这个问题（C#+SQL）是怎么搞的？

[jxjjljf]

編譯器錯誤訊息: CS0246: 找不到型別或命名空間名稱 'myCommand' (您是否遺漏 using 指示詞或組件參考?)
行 153: myCommand.Connection.Open();


OleDbConnection myConnection = new OleDbConnection("provider=sqloledb.1;datasource=(local);uid=sa;pwd=123456;initial catalog=pubs");
OleDbCommand c = new OleDbCommand();
c.CommandText = "insert into qa(kehu,zhidanhao,caigoudanhao,gongyingshang,dingdan_name,piliang_num,yangben_num,MA11,MI11,MA22,MI22,caizhi,tanxing,guige,zhanxing,yanse,duma,waiguan,yinshua,yingdu,qita)values('" + kehu.Text.ToString() + "', '" + zhidanhao.Text.ToString() + "','" + caigoudanhao.Text.ToString() + "','" + gongyingshang.Text.ToString() + "', '" + dingdan_name.Text.ToString() + "','" + piliang_num.Text.ToString() + "','" + yangben_num.Text.ToString() + "','" + MA11.Text.ToString() + "','" + MI11.Text.ToString() + "','" + MA22.Text.ToString() + "', '" + MI22.Text.ToString() + "','" + caizhi.Text.ToString() + "','" + tanxing.Text.ToString() + "', '" + guige.Text.ToString() + "','" + zhanxing.Text.ToString() + "','" + yanse.Text.ToString() + "','" + duma.Text.ToString() + "','" + waiguan.Text.ToString() + "','" + yinshua.Text.ToString() + "', '" + yingdu.Text.ToString() + "','" + qita.Text.ToString() + "')";

myCommand.Connection.Open();
myCommand.ExecuteNonQuery();
myCommand.Connection.Close();

[Night_Elf]

在文件的最顶部写上：
using system.data
using system.data.sqlclient

[jxjjljf]

少了这个吧？
, myConnection);

[jxjjljf]

c.CommandText 换成 myCommand.CommandText

[stcllnb]

应该在文件的最顶部写上：
using system.data；
using system.data.OleDb；

[jxjjljf]

using System;
using System.Data.SqlClient;
using System.Data;
using System.Data.OleDb;
using System.IO;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
都写了啊，还是：
例外詳細資訊: System.NullReferenceException: 並未將物件參考設定為物件的執行個體
行 155: myCommand.Connection.Open();