VB2008 不是configuration的成员,该怎么解决

VB2008 不是configuration的成员
Imports System.Data
Imports System.Data.SqlClient
Imports System.IO
Public Class DBclass
  Private connectingstring As String
  Private myConn As SqlConnection
  Private ds As DataSet
  Private myAdapter As SqlDataAdapter
  Private myCmd As SqlCommand
  Public Sub New()
  connectingstring = System.Configuration.ConfigurationManager.connectionStrings("cen_study-connectionString").connectionString
  myConn = New SqlConnection(connectingstring)
  End Sub

End Class
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上边一段程序，总是提示我ConfigurationManager不是Configuration的成员，请问怎么解决?


------解决方案--------------------
先
Imports System.Configuration.ConfigurationManager
代码中:
myConn = New SqlConnection(ConnectionStrings("cen_study-connectionString").ToString()) 

------解决方案--------------------
上面是VS2005的写法, VS2008建议具体查一下MSDN....