写一个简单的登录客户端步骤

1,首先就是先写好配置文件,SqlHelper,CommnoHelper等工具类。

2,做一个注册界面,其实就是插入语句,比方说:insert into T_seats values(@login,@realname,@password)

注意:传进去的值要提前用MD5处理一下

3,做一个登录界面,因为要为修改密码准备,所以就在Sql语句中先只验证登录的用户名正不正确,然后根据查询出的密码与输入的密码比对,验证密码是否正确。登录成功后让修改密码按钮可用

部分代码 :

 string sql = "select * from T_seats where loginname=@login";
            SqlParameter[] pms = new SqlParameter[] {
                new SqlParameter("@login",login)
            };
           using(SqlDataReader read= SqlHelper.EXcuteReader(sql,CommandType.Text,pms))
           {
               if (read.HasRows)
               {
                   if(read.Read())
                   {
                       string password1 = read.GetString(3);
                       if (password1 == password)
                       {
                           ziduanHelp.id = read.GetInt32(0);
                           ziduanHelp.realname = read.GetString(2);
                           button2.Enabled = true;
                           MessageBox.Show("登录成功!");
                       }
                       else
                       {
                           MessageBox.Show("密码错误!");
                       }
                   }
               }
               else
               {
                   MessageBox.Show("用户名不存在!");
                }
           }

4,修改密码:上来先验证两次输入的密码一不一致,如如不一致,就直接提示错误,省的连数据库了。

  在登录的时候要不主键id拿到,可以建一个静态类,这样所有窗体就都以共用了。

  然后再根据Sql语句判断输入的旧密码与id是否与登录的这个用户名一致,以此判断旧密码是否输入正确。

  如果旧密码正确,接下来就可以更新了,为了代码清晰,把更新语句单独写到一个方法里面

修改密码代码如下:

 private void btn_Click(object sender, EventArgs e)
        {
            if (txtPwd1.Text == txtPwd2.Text)
            {
                String sql = "select count(*) from T_seats where id=@id and password=@password";
                SqlParameter[] pms = new SqlParameter[] {
                    new SqlParameter("@id",ziduanHelp.id),
                    new SqlParameter("@password",CommonHelp.MD5Encrypt(txtPassword.Text))
                };
              int r=(int)  SqlHelper.ExcuteScalar(sql,CommandType.Text,pms);
              if (r > 0)
              {
                  int w = ChacngePassword(ziduanHelp.id,CommonHelp.MD5Encrypt(txtPwd1.Text));
                  if (w > 0)
                  {
                      MessageBox.Show("修改成功!");
                  }
                  else
                  {
                      MessageBox.Show("修改失败!");
                  }
              }
              else
              {
                  MessageBox.Show("输入的旧密码错误!");
              }
            }
            else
            {
                MessageBox.Show("两次输入的密码不一致!");
            }
        }

        private int ChacngePassword(int p,string p1)
        {
            String sql = "update T_seats set password=@password where id=@id";
            SqlParameter[] pms = new SqlParameter[] {
                new SqlParameter("@password",p1),
                new SqlParameter("@id",p)
            };
          return  SqlHelper.ExcuteNonQuery(sql,CommandType.Text,pms);
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            this.Text = this.Text + "-" + ziduanHelp.realname;
        }


         

原文地址:https://www.cnblogs.com/tuibian/p/3355690.html