can not use CsvLayer?

[codeychai]

i downloaded the ArcGIS API 3.1 for Silverlight, and installed it following the steps from esri.

but when i wanted to add a csvlayer, the vs reported that "csvlayer" was not exist in the namespace like below:

错误

1

命名空间“http://schemas.esri.com/arcgis/client/2009”中不存在“CsvLayer”名称。

C:\Users\CODEY\documents\visual studio 2012\Projects\slmapdemo\slmapdemo\MainPage.xaml

22

21

slmapdemo

do anyone can help me? thanks a lot!

[youyuanzhang]

a chinese？