How to insert an item at the beginning of an ObservableCollection?

Question

How can I do that? I need a list (of type ObservableCollection) where the latest item is first.

Answer 1

Try using

collection.Insert(0, item); 

This would add item to the beginning of the collection (while Add adds to the end). More info here.

Answer 2

You should use a stack instead.

This is based on Observable Stack and Queue

Create an observable Stack, where stack is always last in first out (LIFO).

from Sascha Holl

public class ObservableStack<T> : Stack<T>, INotifyCollectionChanged, INotifyPropertyChanged {     public ObservableStack()     {     }      public ObservableStack(IEnumerable<T> collection)     {         foreach (var item in collection)             base.Push(item);     }      public ObservableStack(List<T> list)     {         foreach (var item in list)             base.Push(item);     }       public new virtual void Clear()     {         base.Clear();         this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));     }      public new virtual T Pop()     {         var item = base.Pop();         this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, item));         return item;     }      public new virtual void Push(T item)     {         base.Push(item);         this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item));     }       public virtual event NotifyCollectionChangedEventHandler CollectionChanged;       protected virtual void OnCollectionChanged(NotifyCollectionChangedEventArgs e)     {         this.RaiseCollectionChanged(e);     }      protected virtual void OnPropertyChanged(PropertyChangedEventArgs e)     {         this.RaisePropertyChanged(e);     }       protected virtual event PropertyChangedEventHandler PropertyChanged;       private void RaiseCollectionChanged(NotifyCollectionChangedEventArgs e)     {         if (this.CollectionChanged != null)             this.CollectionChanged(this, e);     }      private void RaisePropertyChanged(PropertyChangedEventArgs e)     {         if (this.PropertyChanged != null)             this.PropertyChanged(this, e);     }       event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged     {         add { this.PropertyChanged += value; }         remove { this.PropertyChanged -= value; }     } } 

This calls INotifyCollectionChanged, does the same as a ObservableCollection, but in a stack manner.