问个记住密码的问题

Question

登陆窗体做成像qq那样的能记住密码的功能，现在数据库里面的管理员密码采用的是md5加密算法，管理员表有四个字段：id,name ,password,status,其中status是记住checkbox复选框是否被选中('真'或'假')。现在的问题是：如果数据库的密码字段不用md5加密，能够实现，但是如果加密就读不出来了，请大家帮帮忙啊！以下是关键代码：
private void LoginForm_Load(object sender, EventArgs e)
        {
            string path = "login.bin";
            if (!File.Exists(path))
            {
                return;
            }
            FileStream fs = new FileStream(path, FileMode.Open);
            BinaryFormatter bf = new BinaryFormatter();
            list = (List<Login>)bf.Deserialize(fs);
            foreach (Login login in list)
            {
                this.comboBox1.Items.Add(login.Uid);
            }
            fs.Close();
            if (this.comboBox1.Items.Count > 0)
            {
                this.comboBox1.SelectedIndex = 0;
            }
            ReFill();//填充密码记住密码复选框
        }
 private void ReFill()//填充密码文本框
        {
            string pwd = "";
            string status = "";
            string sql = "select password,status from Admin where name='" + this.comboBox1.Text + "'";
            Con = new SqlConnection(strCon);
            Con.Open();
            SqlCommand sqlComm = new SqlCommand(sql, Con);
            SqlDataReader sqlDR = sqlComm.ExecuteReader();
            if (sqlDR.Read())
            {
                pwd = sqlDR[0].ToString();
                status = sqlDR[1].ToString();
            }
            Con.Close();
            if (status == "真")
            {
                this.checkBox1.Checked = true;
                this.textBox1.Text = pwd;
            }
            else
            {
                this.checkBox1.Checked = false;
                this.textBox1.Text = "";
            }
        }
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)//checkbox
        {
            this.ReFill();
        }
//登陆按钮代码
private void button1_Click(object sender, EventArgs e)
        {
            string strSelect = "select count(*) from Admin where name='"+this.comboBox1.Text+"' and password='"+this.textBox1.Text+"'";
            Con = new SqlConnection(strCon);
            try
            {
                Con.Open();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            SqlCommand sqlComm = new SqlCommand(strSelect,Con);
            try
            {
                if ((int)sqlComm.ExecuteScalar() == 1)
                {
                    this.Hide();
                    MainForm mf = new MainForm();
                    mf.ShowDialog();                    string path = "login.bin";                    if (!File.Exists(path))
                    {
                        FileStream fs = new FileStream(path, FileMode.Create);
                        BinaryFormatter bf = new BinaryFormatter();
                        Login login = new Login();
                        login.Uid = this.comboBox1.Text;
                        list.Add(login);
                        bf.Serialize(fs, list);
                        fs.Close();
                    }
                    else
                    {
                        FileStream fs = new FileStream(path, FileMode.Open);
                        BinaryFormatter bf = new BinaryFormatter();
                        list = (List<Login>)bf.Deserialize(fs);
                        bool f = true;
                        foreach (Login login in list)
                        {
                            if (login.Uid == this.comboBox1.Text)
                            {
                                f = true; break;
                            }
                            else
                            {
                                f = false;
                            }
                        }
                        fs.Close();
                        if (f == false)
                        {
                            fs = new FileStream(path, FileMode.Create);
                            bf = new BinaryFormatter();
                            Login login = new Login(); 
                            login.Uid = this.comboBox1.Text;
                            list.Add(login);
                            bf.Serialize(fs, list);
                            fs.Close();
                        }
                    }
                                       string chk = this.checkBox1.Checked == true ? "真" : "假";
                    string strSel1 = "update Admin set status='" + chk + "' where name='" + this.comboBox1.Text + "' and password='" + this.textBox1.Text + "'"; ;
                    this.Close();
                    SqlCommand sqlComm1 = new SqlCommand(strSel1, Con);
                    sqlComm1.ExecuteNonQuery();//修改复选框的值
                    Con.Close();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

Answer 1

中间设置一个string str保存密码    
if (status == "真")
  {
  this.checkBox1.Checked = true;
  this.textBox1.Text = pwd;
  str=pwd
  }
//登陆按钮代码
if (str!="") str=this.textBox1.Text ；
else str=MD5(this.textBox1.Text )；
当然  如果变换comboBox1的SelectIndex时重新根据保存密码项设置str的值
这样就可以MD5了

Answer 2

//登陆按钮代码
if (str=="")  str=MD5(this.textBox1.Text )；
上面的写错了
如果是数据库里保存的   就取出来后MD5再赋值给str