学生管理系统<分层开发>

一：分层架构

搭建DAL层(数据访问层)、UI层(表示层)、BLL层(业务逻辑层)以及Model层(实体层)

各层的引用关系：

DAL、UI、BLL层引用Model层

UI层引用BLL层

BLL层引用DAL层

二：实现登录功能

StudentDAL层

定义一个bool变量，将Student对象作为参数，使用SqlParameter对象进行填充，判定count值，若大于0.返回真

        //01.写一个用于登录的方法
        public bool IsLogin(Student stu)
        {

            bool flag = false;

            //string sql = "select count(1) from student where studentname='" + stu.StudentName + "' and loginpwd='" + stu.LoginPwd + "'";

            string sql = "select count(1) from student where studentname=@name and LoginPwd=@pwd";

            SqlParameter[] para ={

                         new SqlParameter("@name",stu.StudentName),
                         new SqlParameter("@pwd",stu.LoginPwd)

                               };
            //02.将sql语句交给SQL服务器执行
            int count = Convert.ToInt32(SQLHelper.ExecuteScalar(sql,para));
            if (count > )
            {
                flag = true;
            }
            return flag;

        }

StudentBLL层  数据传递

   StudentDAL dal = new StudentDAL();

     //登录
     public bool isLogin(Student stu)
     {
         bool result = dal.IsLogin(stu);
         return result;

     }

UI层

获取两个文本框的值，定义bool变量，拿到登录的方法，传入参数

        //登录
        private void btnLogin_Click(object sender, EventArgs e)
        {
            StudentBLL bll = new StudentBLL();
            Student stu=new Student();
            stu.StudentName = txtName.Text;
            stu.LoginPwd = txtPwd.Text;

           bool result= bll.isLogin(stu);
            if (result)
            {
                frmMain frm = new frmMain();
                this.Hide();
                frm.Show();

            }

三 实现新增学生用户

StudentDAL层

        //添加学生

        public bool AddStudent(Student  stu)
        {
            bool flag = false;
            string sql = "insert into Student Values(@LoginPwd,@StudentName,@Gender,@GradeId,@Phone,@Address,@Birthday,@Email)";
            SqlParameter []para=
            {
            new SqlParameter("@LoginPwd",stu.LoginPwd),
            new SqlParameter("@StudentName",stu.StudentName),
            new SqlParameter("@Gender",stu.Gender),
            new SqlParameter("@GradeId",stu.GradeId),
            new SqlParameter("@Phone",stu.Phone),
            new SqlParameter("@Address",stu.Address),
            new SqlParameter("@Birthday",stu.Birthday),
            new SqlParameter("@Email",stu.Email),

            };

            int count = SQLHelper.ExecuteNonQuery(sql,para);
            if(count>)
            {
                flag = true;

            }
            return flag;

        }

StudentBLL层

     //添加学生
     public bool AddStudent(Student stu)
     {
         bool result = dal.AddStudent(stu);
         return result;

     }

UI层

        //保存
        private void btnEdit_Click(object sender, EventArgs e)
        {
            //从界面获取各个值
            Student stu = new Student();
            stu.LoginPwd = txtPwd.Text;
            stu.StudentName = txtName.Text;
            stu.Gender = rbtnFemale.Checked?"":"";
            stu.Phone = txtPhone.Text;
            stu.Address = txtAddress.Text;
            stu.Email = txtEmail.Text;
            //出生日期
            stu.Birthday = dpBirthday.Value;
            //年级编号
            stu.GradeId = Convert.ToInt32(cboGrade.SelectedValue);

            bool result = studal.AddStudent(stu);

            if (result)
            {
                MessageBox.Show("添加成功！");
            }
            else
            {
                MessageBox.Show("添加失败！");
            }
        }

四 加载学生信息<查询>

DAL层

返回的是泛型集合、可使用MyTool工具类或者foreach遍历

        //泛型
        public List<Student> GetAllStudent()
        {
           // List<Student> list = new List<Student>();

            string sql = "select * from Student";

            DataTable dt= SQLHelper.ExecuteDataTable(sql);

            MyTool tool = new MyTool();

            List<Student> list = tool.DataTableToList<Student>(dt);

            //foreach (DataRow item in dt.Rows)
            //{
            //    Student stu = new Student();
            //    stu.StudentName = item["StudentName"].ToString();
            //    stu.StudentNo = Convert.ToInt32(item["StudentNo"]);
            //    stu.LoginPwd =item["LoginPwd"].ToString();

            //    list.Add(stu);
            //}

            return list;

        }

BLL层

     //泛型
     public List<Student> GetAllStudent()
     {
         List<Student> list = dal.GetAllStudent();
         return list;    

