private void textBox1_KeyDown(object sender, KeyEventArgs e)

        {
            string con_net = "Data Source=190.190.169.41;User ID=sa;Password=sa;Initial Catalog=DDP-MES-DATA;";
            string sql_nec = "SELECT  [IMEI],[MTK_IMEI],[SN] FROM [041101014 IMEI]WHERE [IMEI]=" + "'" + textBox1.Text.Trim() + "'or [MTK_IMEI]=" + "'" + textBox1.Text.Trim() + "'or [SN]=" + "'" + textBox1.Text.Trim() + "'";
            
            
            DataTable dt_nc = new DataTable();
            SqlDataAdapter da_nc = new SqlDataAdapter(sql_nec, con_net);
            da_nc.Fill(dt_nc);
           
            if (e.KeyCode == Keys.Enter)
            {

            

                if (dt_nc.Rows.Count == 0 )
                {
                    Form2 fm2 = new Form2();
                fm2.ShowDialog();
                    
                    textBox1.Text = "";
                }
                else
                {
                    textBox2.Focus();
                    
                }
 private void textBox2_KeyDown(object sender, KeyEventArgs e)
        {
           
            string con_neg = "Data Source=190.190.169.41;User ID=sa;Password=sa;Initial Catalog=DDP-MES-DATA;";
            string sql_neg = "SELECT COUNT(*) FROM [041101014 IMEI] WHERE [IMEI]=" + "'" + textBox1.Text.Trim() + "' and [SN]=" + "'" + textBox2.Text.Trim() + "'or[IMEI]=" + "'" + textBox1.Text.Trim() + "' and[MTK_IMEI]=" + "'" + textBox2.Text.Trim() + "'or[SN]=" + "'" + textBox1.Text.Trim() + "' and[IMEI]=" + "'" + textBox2.Text.Trim() + "'or[SN]=" + "'" + textBox1.Text.Trim() + "' and[MTK_IMEI]=" + "'" + textBox2.Text.Trim() + "'or[MTK_IMEI]=" + "'" + textBox1.Text.Trim() + "' and[SN]=" + "'" + textBox2.Text.Trim() + "'or[MTK_IMEI]=" + "'" + textBox1.Text.Trim() + "' and[IMEI]=" + "'" + textBox2.Text.Trim() + "'";
            //这个是我连接的表
            DataTable dt_ng = new DataTable();
            SqlDataAdapter da_ng = new SqlDataAdapter(sql_nef, con_neg);
            da_ng.Fill(dt_ng);

            for (int j = 0; j < dt_PO.Rows.Count; j++)

            if (e.KeyCode == Keys.Enter)
            {
      
            
            if (dt_ng.Rows.Count == 0)//到这不执行了，没有达到我判定的效果，这是因为什么。我现在是分别在textbox1和textbox2中输入两个数字，看是不是在同一行，我判定是在textbox2下判定的
            {
                textBox1.Text = "";
                textBox2.Text = "";
                Form2 fm2 = new Form2();
                fm2.ShowDialog();
                System.Media.SoundPlayer sndPlayer = new
            System.Media.SoundPlayer(Application.StartupPath + @"/bad.wav");
                sndPlayer.Play();
            }
            else
               
            {
               
                textBox1.Text = "";
                textBox2.Text = "";
                textBox1.Focus();
               

            }
这段代码意思是，我有textbox1和textbox2，首先我先输入一个数字，如果数据库里有个数，就正常执行，否知出错，如果第一个数字是正确的，然后输入在textbox2输入第二个数字，如果第二个数字和第一个数字他们是处于数据库里的同一行，那么就正常执行，否则显示出错。

有没有人啊~~~~

求帮助，我学编程没到一个来月，基本功很不扎实，但是领导要让我编程序，现在就剩这个关键部分，把这个解决了，我的程序就全部完事了，求指导，有木有狠人啊！！

可以写个存储过程在服务器上判断根据返回值在程序里面控制

if (dt_ng.Rows.Count == 0) 改为 ： if (dt_ng.Rows[0][0].ToString() == "0")

牛逼，一眼就看出我的错误在哪了，太感谢了，但是能不能给我解释下dt_nd.Rows[0][0].ToString() == "0"的意思呢，谢谢了。。

dt_ng.Rows.Count 是你查询语句的行数，如果 Select Count(*) ... 能正确查询，dt_ng.Rows.Count 就肯定=1；dt_nd.Rows[0][0].ToString()是你查询语句结果的第一行第一列的数据

哦，明白了，谢谢了，对我帮助很大啊