I have a WPF application that uses MVVM data bindings. I am adding items to an ObservableCollection<...>
and quite many of them indeed.
Now I am wondering that every time I add one to the collection, does it instantly fire the event and cause unnecessary overhead? If so, can I somehow temporarily disable the event notifications and manually fire it once at the end of my code so that if I add 10k items, it gets only fired once, rather than 10k times?
Update: I tried having this class:
using System;
using System.Linq;
using System.Collections.Specialized;
using System.Collections.Generic;
namespace MyProject
{
/// <summary>
/// Represents a dynamic data collection that provides notifications when items get added, removed, or when the whole list is refreshed.
/// </summary>
/// <typeparam name="T"></typeparam>
public class ObservableCollection<T> : System.Collections.ObjectModel.ObservableCollection<T>
{
/// <summary>
/// Adds the elements of the specified collection to the end of the ObservableCollection(Of T).
/// </summary>
public void AddRange(IEnumerable<T> collection)
{
foreach (var i in collection) Items.Add(i);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, collection.ToList()));
}
/// <summary>
/// Removes the first occurence of each item in the specified collection from ObservableCollection(Of T).
/// </summary>
public void RemoveRange(IEnumerable<T> collection)
{
foreach (var i in collection) Items.Remove(i);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, collection.ToList()));
}
/// <summary>
/// Clears the current collection and replaces it with the specified item.
/// </summary>
public void Replace(T item)
{
ReplaceRange(new T[] { item });
}
/// <summary>
/// Clears the current collection and replaces it with the specified collection.
/// </summary>
public void ReplaceRange(IEnumerable<T> collection)
{
List<T> old = new List<T>(Items);
Items.Clear();
foreach (var i in collection) Items.Add(i);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, collection.ToList()));
}
/// <summary>
/// Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class.
/// </summary>
public ObservableCollection() : base() { }
/// <summary>
/// Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class that contains elements copied from the specified collection.
/// </summary>
/// <param name="collection">collection: The collection from which the elements are copied.</param>
/// <exception cref="System.ArgumentNullException">The collection parameter cannot be null.</exception>
public ObservableCollection(IEnumerable<T> collection) : base(collection) { }
}
}
I get this error now:
Additional information: Range actions are not supported.
The error comes here:
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, collection.ToList()));
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