C# datatable 用于二次修改

   MySqlDataReader reader = cmd.ExecuteReader();

 DataTable dt = new DataTable();
 DataTable schemaTable = reader.GetSchemaTable();
 foreach (DataRow dr in schemaTable.Rows)
 {
     DataColumn dc = new DataColumn();
     dc.DataType = dr[0].GetType();
     dc.ColumnName = dr[0].ToString();
     dt.Columns.Add(dc);
 }
 while (reader.Read())
 {
     DataRow row = dt.NewRow();
     for (int i = 0; i < schemaTable.Rows.Count; i++)
     {
         row[i] = reader[i].ToString();
     }
     dt.Rows.Add(row);
     row = null;
 }
 schemaTable.Clear();
 dt.DefaultView.Sort = "land_time ASC";
 dt = dt.DefaultView.ToTable();
foreach (DataRow item in dt.Rows){
 Console.WrintLine(item[0]);
}