irgbc.Blue = 255;
irgbc.AlphaValue = 255;
ESRI.ArcGIS.ADF.ArcGISServer.FIDSet fids = new ESRI.ArcGIS.ADF.ArcGISServer.FIDSet();
int[] ids = new int[1];
ids[0] = Convert.ToInt32(key);
fids.FIDArray = ids;
ESRI.ArcGIS.ADF.ArcGISServer.MapDescription mapdesc = ((MapFunctionality)mf).MapDescription;
ESRI.ArcGIS.ADF.ArcGISServer.LayerDescription[] layerdescs = mapdesc.LayerDescriptions;
ESRI.ArcGIS.ADF.ArcGISServer.LayerDescription layerdesc = layerdescs[layerid];
layerdesc.Visible = true;
layerdesc.ShowSelectionBuffer = true;
layerdesc.SelectionFeatures = fids.FIDArray;
By using LayerDescription.ShowSelectBuffer, the feature is outlined with the highligh color, instead of filled in. This gives us the ability to see what is within the feature, while still knowing where the feature was located.
References:
http://forums.esri.com/Thread.asp?c=158&f=2276&t=211190&mc=12#msgid719661
http://forums.esri.com/Thread.asp?c=158&f=2276&t=223224&mc=1
6 comments:
Hello,
do you know if it's possible to highlight different features of the same layer using different colors simultaneously?
thanks,
claudia
Hmmm...good question. It *should* be. I know we were doing this for a desktop app we had, but that is desktop, and this isn't. However, you should be able to create graphics layers for each feature subset you want, and assign different symbols and colors to each one. It would kind of act like an overlay. I need to write up a post on doing graphic layers (since that is something I have recently been playing with).
Thanks a lot for your post. I was in big mess ... your code helped a lot :-)
Hi, do you know if its possible to set an image (pin) to the selected symbol of the layerdescription?
Thanks in advance
thnx mate it ws very helpfull
Thanks much. This code is very helpful.
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