How do I know if ObservableCollection has changed?

4 Answers

Implement INotifyPropertyChanged in your Product class with notification for every property.
Implement INotifyPropertyChanged in your viewmodel.
Add property IsDirty to your ViewModel (with notification through INotifyPropertyChanged .

What is the difference between ObservableCollection and BindingList?

The true difference is rather straightforward: ObservableCollection implements INotifyCollectionChanged which provides notification when the collection is changed (you guessed ^^) It allows the binding engine to update the UI when the ObservableCollection is updated. However, BindingList implements IBindingList .

Does ObservableCollection implement INotifyCollectionChanged?

In fact, this is the most adopted way. The ObservableCollection is inherited in this case, the ObservableCollection already implements the INotifyCollectionChanged, and thus, any update operations those affect the collection will be automatically reflected at the XAML side.

What is ObservableCollection in C#?

An ObservableCollection is a dynamic collection of objects of a given type. Objects can be added, removed or be updated with an automatic notification of actions. When an object is added to or removed from an observable collection, the UI is automatically updated.

How will an object be notified if the property bound to it has been changed?

The INotifyPropertyChanged interface is used to notify clients, typically binding clients, that a property value has changed. For example, consider a Person object with a property called FirstName .

How do you cast IEnumerable to ObservableCollection?

var myObservableCollection = new ObservableCollection(myIEnumerable); This will make a shallow copy of the current IEnumerable and turn it in to a ObservableCollection. To make things even more simple you can create an Extension method out of it.

What is a collection C#?

Collection classes are specialized classes for data storage and retrieval. These classes provide support for stacks, queues, lists, and hash tables. Most collection classes implement the same interfaces. These classes create collections of objects of the Object class, which is the base class for all data types in C#.

Why do we use INotifyPropertyChanged?

INotifyPropertyChanged interface is used to notify the view or ViewModel that it does not matter which property is binding; it is updated. Let’s take an example for understanding this interface. Take one WPF Window in which there are a total of three fields: First Name, Last Name and Full Name.

What are routed events in WPF?

A routed event is a CLR event that is backed by an instance of the RoutedEvent class and registered with the WPF event system. The RoutedEvent instance obtained from registration is typically retained as a public static readonly field member of the class that registers and thus “owns” the routed event.

How do you bind a list?

Following are some simple steps to bind your listbox/dropdown list to List.

Create a List in you code behind file i.e. . CS file. Following code shows how the List of string is created.
After creating List, bind List with your listbox/dropdown list. The following code binds to dropdown and listbox too.

What is BindingList?

BindingList is a generic list type that has additional binding support. While you can bind to a generic list, BindingList provides additional control over list items, i.e. if they can be edited, removed or added. BindingList also surfaces events that notify when the list has been changed.

When does an item in the observablecollection change?

ObservableCollection .CollectionChanged According to the documentation: “This event occurs when an item is added, removed, changed, moved or the entire list is refreshed.” However it does not occur if a property on an object in the collection changes, even if that object implements the INotifyPropertyChanged.

Where do I find the notifycollectionchanged event object?

The following example demonstrates the CollectionChanged event: The NotifyCollectionChangedEventArgs object resides in the System.Collections.Specialized namespace. If I run the RunObservableCollectionCode method I get the following output:

When to raise the inotifycollectionchanged event in WPF?

This interface exposes the CollectionChanged event, an event that should be raised whenever the underlying collection changes. WPF provides the ObservableCollection class, which is a built-in implementation of a data collection that implements the INotifyCollectionChanged interface.

Can you use observablecollection as an XAML object?

For more information, see “Binding to Collections” in Data Binding Overview. ObservableCollection can be used as a XAML object element in Windows Presentation Foundation (WPF), in versions 3.0 and 3.5. However, the usage has substantial limitations.

How do I know if ObservableCollection has changed? 4 Answers Implement INotifyPropertyChanged in your Product class with notification for every property. Implement INotifyPropertyChanged in your viewmodel. Add property IsDirty to your ViewModel (with notification through INotifyPropertyChanged . What is the difference between ObservableCollection and BindingList? The true difference is rather straightforward: ObservableCollection implements INotifyCollectionChanged which…