VB.NET示例app.config访问

任何人都可以提供一个示例代码，演示如何将app.config文件与用VB.NET编写的应用程序集成。具体而言，我需要从app.config文件中提取数据库连接字符串。

请参阅：

Public Shared Function GetConnectionString(ByVal strConnection As String) As String
   'Declare a string to hold the connection string
   Dim sReturn As New String("")
   'Check to see if they provided a connection string name
   If Not String.IsNullOrEmpty(strConnection) Then
      'Retrieve the connection string fromt he app.config
      sReturn = ConfigurationManager. & _
      ConnectionStrings(strConnection).ConnectionString
   Else
      'Since they didnt provide the name of the connection string
       'just grab the default on from app.config
      sReturn = ConfigurationManager. & _
      ConnectionStrings("YourConnectionString").ConnectionString
   End If
   'Return the connection string to the calling method
   Return sReturn
End Function