public async Task <int> Delete(int student_id)
{
try
{
using (StudentRecordsEntities db = new StudentRecordsEntities())
{
Student std = await db.Students.FindAsync(student_id);
if (std != null)
{
if (db.StudentFiles.Any(x => x.StudentID == std.ID))
{
db.StudentFiles.RemoveRange(db.StudentFiles.Where(x => x.StudentID == std.ID));
}
db.Students.Remove(std);
return(await db.SaveChangesAsync());
}
else
{
return(await Task.FromResult(0));
}
}
}
catch (Exception)
{
return(await Task.FromResult(0));
}
}
public async Task <int> Update(Student std)
{
try
{
using (StudentRecordsEntities db = new StudentRecordsEntities())
{
Student new_std = await db.Students.FindAsync(std.ID);
new_std.Name = std.Name;
new_std.Grade = std.Grade;
new_std.DateOfBirth = std.DateOfBirth;
new_std.Address = std.Address;
db.Entry(new_std).State = EntityState.Modified;
if (std.StudentFiles != null && std.StudentFiles.Count > 0)
{
foreach (var item in std.StudentFiles)
{
db.StudentFiles.Add(new StudentFile {
FileSize = item.FileSize, FileName = item.FileName, StudentID = std.ID
});
}
}
return(await db.SaveChangesAsync());
}
}
catch (Exception)
{
return(await Task.FromResult(0));
}
}
public async Task <int> Add(Student std)
{
try
{
using (StudentRecordsEntities db = new StudentRecordsEntities())
{
db.Students.Add(std);
return(await db.SaveChangesAsync());
}
}
catch (Exception)
{
return(await Task.FromResult(0));
}
}
public async Task <string> DeleteFile(int file_id)
{
try
{
using (StudentRecordsEntities db = new StudentRecordsEntities())
{
StudentFile file = await db.StudentFiles.FindAsync(file_id);
string x = file.FileName;
db.StudentFiles.Remove(file);
await db.SaveChangesAsync();
return(await Task.FromResult(x));
}
}
catch (Exception)
{
return(await Task.FromResult(""));
}
}