DataReader

DataReader

 

dr.HasRows;判断是否有一行，多行
dr.NextResult();读取下一个表
dr.Read();读取当前行，并移到下一行
dr[i],dr.GetValue(i)  两种用法得到的结果一样,一般用第一种方法 
dr.IsDBNull(i);判断当前行的i+1列是否有值  这个属性一般用，用了反而在布局方面有影响
dr.GetName(i);获取当前行该列＋1的字段名称
dr.FieldCount;当前行有多少列

当要执行多个表时，要加上CommandBehavior.CloseConnection

 using (SqlCommand cmd = new SqlCommand())
            {
                cmd.Connection = conn;
                cmd.CommandText = "select *  from admin where id=@id;select * from company where id=6";
                cmd.Parameters.AddWithValue("@id", TextBox1.Text);
                SqlDataReader dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                if (dr.HasRows)
                {
                    do
                    {
                        if (dr.Read())
                        {
                            // dr.HasRows; dr.Read(); dr.NextResult; dr.IsDBNull; dr.GetName(i); dr.FieldCount;
                            if(!dr.IsDBNull(0))
                            Response.Write(dr[0]);
                        }
                    } while (dr.NextResult());
                }
                   
                   
            }