Question

我有两个有一对多关系的课程。我想根据父类的主键计算子类中的记录数。

父表类

  public class SystemFamily
{
    public SystemFamily()
    {
        DateCreated = DateTime.Now;
        deleteFlag = false;

    }

    public int SystemFamilyID { get; set;}
    public string FamilyName { get; set; }
    public DateTime DateCreated { get; set; } 
    public string CreatedBy { get; set; }
    public bool deleteFlag { get; set; }
    public int SystemsCount {get;set;}
    public virtual ICollection<Systems> Systems { get; set; }
    public string SFamilyName
    {
        get
        {
            return FamilyName;
        } 
    }

 }

子表类

  public class Systems
{

    public int SystemsID { get; set; }
    public string SystemName { get; set; }
    public DateTime CreatedOn { get; set;}
    public string CreatedBy { get; set; }
    public int SystemFamilyID { get; set; }

    public virtual SystemFamily SystemFamily { get; set; }
}

我不确定应该在哪里进行计数。在视图或控制器中？所以我会在建议之后发布所需的代码。

提前致谢！ VINI

编辑1

    public ActionResult Index()

    {
        //List<Systems> systems;
        //var query = db.SystemFamily.Select(c => c.SystemFamilyID).ToList();
        //foreach (var sid in query)
        //{
        //    systems = db.Systems.Select(c => c.SystemFamilyID == sid).ToList();
        //}
        //int count = systems.Count();//Here you will  get count

        //ViewBag.Counts = count; 
        var viewmodel = new Sys_SysFam();
        foreach (var item in db.SystemFamily)
        {
            int id = item.SystemFamilyID;

            //SystemsCount 
            int count = db.Systems.Where(x => x.SystemFamilyID == id).Count();
            item.SystemsCount = count;
        }
        ViewBag.Count = db.SystemFamily.Where(x=>x.deleteFlag==false).Count();
        int count1 =db.Systems.Count();
        ViewBag.SCount = count1;
        return View(db.SystemFamily.Where(x=>x.deleteFlag==false).ToList());
    }

这是我认为逻辑应该去的动作方法！我正在尝试使用foreach循环。但它不起作用它抛出异常：＆＃39; System.Data.Entity.Core.EntityCommandExecutionException＆＃39;

但我也有一个ViewSystem可以返回特定系列中的系统。

ViewSystem

    public ActionResult ViewSystem(int? id)
    {
            var viewmodel = new Sys_SysFam();
            ViewBag.SystemFamilyID = id;
            if (id != null)
            {
                ViewBag.SystemFamilyID = id.Value;
                var sysFamily = db.SystemFamily.Include(x => x.Systems).FirstOrDefault(x => x.SystemFamilyID == id.Value);
                if (sysFamily != null)
                {
                    viewmodel.Systems = sysFamily.Systems;
                }
            }

            return View(viewmodel);

    }

Answer 1

你必须在Controller

中这样做

public  ActionResult ActionMethordNam()
{
   List<Systems>  systems;
   var query = db.SystemFamily.Select(c=>c.SystemFamilyID).Tolist(); 
   foreach(var sid in query)
   { 
      systems = db.Systems.Select(c=>c.SystemFamilyID == sid).Tolist(); 
   }
   int count=systems.Count();//Here you will  get count

   Viewbag.Counts  = count; 
   return View();
}

查看依据

中的计数 .cshtml中的

@Viewbag.Counts

@Html.TextBox("syscount", (string)ViewBag.Counts)

您可以通过传递作为参数将post方法中的值检索到post方法，现在您可以通过将此值分配给模型属性来将数据保存到表中

Answer 2

 var dataList =  db.SystemFamily.Where(x => x.SystemFamilyID == id.Value).SelectMany(s => s.Systems).GroupBy(key => key.SystemFamilyID, sys => new {sys},
               (i, sys) =>
               new SystemsViewModel{
                 System = sys,
                 Count = sys.Count()
               }).ToList();

将dataList传递给View

以mvc计算子表中的记录数

2 个答案: