ADO.Net总结

在我看来，ADO.Net就这个5个组件；分别是Connection、Parameter、Transaction、Command、DataReader。

            IDbConnection cn = null;
            IDataParameter para = null;
            IDbTransaction tran = null;
            IDbCommand cmd = null;
            IDataReader dr = null;
            try
            {
                cn = new SqlConnection("Data Source=.;Initial Catalog=Northwind;Integrated Security=True");
                if (cn.State == ConnectionState.Closed) cn.Open();

                //tran = cn.BeginTransaction();

                para = new SqlParameter("@Id", SqlDbType.Int, 4);
                para.Value = 1;

                cmd = new SqlCommand();
                cmd.CommandText = "select LastName,FirstName from dbo.Employees where EmployeeID=@Id";
                cmd.CommandTimeout = 150;
                cmd.CommandType = CommandType.Text;
                cmd.Connection = cn;
                cmd.Parameters.Add(para);
                //cmd.Transaction = tran;

                try
                {
                    //cmd.ExecuteNonQuery();
                    //cmd.ExecuteScalar();
                    dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                    while (dr.Read())
                    {
                        Console.WriteLine(dr[0].ToString() + @"\" + dr[1].ToString());
                    }
                    //tran.Commit();
                }
                catch (Exception)
                {
                    //tran.Rollback();
                    throw;
                }
            }
            catch (Exception)
            {
                throw;
            }
            finally
            {

if (cn.State == ConnectionState.Open)
{
　　cn.Close();
　　dr.Close();
}

                if (cn != null) cn.Dispose();
                if (cmd != null) cmd.Dispose();
                if (para != null) para = null;
                if (tran != null) tran.Dispose();
                if (dr != null) dr.Dispose();
            }