Module Module1

    Sub Main()
      Dim cn As New SqlClient.SqlConnection()
      'Connect to SQLServer. 
      cn.ConnectionString = "data source=YourSQLServer;integrated security=SSPI;persist security info=False;initial catalog=Northwind"
      Dim da As New SqlClient.SqlDataAdapter("select * from products", cn)
      Dim ds As New DataSet()
      da.Fill(ds, "Products")

      Dim colname As String
      colname = ds.Tables(0).Columns(0).ColumnName

      'Display the data in the first column of the first row.
      Console.WriteLine(ds.Tables(0).Rows(0)(colname.ToLower()))
      Console.ReadLine()

      'Change the column names.
      Dim i As Integer
      For i = 0 To ds.Tables(0).Columns.Count - 1
         ds.Tables(0).Columns(i).ColumnName = "C" & i.ToString()
      Next

      'Display the data in the first column of the first row .
      colname = ds.Tables(0).Columns(0).ColumnName
      Console.WriteLine(ds.Tables(0).Rows(0)(colname.ToLower()))
      Console.ReadLine()

    End Sub

End Module

using System;
using System.Data.SqlClient;
using System.Data;

namespace ConsoleApplication1
{
   class Class1
   {
      [STAThread]
      static void Main(string[] args)
      { 
         SqlConnection cn;
         //Connect to SQLServer.
         cn = new SqlConnection();
         cn.ConnectionString = "data source=YourSQLServer;integrated security=SSPI;persist security info=False;initial catalog=Northwind";
        
         SqlDataAdapter da;
         da = new SqlDataAdapter("select * from products", cn);
          
         DataSet ds;
         ds = new DataSet();

         da.Fill(ds, "Products");

         String colname;
         colname = ds.Tables[0].Columns[0].ColumnName;

        //Display the data in the the first row of the first column.
         Console.WriteLine(ds.Tables[0].Rows[0][colname.ToLower()]);
         Console.ReadLine();

         //Change the column names.
         int i;
         for (i =0;i<= (ds.Tables[0].Columns.Count - 1);i=i+1)
            ds.Tables[0].Columns[i].ColumnName = "C" + i.ToString();
             
         colname = ds.Tables[0].Columns[0].ColumnName;
         //display the data in the first row of the first column           
         Console.WriteLine(ds.Tables[0].Rows[0][colname.ToLower()]);
      }
   }
}