需要比较其他表的值

Question

我的模型中有 3 个类

型号

public class Student  
{  
public int id { get; set; }  
[Required]  
[DisplayName("Student Name")]  
public string Name { get; set; }  
[Required]  
public int RollNO { get; set; }  
public DateTime EnrollmentDate { get; set; }  
public ICollection<Record> Records { get; set; }  
}  

public class Record  
{  
public int Id { get; set; }  
public int StudentId { get; set; }  
public int SubjectId { get; set; }  
[Required]  
public int Marks { get; set; }  
public string Result { get; set; }  
public virtual Student Students { get; set; }  
public virtual Subject Subjects { get; set; }  
}  

public class Subject  
{  
public int id { get; set; }  
[Required]  
public string Title { get; set; }  
[Required]  
[DisplayName("Minimum Marks")]  
public int MinMarks { get; set; }  
[Required]  
[DisplayName("Max Marks")]  
public int MaxMarks { get; set; }  
public ICollection<Record> Records { get; set; }  
} 

在主题表中，我将创建每个主题并设置通过所需的最小和最大分数...现在在记录表（创建页面）中，我想将所选主题的最小分数与 Record.Marks 进行比较，如果它更少Record.Result 中的最小标记失败，如果大于 Record.Result 中的最大标记则通过...我还想将 Result.Marks 属性与 Subject.MaxMarks 进行比较，如果它大于 Subject.MaxMarks 用户应该以任何可能的形式出现错误...

这是我的控制器

控制器

public ActionResult Create([Bind(Include = "Id,StudentId,SubjectId,Marks,Result")] Record record,Subject subject)
{

    var selectedSubject = db.Subjects.Where(sub => subject.id == record.SubjectId).FirstOrDefault();

    if (record.Marks < selectedSubject.MinMarks)
    {
        record.Result = "Fail";
    }
    else
        record.Result = "Pass";

    if (ModelState.IsValid)
    {
        db.Records.Add(record);
        db.SaveChanges();
        return RedirectToAction("Index");
    }

    ViewBag.StudentId = new SelectList(db.Students, "id", "Name", record.StudentId);
    ViewBag.SubjectId = new SelectList(db.Subjects, "id", "Title", record.SubjectId);
    return View(record);
}

Answer 1

假设您的视图有 input 元素来选择/输入主题 ID，并且元素的 name 属性值为 SubjectId 并且它在 form 内

只需添加一个 else if 来检查最大标记。您的操作方法中不需要第二个参数。只需将其删除。

var selectedSubject = db.Subjects.FirstOrDefault(a=> a.id == record.SubjectId);
if(selectedSubject!=null)
{     

  if (record.Marks < selectedSubject.MinMarks)
  {
    record.Result = "Fail";
  }
  else if (record.Marks > selectedSubject.MaxMarks)
  {
    record.Result = "Error";
  }
  else
  {
    record.Result = "Pass";
  }
}
else
{
  ModelState.AddModeError(string.empty,"Subject not found");
}
//to do : Reload dropdown data and return the view