Question

我在检查列表相等性时遇到问题。我有以下列表：

List<RequestDetailViewModel> requestDetail

RequestDetailViewModel是：

public int PropertiesValueID { get; set; }
public int UnitID { get; set; }
public string Value { get; set; }
public int PropertyID { get; set; }

我有另一个列表“reqList”：

var reqList = (from p in db.RequestDetail
                        group new 
                        { p.PropertyID, p.UnitID , p.Value , p.PropertiesValueID }
                         by p.RequestID into reqG
                        select reqG
                       );

我想检查列表相等性像这样：

foreach (var item in reqList)
{

        if (requestDetail equals item)

        {
            return true;
        }
}

我该如何解决这个问题？

Answer 1

Modify your reqList select:

var reqList = (from p in db.RequestDetail
                      group new 
             { p.PropertyID, p.UnitID , p.Value , p.PropertiesValueID }
               by p.RequestID into reqG
                select new RequestDetailViewModel{
                  PropertyID = reqG.PropertyID, UnitID = reqG.UnitID ,
                  Value = reqG.Value , 
                  PropertiesValueID = reqG.PropertiesValueID 
                });

Will return List<RequestDetailViewModel>

Implement IComparable for your RequestDetailViewModel class then use SequenceEqual to compare two lists

Answer 2

Why don't you loop your View Model list, linq-querying the domain list for each item. Something like:

foreach (var detail in requestDetail)
{
    var reqListEqualItems = (from p in db.RequestDetail
                             where p.PropertyID == details.PropertyID &&
                                   p.UnitID == details.UnitID &&
                                   p.Value == details.Value &&
                                   p.PropertyID == details.PropertyID);
}

Something like that should give you the Domain Object items for each ViewModel item.

Answer 3

I would update the RequestDetailViewModel as follows:

public class RequestDetailViewModel : INotifyPropertyChanged
{
  private ResultDetail resultDetail;

  public RequestDetailViewModel(ResultDetail resultDetail)
  {
    this.resultDetail = resultDetail;
  }

  public ResultDetail
  {
     get
     {
       return this.resultDetail;
     }
  }

  public int PropertiesValueID 
  {
    get
    {
     return this.resultDetail.PropertiesValueID;
    }
    set
    {
       this.resultDetail.PropertiesValueID = value;
       this.RaisePropertyChanged("PropertiesValueID");
    }
  }

  public int UnitID 
  {
    get
    {
       return this.resultDetail.UnitID ;
    }
    set
    {
       this.resultDetail.UnitID = value;
       this.RaisePropertyChanged("UnitID");
    }
  }

  public string Value
  {
    get
    {
       return this.resultDetail.Value;
    }
    set
    {
       this.resultDetail.Value= value;
       this.RaisePropertyChanged("Value");
    }
  }

  public int PropertyID 
  {
    get
    {
       return this.resultDetail.PropertyID ;
    }
    set
    {
       this.resultDetail.PropertyID = value;
       this.RaisePropertyChanged("PropertyID");
    }
  }    
}

I'd also implement IEquatable in your DB model. and I'd do the check like this:

foreach (var item in reqList)
{
    if (requestDetail.ResultDetail.Equals(item))
    {
       return true;
    }
}

or better yet

return reqList.Any(item=> item.Equals(requestDetail.ResultDetail));

检查两个列表是否相同，不同类型

3 个答案: