Microsoft Visual Basic .NET code

ds=ds.Copy()

Microsoft Visual C# .NET code

ds=ds.Copy();

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Steps to reproduce the behavior

1. In Microsoft Visual Studio .NET, create a new Console Application by using either Microsoft Visual Basic .NET or Microsoft Visual C# .NET.
2. Replace the existing code with the following code.

   Visual Basic .NET code

   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
   

   Visual C# .NET code

   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()]);
         }
      }
   }
   

3. In the ConnectionString property of the SqlConnection class, replace YourSQLServer with the name of your SQL Server.
4. On the Debug menu, click Start.
   
   You receive the exception that is mentioned in the "Symptoms" section.

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