//根据用户名，查询用户是否存在
public static Teacher SelectTeacherByUserName(string userName)
{
using (ExamDBEntities db = new ExamDBEntities()) {
Teacher teacher = db.Teachers.SingleOrDefault(t => t.TeacherLoginName == userName);
return(teacher);
}
}
public static List <Student> SelectAllStudent()
{
using (ExamDBEntities db = new ExamDBEntities())
{
return(db.Students.ToList());
}
}
public static bool UpdateStudentInfo(Student s)
{
try
{
////查询出来一个student
//Student stu = StudentServer.SelectStudentByID(s.StuID);
//ExamDBEntities db = new ExamDBEntities();
//db.Entry(stu).State = EntityState.Modified;
////逐个更新
//stu.StuName = s.StuName;
//stu.StuLoginName = s.StuLoginName;
//stu.StuSex = s.StuSex;
//stu.StuGrade = s.StuGrade;
//stu.StuEmail = s.StuEmail;
//stu.StuLoginPwd = s.StuLoginPwd;
//stu.StuPhone = s.StuPhone;
//查询出来一个student
Student stu = StudentServer.SelectStudentByID(s.StuID);
ExamDBEntities db = new ExamDBEntities();
//这也可以实现对象的快速修改，推荐用这个方法
db.Entry(s).State = EntityState.Modified; //直接将传入的对象，设置修改装填
db.SaveChanges();
return(true);
}
catch
{
return(false);
}
}
public static Student SelectStudentByID(int id)
{
using (ExamDBEntities db = new ExamDBEntities())
{
Student stu = db.Students.SingleOrDefault(s => s.StuID == id);
return(stu);
}
}
public static Student SelectStudentByName(string name)
{
using (ExamDBEntities db = new ExamDBEntities())
{
Student s = db.Students.FirstOrDefault(stu => stu.StuLoginName == name);
return(s);
}
}
public static bool AddStudent(Student s)
{
using (ExamDBEntities db = new ExamDBEntities())
{
try
{
db.Entry(s).State = EntityState.Added;//也可以不加，因为Add时，会自动修改状态
db.Students.Add(s);
db.SaveChanges();
return(true);
}
catch
{
return(false);
}
}
}
public static bool DeleteStudentByID(int id)
{
try
{
//获取要删除的学生信息
Student s = StudentServer.SelectStudentByID(id);
ExamDBEntities db = new ExamDBEntities();
//将要删除的学生对象状态，修改为删除。
db.Entry(s).State = EntityState.Deleted;
db.Students.Remove(s);//Remove删除
db.SaveChanges();
return(true);
}
catch
{
return(false);
}
}
public BestSellingProductsDataSource(ExamDBEntities context)
{
this._context = context;
}
