Remove from ObservableCollection objects whose name appears in another list

Question

I have ObservableCollection aandList b

Now I want to remove aitems from the collection that have their equivalent in the list b.

My code at the moment:

public static void CrossRemove<TFirst, TSecond>(this ObservableCollection<TFirst> collection, IEnumerable<TSecond> secondCollection, Func<TFirst, TSecond, bool> predicate)
{
    collection.Where(first => secondCollection.Any(second => predicate(first, second)))
        .ToList().ForEach(item => collection.Remove(item));
}

using:

ObservableCollection<string> first = new ObservableCollection<string> { "1", "2", "3", "4", "5", "6", "k" };

IEnumerable<int> second = new List<int> { 2, 3, 5 };

first.CrossRemove(second, (x, y) => x == y.ToString());

this code removes “2”, “3” and “5” from the collection, leaving “1”, “4”, “6” and “k”.

In my real code aand bcontains elements that are inherited from one and the same interface, and I compare the property, which is in the interface, but I can not take it.

I cannot create a new list because it is bound to the wpf view, and if I do this, instead of visible crashes, crashes will be detected.

- / ?

Answer 1

HashSet<T> . ForEach ForEach. , .

void Main()
{
    ObservableCollection<MyClass> first = new ObservableCollection<MyClass> { "1", "2", "3", "4", "5", "6", "k" };

    ISet<IMyInterface> second = new HashSet<IMyInterface>(new MyClass2[] { 2, 3, 5 }, new MyEqualityComparer());

    first.CrossRemove(second);

    Console.WriteLine(string.Join(", ", first.Select(x => x.MyProperty)));
    // 1, 4, 6, k
}
public interface IMyInterface
{
    string MyProperty { get; set; }
}
public class MyEqualityComparer : IEqualityComparer<IMyInterface>
{
    public bool Equals(IMyInterface a, IMyInterface b)
    {
        return a.MyProperty == b.MyProperty;
    }
    public int GetHashCode(IMyInterface obj)
    {
        return obj.MyProperty.GetHashCode();
    }
}
public static class Extensions
{
    public static void CrossRemove<TFirst, TSecond>(this ObservableCollection<TFirst> collection, ISet<TSecond> set) where TFirst : TSecond
    {
        foreach (var item in collection.Where(item => set.Contains(item)).ToList())
            collection.Remove(item);
    }
}
public class MyClass : IMyInterface
{
    public string MyProperty { get; set; }
    public static implicit operator MyClass(string s)
    {
        return new MyClass { MyProperty = s };
    }
}
public class MyClass2 : IMyInterface
{
    public string MyProperty { get; set; }
    public static implicit operator MyClass2(int i)
    {
        return new MyClass2 { MyProperty = i.ToString() };
    }
}

, IEqualityComparer<object>, , . - :

(TypeA a, TypeB b) => a.PropA == b.PropB

:

public class MyOtherEqualityComparer : IEqualityComparer<object>
{
    private object GetProperty(object obj)
    {
        if (obj is TypeA)
            return ((TypeA)obj).PropA;
        else if (obj is TypeB)
            return ((TypeB)obj).PropB;
        else
            throw new Exception();
    }
    public bool Equals(object a, object b)
    {
        return GetProperty(a).Equals(GetProperty(b));
    }
    public int GetHashCode(object obj)
    {
        return GetProperty(obj).GetHashCode();
    }
}

Answer 2

, - List<T> RemoveAll, .

first.CrossRemove(second, (x, y) => x == y.ToString());

first.RemoveAll(item1 => second.Any(item2 => item1 == item2.ToString()));

, ObservableCollection<T> , :

public static class Extensions
{
    public static void RemoveAll<T>(this ICollection<T> collection, Func<T, bool> pred)
    {
        var toBeRemoved = collection.Where(pred).ToArray();
        foreach (var item in toBeRemoved)
            collection.Remove(item);
    }
}

EDIT:

, , , . , , , , ObservableCollection<T>, . , , . , , , , .