     }

UI层

       StudentBLL stuBll = new StudentBLL();
        GradeBLL GBll = new GradeBLL();

        //主窗体
        private void FrmSearchByGrade_Load(object sender, EventArgs e)
        {
            //删除英文列
            dgvList.AutoGenerateColumns = false;

           List<Student>list= stuBll.GetAllStudent();
           dgvList.DataSource = list;

           List<Grade> glist = GBll.GetAllGrade();
            //绑定年级下拉框值
          cboGrade.ValueMember = "GradeId";
          cboGrade.DisplayMember = "GradeName";
          cboGrade.DataSource = glist;
        }

        //查询
        private void btnSearch_Click(object sender, EventArgs e)
        {
            int gradeid =Convert.ToInt32(cboGrade.SelectedValue);

            //使用BLL层
            List<Student> list = stuBll.ByGradeId(gradeid);
            dgvList.DataSource = list;

        }

五 删除学生信息

DAL层

       //删除
        public bool Delete(int stuNo)
        {
            bool flag = false;
            string sql="delete from Student where StudentNo=@No";
            SqlParameter para = new SqlParameter("@No",stuNo);
            int count = SQLHelper.ExecuteNonQuery(sql,para);
        if(count>)
        {
            flag = true;
        }
        return flag;
        }

BLL层

     //删除
     public bool Delete(int stuNo)
     {
         return dal.Delete(stuNo);

     }

UI层

注：光标位置

记录选中行的索引值 定义变量index、光标回到index-1

        //删除
        private void tsmi_del_Click(object sender, EventArgs e)
        {
            int stuno = Convert.ToInt32(dgvList.SelectedRows[].Cells["Column2"].Value);

            //记录选中行的索引值
            int index = dgvList.CurrentRow.Index;

            //MessageBox.Show(index.ToString());

            bool flag = stuBll.Delete(stuno);

            if(flag)
            {
                MessageBox.Show("删除成功！");
                List<Student> list = stuBll.GetAllStudent();
                dgvList.DataSource = list;

                //光标回到index-1
                dgvList[, index].Selected = true;
                dgvList.CurrentCell=dgvList[,index];
            }
        }

六 修改学生信息

DAL层

        //修改
        public bool UpdateInfo(Student stu)
        {
            bool flag = false;
            string sql = "update Student set StudentName=@stuName,Gender=@gender,Birthday=@birthday where StudentNo=@No";
            SqlParameter[] para =
            {
            new SqlParameter("@stuName",stu.StudentName),
            new SqlParameter("@gender",stu.Gender),
            new SqlParameter("@birthday",stu.Birthday),
            new SqlParameter("@No",stu.StudentNo)
            };
            int count = SQLHelper.ExecuteNonQuery(sql,para);
            if(count>)
            {
                flag = true;
            }
            return flag;
        }

BLL层：

     //修改
     public bool UpdateInfo(Student stu)
     {
         return dal.UpdateInfo(stu);
     }

窗体的关联：

  private void tsmi_update_Click(object sender, EventArgs e)
        {
            FrmUpdate frm = new FrmUpdate();
            frm.dgvList = dgvList;
            frm.Show();
        }

UI层  Load事件中实现窗体的传值

        StudentBLL stubll = new StudentBLL();
        public DataGridView dgvList;
        Student stu = new Student();

        private void FrmUpdate_Load(object sender, EventArgs e)
        {

            stu.StudentNo = Convert.ToInt32(dgvList.SelectedRows[].Cells["Column2"].Value);
            stu.StudentName = dgvList.SelectedRows[].Cells["name"].Value.ToString();
            stu.Gender = dgvList.SelectedRows[].Cells["Column3"].Value.ToString();
            stu.Birthday = Convert.ToDateTime(dgvList.SelectedRows[].Cells["Column4"].Value);

           // MessageBox.Show(stu.StudentName.ToString());
            this.txtNo.Text = stu.StudentNo.ToString();
            this.txtName.Text = stu.StudentName;
            this.txtGender.Text = stu.Gender;
            this.txtBirthday.Text = stu.Birthday.ToString();
        }

        private void btnUpdate_Click(object sender, EventArgs e)
        {

            stu.StudentName = txtName.Text;
            stu.Gender = txtGender.Text;
            stu.Birthday = Convert.ToDateTime(txtBirthday.Text);
            bool flag = stubll.UpdateInfo(stu);
            if(flag)
            {
                MessageBox.Show("修改成功！！");
                List<Student> list = stubll.GetAllStudent();
                dgvList.DataSource = list;
            }
        }