Having used properties in an ObservableCollection, you are probably familiar with implementing INotifyPropertyChanged in your custom objects.
A property utilizing this implementation would look like this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 | private string phoneNumberValue = String.Empty;public string PhoneNumber{ get { return this.phoneNumberValue; } set { if (value != this.phoneNumberValue) { this.phoneNumberValue = value; NotifyPropertyChanged("PhoneNumber"); } }} |
To remedy this repetitive implementation, I created this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 | /// <summary>/// Extends the INotifyPropertyChanged interface to the class properties./// </summary>public abstract class ViewModelBase : INotifyPropertyChanged{ #region Methods /// <summary> /// To be used within the "set" accessor in each property. /// This invokes the OnPropertyChanged method. /// </summary> /// <typeparam name="T"></param> /// <param name="name"></param> /// <param name="value"></param> /// <param name="newValue"></param> protected void SetValue&amp;amp;amp;lt;T&amp;amp;amp;gt;(string name, ref T value, ref T newValue) { if (newValue != null) { if (!newValue.Equals(value)) { value = newValue; OnPropertyChanged(name); } } else { value = default(T); } } #endregion #region INotifyPropertyChanged /// <summary> /// The PropertyChanged event handler. /// </summary> public event PropertyChangedEventHandler PropertyChanged; /// <summary> /// Calls the PropertyChanged event /// </summary> /// <param name="propertyName"></param> protected void OnPropertyChanged(string propertyName) { PropertyChangedEventHandler handler = PropertyChanged; if (handler != null) { handler(this, new PropertyChangedEventArgs(propertyName)); } } #endregion} |
Then, all we need to do is inherit ViewModelBase in our custom object.
Now, our property would look something like this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 | private string phoneNumberValue = String.Empty;public string PhoneNumber{ get { return this.phoneNumberValue; } set { SetValue("PhoneNumber", ref this.phoneNumberValue, ref value); }} |
So, what was the reason for doing this?
- It avoids directly implementing INotifyPropertyChanged. This allows the ability to start up objects with this implementation much faster.
- Less coding and potential messes involving the set operator.
Update as of August 2022
Good news is since all the C# goodness over the last 10 years, I have greatly improved this implementation. It can be used like this:
1 2 3 4 5 6 7 | private string _phoneNumberValue = String.Empty;public string PhoneNumber{ get => _phoneNumberValue; set => NotifyOfChange(value, ref _phoneNumberValue);} |
Simple, right?