private void button1_Click(object sender, EventArgs e)
        {
            String name = textBox1.Text;
            String password = textBox2.Text;
            String repassword = textBox3.Text;
            if (password.Equals(repassword) == false)
            {
                MessageBox.Show("两次输入的密码不一致.请重新输入");
            }
            SqlConnection con = new SqlConnection("Data Source=localhost;Initial Catalog=db;Integrated Security=SSPI");
            con.Open();
            SqlCommand com = new SqlCommand("insert into users(username,password)  values('" + textBox1.Text + "','" + textBox2.Text + "')", con);
          
            com.ExecuteNonQuery();
            con.Close();
            MessageBox.Show("恭喜!注册成功!!!");
                    }
提示连接数据库服务器出现的网络错误,怎么弄  急