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



DAL层：（为了防止sql注入需要使用SqlParameter）

//登录
public bool LoginStudent(Student stu)
{
bool flag = false;
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)
};
int count=Convert.ToInt32(SQLHelper.ExecuteScalar(sql,para));
if (count > 0)
{
flag = true;
}
return flag;
}

BLL层：（只做数据传递的载体）

StudentDAL dal = new StudentDAL();
//登录
public bool IsLogin(Student stu)
{
bool result = dal.LoginStudent(stu);
return result;
}

UI层：

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)
{
MessageBox.Show("登录成功！");
FrmMain frm = new FrmMain();
this.Hide();
frm.Show();
}
else
{
MessageBox.Show("失败啦！");
}
}

效果：





登录成功后进入主界面



三 实现新增学生用户

效果：



DAL层：

//添加学生
public bool AddStudent(Student stu)
{
bool flag = false;
string sql = "insert into Student values('"+stu.StudentNo+"','"+stu.LoginPwd+"','"+stu.StudentName+"','"+stu.Sex+"','"+stu.GradeId+"','"+stu.Phone+"','"+stu.Address+"','"+stu.BornDate+"','"+stu.Email+"')";
int count = SQLHelper.ExecuteNonQuery(sql);
if (count > 0)
{
flag = true;
}
return flag;
}

BLL层：

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

UI层：

private void btnEdit_Click(object sender, EventArgs e)
{
stu.StudentNo = txtStudentNo.Text;
stu.LoginPwd = txtPwd.Text;
stu.StudentName = txtName.Text;
stu.Sex = rbtnFemale.Checked ? "0" : "1";
stu.GradeId = Convert.ToInt32(cboGrade.SelectedValue);
stu.Phone = txtPhone.Text;
stu.Address = txtAddress.Text;
stu.BornDate = dpBirthday.Value;
stu.Email = txtEmail.Text;

if (txtPwd.Text.Trim() != txtRePwd.Text.Trim())
{
MessageBox.Show("密码请输入一致!");
return;
}

bool re = bll.Add(stu);
if (re)
{
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>0)
{
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[0].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[0, index].Selected = true;
dgvList.CurrentCell=dgvList[0,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,Sex=@gender,BornDate=@birthday where StudentNo=@No";
SqlParameter[] para =
{
new SqlParameter("@stuName",stu.StudentName),
new SqlParameter("@Sex",stu.Gender),
new SqlParameter("@BornDate",stu.Birthday),
new SqlParameter("@No",stu.StudentNo)
};
int count = SQLHelper.ExecuteNonQuery(sql,para);
if(count>0)
{
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[0].Cells["Column2"].Value);
stu.StudentName = dgvList.SelectedRows[0].Cells["name"].Value.ToString();
stu.Sex= dgvList.SelectedRows[0].Cells["Column3"].Value.ToString();
stu.BornDate= Convert.ToDateTime(dgvList.SelectedRows[0].Cells["Column4"].Value);

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