I am already familiar with Silverlight programming but not have any experience with GIS.
my role as silverlight developer is only to display existing GIS data.
If you guys have any experience with arcGIS silverlight control & api, what else do you think I must learn to be able to use it.
any learning reference could be helpful. thanks.
you don't need alot, you can dl the SDK from ESRI and then check out thier help site they have crap-loads of examples, both downloadable source and live samples (with the source code). If you have a license, you can use bing maps in the ESRI silverlight control--there are assemblies in the SDK for that.
as an aside, the SDK also includes the WPF assemblies as well.
I have made some different projects that used GIS data. I haven't tried arcGIS but used Bing Maps (http://www.bing.com/community/blogs/maps/archive/2009/03/18/introducing-the-virtual-earth-silverlight-map-control.aspx) and a Silverlight component from ThinkGeo (http://gis.thinkgeo.com/Microsite1/MapSuiteSilverlight2/tabid/709/Default.aspx?adcampaign=Map+Suite+Silverlight+Edition&leadsource=Google&adgroup=Silverlight+General&adtype=search&keyword=silverlight+map&gclid=CIu976aW0Z0CFZ1h4wodwGsDsA).
I think that Bing Maps is really easy to work with and there is lots of help available online. Maybe that can help you with some starting resources to argGIS?!
Chris is right. The help site has enough samples. I don't have Silverlight skills, so I really struggled with it and I was pretty bad at it too. I think the silverlight learning curve is much steeper.
I tried to wire up GIS tools/buttons to a ribbon control. It sort of worked, a silverlight dev would do a better job: View esri-silverlight-toc-png
If you just need to control visibility, between services. It's real easy. Or if you have one service, with layers inside that you need to control...that's easy too.
But if you need both, you will have to roll your own layer control. I wired it up to a treeview, but it doesn't look sexy. ESRI may have a better TableofContents control out now, they didn't when I was messing with it: View esri-silverlight-png
It helps to have a basic understaind of the ESRI Map and Graphics object model for any of their API's (they all have similarities). The Silverlight API is much simpler than the Arcobjects API, but shares many of the same patterns.
If you are performing specific operations (such as distance calculations, map annotating, etc) there may be very specific concepts that will help. Can you post a question with more details about your goal?