public async Task <IActionResult> Create(CreateCourseWorkModel model)
        {
            if (ModelState.IsValid)
            {
                var courseWork = new CourseWork()
                {
                    Name        = model.Name,
                    Description = model.Description
                };

                using (var memoryStream = new MemoryStream())
                {
                    if (model.File != null)
                    {
                        courseWork.File_name = model.File.FileName;
                        await model.File.CopyToAsync(memoryStream);

                        courseWork.File = Convert.ToBase64String(memoryStream.ToArray());
                    }
                    else
                    {
                        return(RedirectToAction("Create"));
                    }
                }

                db.CourseWorks.Add(courseWork);
                await db.SaveChangesAsync();

                return(RedirectToAction("AllCourseWorks"));
            }

            return(null);
        }
        public async Task <IActionResult> Edit(CreateCourseWorkModel model)
        {
            if (ModelState.IsValid)
            {
                CourseWork old_courseWork = await db.CourseWorks.FirstOrDefaultAsync(p => p.Id == model.Id);

                old_courseWork.Name        = model.Name;
                old_courseWork.Description = model.Description;

                using (var memoryStream = new MemoryStream())
                {
                    if (model.File != null)
                    {
                        old_courseWork.File_name = model.File.FileName;
                        await model.File.CopyToAsync(memoryStream);

                        old_courseWork.File = Convert.ToBase64String(memoryStream.ToArray());
                    }
                }

                db.CourseWorks.Update(old_courseWork);
                await db.SaveChangesAsync();

                return(RedirectToAction("AllCourseWorks"));
            }

            return(null);
        }
        // редактирование существующей курсовой работы
        public async Task <IActionResult> Edit(int?id)
        {
            if (id != null)
            {
                CourseWork courseWork = await db.CourseWorks.FirstOrDefaultAsync(p => p.Id == id);

                if (courseWork != null)
                {
                    CreateCourseWorkModel courseWorkModel = new CreateCourseWorkModel()
                    {
                        Id          = courseWork.Id,
                        Name        = courseWork.Name,
                        Description = courseWork.Description
                    };

                    return(View(courseWorkModel));
                }
            }
            return(NotFound());
        }