ObservableCollection<类名>. distinct()不起作用
本文关键字：不起作用 distinct 类名 ObservableCollection | 更新日期: 2023-09-27 18:08:30
我有下一个类:
public class MapsDescModel : NotificationObject, IEqualityComparer<MapsDescModel>
{
public MapsDescModel(ObservableCollection<MainCategories> mainCategoty)
{
MainCategories = mainCategoty;
}
private MainCategories _mainCategorySelectedItem;
public MainCategories MainCategorySelectedItem
{
get { return _mainCategorySelectedItem; }
set
{
if (Equals(value, _mainCategorySelectedItem)) return;
_mainCategorySelectedItem = value;
RaisePropertyChanged("MainCategorySelectedItem");
RaisePropertyChanged("SubCategories");
}
}
private SubCategories _subCategorySelectedItem;
public SubCategories SubCategorySelectedItem
{
get { return _subCategorySelectedItem; }
set
{
if (Equals(value, _subCategorySelectedItem)) return;
_subCategorySelectedItem = value;
RaisePropertyChanged("SubCategorySelectedItem");
}
}
private ObservableCollection<MainCategories> _mainCategories;
public ObservableCollection<MainCategories> MainCategories
{
get { return _mainCategories; }
set
{
if (Equals(value, _mainCategories)) return;
_mainCategories = value;
RaisePropertyChanged("MainCategories");
}
}
public ObservableCollection<SubCategories> SubCategories
{
get
{
if (MainCategorySelectedItem != null)
return
Infrastructure.Helpers.ExtensionMethods.ToObservableCollection(
MainCategorySelectedItem.SubCategory.AsEnumerable());
else return new ObservableCollection<SubCategories>();
}
}
public bool Equals(MapsDescModel x, MapsDescModel y)
{
return
x.MainCategorySelectedItem.MainCatID == y.MainCategorySelectedItem.MainCatID &&
x.SubCategorySelectedItem.SubCatID == y.SubCategorySelectedItem.SubCatID;
}
public int GetHashCode(MapsDescModel obj)
{
if (Object.ReferenceEquals(obj, null)) return 0;
if (obj.MainCategorySelectedItem == null || obj.SubCategorySelectedItem == null)
return 0;
else return obj.MainCategorySelectedItem.Category.GetHashCode() + obj.SubCategorySelectedItem.Category.GetHashCode();
}
}
和我有下一个集合在其他类:
MapsGrid = new ObservableCollection<MapsDescModel>()
我正在尝试使用MapGrid.Distinct()方法，但它不工作，因为它应该。
MainCatID和SubCatID的性质为Integer s。当我将2个具有相同属性值的对象插入到集合并使用Distinct方法时，什么也不会发生。我检查代码(Console.WriteLine(MapsGrid[0].Equals(MapsGrid[1]));)什么比较返回，它返回假，即使属性是相等的。我错在哪里?
更新:
我编辑了MapsDescModel类:
public class MapsDescModel : NotificationObject, IEqualityComparer<MapsDescModel>, IEquatable<MapsDescModel>
{
public MapsDescModel(ObservableCollection<MainCategories> mainCategoty)
{
MainCategories = mainCategoty;
}
private MainCategories _mainCategorySelectedItem;
public MainCategories MainCategorySelectedItem
{
get { return _mainCategorySelectedItem; }
set
{
if (Equals(value, _mainCategorySelectedItem)) return;
_mainCategorySelectedItem = value;
RaisePropertyChanged("MainCategorySelectedItem");
RaisePropertyChanged("SubCategories");
}
}
private SubCategories _subCategorySelectedItem;
public SubCategories SubCategorySelectedItem
{
get { return _subCategorySelectedItem; }
set
{
if (Equals(value, _subCategorySelectedItem)) return;
_subCategorySelectedItem = value;
RaisePropertyChanged("SubCategorySelectedItem");
}
}
private ObservableCollection<MainCategories> _mainCategories;
public ObservableCollection<MainCategories> MainCategories
{
get { return _mainCategories; }
set
{
if (Equals(value, _mainCategories)) return;
_mainCategories = value;
RaisePropertyChanged("MainCategories");
}
}
public ObservableCollection<SubCategories> SubCategories
{
get
{
if (MainCategorySelectedItem != null)
return
Infrastructure.Helpers.ExtensionMethods.ToObservableCollection(
MainCategorySelectedItem.SubCategory.AsEnumerable());
else return new ObservableCollection<SubCategories>();
}
}
public bool Equals(MapsDescModel x, MapsDescModel y)
{
if (x.MainCategorySelectedItem == null || x.SubCategorySelectedItem == null ||
y.MainCategorySelectedItem == null || y.SubCategorySelectedItem == null)
return false;
return
x.MainCategorySelectedItem.MainCatID == y.MainCategorySelectedItem.MainCatID &&
x.SubCategorySelectedItem.SubCatID == y.SubCategorySelectedItem.SubCatID;
}
public int GetHashCode(MapsDescModel obj)
{
if (Object.ReferenceEquals(obj, null)) return 0;
if (obj.MainCategorySelectedItem == null || obj.SubCategorySelectedItem == null)
return 0;
else return obj.MainCategorySelectedItem.Category.GetHashCode() + obj.SubCategorySelectedItem.Category.GetHashCode();
}
public bool Equals(MapsDescModel other)
{
return
this.Equals(this, other); // use definition from IEqualityComparer<T>
}
public override bool Equals(object obj)
{
MapsDescModel other = obj as MapsDescModel;
if (other == null)
return base.Equals(obj);
else
return this.Equals(other);
}
public override int GetHashCode()
{
MapsDescModel other = this as MapsDescModel;
if (other == null)
return base.GetHashCode();
else
return this.GetHashCode(other);
}
现在当我执行Distinct方法时，它仍然不起作用。我知道我的equals方法正在工作，因为行'Console.WriteLine(MapsGrid[0]. equals (MapsGrid[1]));'返回true。
任何想法?
您已经实现了IEqualityComparer<T>，如果您想将类的实例传递给Distinct，这是很好的:
var distinctList = MapGrid.Distinct(new MapsDescModel());
然而，一个更干净的方法是实现IEquatable<T>，因为Distinct将默认使用它，如果你不传递IEqualityComparer<T>:
public class MapsDescModel : NotificationObject, IEqualityComparer<MapsDescModel>, IEquatable<MapsDescModel>
{
...
public bool Equals(MapsDescModel y)
{
return
this.Equals(this,y); // use definition from IEqualityComparer<T>
}
}
我还建议重写object.Equals和object.GetHashCode以保持一致性，如果您喜欢，再次利用IEqualityComparer方法(或者如果您决定不再需要它们，则将IEqualityComparer方法转换为重写)。
如果你需要帮助，就回答问题。
是否重载bool =(对象obj)得到调用，它返回什么?
你的回答没有回答那个非常关键的问题。
因为你没有实现Object，我怀疑那些OverRides没有被调用
实现Equals方法
你正在应用IEqualityComparer类(MapsDescModel)，它适用于一个集合
IEqualityComparer接口
我认为你需要做的(或打算做的)是重写GetHashCode和等号上的类MainCategories
但是你没有发布MainCategories的定义
我发现这个符号很有趣，是
public ObservableCollection<MainCategories> MainCategories
集合的集合?
考虑不要用类的名字来命名属性