public async Task DeleteByIdAsync(long id)
{
using (MyDbContent cxt = new MyDbContent())
{
Student st = await cxt.Students.FirstAsync(s => s.Id == id);
cxt.Entry(st).State = EntityState.Deleted;
await cxt.SaveChangesAsync();
}
}
public async Task <long> AddAsync(string name, int age)
{
using (MyDbContent cxt = new MyDbContent())
{
Student st = new Student()
{
Name = name, Age = age, StuNo = "11111111"
};
cxt.Students.Add(st);
//cxt.SaveChanges();
await cxt.SaveChangesAsync();//使用异步版本
return(st.Id);
}
}
public async Task <IEnumerable <StudentDTO> > GetAllAsync()
{
using (MyDbContent cxt = new MyDbContent())
{
List <StudentDTO> students = new List <StudentDTO>();
//foreach (var student in cxt.Students)
//{
// StudentDTO dto = new StudentDTO() { Id = student.Id, Name = student.Name, Age = student.Age };
// students.Add(dto);
//}
await cxt.Students.ForEachAsync <Student>(student => { StudentDTO dto = new StudentDTO()
{
Id = student.Id, Name = student.Name, Age = student.Age
}; students.Add(dto); });
return(students);
}
}
public async Task <StudentDTO> GetByIdAsync(long id)
{
using (MyDbContent cxt = new MyDbContent())
{
Student st = await cxt.Students.FirstAsync(s => s.Id == id);
if (st != null)
{
StudentDTO dto = new StudentDTO()
{
Id = st.Id, Name = st.Name, Age = st.Age
};
return(dto);
}
else
{
return(null);
}
}
}
