请各位帮我看下这段代码运行一直有问题，好像是和数据库连接问题

lxt106297 2009-05-04 09:24:40

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data.Odbc;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace 测试
{
public partial class Form1 :Form
{

public OdbcConnection cn = new OdbcConnection("Dsn=KEVINLXT;Persist Security Info=True;User ID=system;psw=kevin520;");

public Form1()
{
InitializeComponent();
}

private void label1_Click(object sender, EventArgs e)
{

}

private void button1_Click(object sender, EventArgs e)
{
if (textBox1.Text.Trim() == "" || textBox2.Text.Trim() == "")
MessageBox.Show("请输入用户名及密码", "登录失败");
else
{
//cn.Open();
try
{
cn.Open();
}
catch(OdbcException ex)
{
MessageBox.Show(ex.Message);
}

OdbcCommand cmd = new OdbcCommand("", cn);
string oracle = "select * from SCOTT.TEST where 用户名='" + textBox1.Text.Trim() + "' and 密码='" + textBox2.Text.Trim() + "'";
cmd.CommandText = oracle;
string rolename;

if (null != cmd.ExecuteScalar())
{
rolename = cmd.ExecuteScalar().ToString();
this.Visible = false;
Form mainfrm = new Form();
mainfrm.Tag = this.FindForm();
oracle = "select * from role where rolename='" + rolename + "'";
OdbcDataReader dr;
cmd.CommandText = oracle;
dr = cmd.ExecuteReader();
dr.Read();

}
else
MessageBox.Show("用户名或密码错误", "登录失败");
//dr.Close();
cn.Close();
}
}
private void button2_Click(object sender, EventArgs e)
{
this.Close();
}
}
}

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