Question

我试图将几个参数传递给控制器＆amp;根据那些参数我加入一些表过滤器我想要的最终结果（model1）。现在我想从model1中选择一些随机记录并将其详细信息提供给viewmodel。条件是，所选项目的总价格不能超过参数预算......我尝试过几种方式，但我不能这样做..

在我的控制器中我有这个;

public ActionResult planview(Double budget, DateTime startTime, DateTime endTime)
   {




       var model = from Ts in db.TimeSpans 
                   let time1 = EntityFunctions.CreateTime(Ts.StartTime.Value.Hour,
                                              Ts.StartTime.Value.Minute,
                                              Ts.StartTime.Value.Second)

                   let time2 = EntityFunctions.CreateTime(Ts.EndTime.Value.Hour,
                                             Ts.StartTime.Value.Minute,
                                             Ts.StartTime.Value.Second)
                   where (time1 > startTime.TimeOfDay && endTime.TimeOfDay > time1) || (time1 < startTime.TimeOfDay && endTime.TimeOfDay < time2) || (time1 < startTime.TimeOfDay && endTime.TimeOfDay > time2)
        select Ts;

       var model1 = from Ts1 in model
                    join ob in db.Objects on Ts1.ObjectId equals ob.Id
                    select new PlanObjectsViewModel { 

                        Id=ob.Id,
                        StartTime=Ts1.StartTime,
                        EndTime=Ts1.EndTime,
                        LocationId=Ts1.LocationId,
                        Name=ob.Name,
                        Price=ob.Price,
                        Description=ob.Description,
                        Image=ob.Image,
                        Type=ob.Type
                    };

       int count = 0;
       foreach (var item in model1)
       {

           count++;
       }

       Random rand = new Random();
       int temp=0;

       while(budget>temp)
       {
           int randi = rand.Next(0, count);
           foreach(var item in model1)
           if(item.Id==randi)
               //select that record ;
               // select new PlanObjectsViewModel { 

                       // Id=ob.Id,
                       // StartTime=Ts1.StartTime,
                       // EndTime=Ts1.EndTime,
                       // LocationId=Ts1.LocationId,
                       // Name=ob.Name,
                       // Price=ob.Price,
                       // Description=ob.Description,
                       // Image=ob.Image,
                       // Type=ob.Type
                    };
               //temp+=temp;
       }

我的viewmodel是;

 public class PlanObjectsViewModel
{

    public int? Id { get; set; }

    public DateTime? StartTime { get; set; }

    public DateTime? EndTime { get; set; }

    public int? LocationId { get; set; }

    public String Name { get; set; }

    public Double? Price { get; set; }

    public String Description { get; set; }

    public String Image { get; set; }

    public int? Type { get; set; }
}

其他型号;

public partial class TimeSpan
{
    public int Id { get; set; }
    public Nullable<System.DateTime> StartTime { get; set; }
    public Nullable<System.DateTime> EndTime { get; set; }
    public Nullable<System.DateTime> StartDate { get; set; }
    public Nullable<System.DateTime> EndDate { get; set; }
    public Nullable<int> LocationId { get; set; }
    public Nullable<int> ObjectId { get; set; }

    public virtual LocationInfo LocationInfo { get; set; }
    public virtual Object Object { get; set; }
}

和

 public partial class Object
{
    public Object()
    {
        this.ObjectCategories = new HashSet<ObjectCategory>();
        this.TimeSpans = new HashSet<TimeSpan>();
        this.Branches = new HashSet<Branch>();
        this.Events = new HashSet<Event>();
    }

    public int Id { get; set; }
    public string Name { get; set; }
    public Nullable<double> Price { get; set; }
    public string Description { get; set; }
    public string Image { get; set; }
    public Nullable<int> Type { get; set; }

    public virtual BaseType BaseType { get; set; }
    public virtual ICollection<ObjectCategory> ObjectCategories { get; set; }
    public virtual ICollection<TimeSpan> TimeSpans { get; set; }
    public virtual ICollection<Branch> Branches { get; set; }
    public virtual ICollection<Event> Events { get; set; }
}

任何人都可以建议一种方法吗？谢谢!!

Answer 1

以下内容应该让您入门（未经测试，因为我现在面前没有IDE）。而不是迭代项目从列表中获取随机项目，并将其添加到您要返回的结果，这是这些项目的列表。

注意：请注意，如果模型中的项目总数少于预算，则最终会出现紧急循环。

//List of items to return
List<PlanObjectsViewModel> result = new List<PlanObjectsViewModel>();

Random rand = new Random();
int temp=0;

while(budget>temp)
{
    //Get random item within selection
    int randi = rand.Next(0, count);
    var nthItem = model1.Skip(randi).First();

    //Remove this test if you are happy adding duplicates
    if (!result.Find(nthItem)
    {
        result.Add(nthItem); 

        //Update temp with calculation from nthItem just added
    }
}

如何从视图模型中获取随机记录

1 个答案: