sqlbulkcopy failed to read table

DataTable dt = new DataTable();
           string line = null;
           int i = 0;

           using (StreamReader sr = File.OpenText("C:\\maq\\" + main1.text + "\\" + main1.text + ".txt))
           {
               while ((line = sr.ReadLine()) != null)
               {
                   string[] data = line.Split(',');
                   if (data.Length > 0)
                   {
                       if (i == 0)
                       {
                           foreach (var item in data)
                           {
                               dt.Columns.Add(new DataColumn());
                           }
                           i++;
                       }
                       DataRow row = dt.NewRow();
                       row.ItemArray = data;
                       dt.Rows.Add(row);
                   }
               }
           }

          SqlConnection con = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=c:\maq\" + main1.text + @"\" + main1.text + ".mdf;Trusted_Connection=Yes;User Instance=True;");

               {
               con.Open();
               using (SqlBulkCopy copy = new SqlBulkCopy(con))
               {
                   copy.ColumnMappings.Add(0, 0);
                   copy.ColumnMappings.Add(1, 1);
                   copy.ColumnMappings.Add(2, 2);
                   copy.ColumnMappings.Add(3, 3);
                   copy.ColumnMappings.Add(4, 4);
                   copy.ColumnMappings.Add(5, 5);
                   copy.ColumnMappings.Add(6, 6);
                   copy.DestinationTableName ="marketdetails";
                   copy.WriteToServer(dt);