Dim instance As XmlServer

public class XmlServer : xmldanet.xmlda.OpcXmlDA 

string srvUrl = "http://tswinc.us/XMLDADemo/ts_sim/OpcDaGateway.asmx";

      private void Browse_Click(object sender, System.EventArgs e)
      {
         XmlServer Srv = new XmlServer( srvUrl );
         try
         {
            //------------ Get the current server status
            ServerStatus status ;
            Srv.GetStatus( null, null, out status );

            //------------ browse the server into a TreeNode structure
            OPCError[] err ;
            TreeNode[] tn = Srv.BrowseTree( null, null, false, null, true, true, out err );
         }
         catch( Exception ex )
         {
            MessageBox.Show( ex.Message, "Error at Browse" );
         }
      }

Dim srvUrl As String = "http://tswinc.us/XMLDADemo/ts_sim/OpcDaGateway.asmx"

   Private Sub Browse_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Browse.Click
      Dim Srv As XmlServer = New XmlServer(srvUrl)
      Try
         '------------ Get the current server status
         Dim status As ServerStatus
         Srv.GetStatus(Nothing, Nothing, status)

         '------------ browse the server into a TreeNode structure
         Dim err As OPCError()
         Dim tn As TreeNode() = Srv.BrowseTree(Nothing, Nothing, False, Nothing, True, True, err)
      Catch ex As Exception
         MessageBox.Show(ex.Message, "Error at Browse")
      End Try
   End Sub