using System;
using System.Collections.Generic;
using
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
using System.Reflection;


namespace DP_Capability
{
    public partial class Login : Form
    {
        
        public Login()
        {
            InitializeComponent();
        }

        private void Login_Activated(object sender, EventArgs e)
        {
            textBox1.Focus();
        }
        
        private void button2_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar == '\r')
                textBox2.Focus();
        }

        private void textBox2_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar == '\r')
                button1.Focus();
        }
      
        private void button1_Click(object sender, EventArgs e)
        {
            //字符串赋值：用户名和密码
            string username = textBox1.Text.Trim();
            string userpwd = textBox2.Text.Trim();

            //定义数据库连接语句
            string consqlserver = "Data Source=.;Initial Catalog=DP Capability;Integrated Security=True;";

            //定义SQL查询语句：用户名和密码
            string sql = "select * from login where uid='" + username + "' and pwd='" + userpwd + "' ";

            //定义SQL Server连接对象 打开数据库
            SqlConnection Connection = new SqlConnection(consqlserver);
            Connection.Open();

            //定义查询命令:表示对数据库执行一个SQL语句或存储过程
            SqlCommand com = new SqlCommand(sql, Connection);

            //执行查询:提供一种读取数据库行的方式   
            SqlDataReader sread = com.ExecuteReader();
            try
            {

                //如果存在用户名和密码正确数据执行进入系统操作  
                if (sread.Read())
                {
                    //MessageBox.Show("登录成功");
                    this.Close();
                    NavalModel NM = new NavalModel();
                    NM.Show();
                }
                else
                {
                    MessageBox.Show("请输入正确的用户名和密码");
                }
            }

            catch (Exception msg)
            {

                throw new Exception(msg.ToString());  //处理异常信息
            }
            finally
            {
                Connection.Close();                    //关闭连接
                Connection.Dispose();                  //释放连接  
                sread.Dispose();                //释放资源
            }
        }
     }
}

我们用的数据库不一样

是代码出问题了还是数据库链接不上了？ 如果是2005首先链接字符串呃实例就不对