在 Class 中实现 INotifyPropertyChanged

Question

I created the INotifyPropertyChanged in a class

public class BindableBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        protected void Set<T>(ref T storage, T value, [CallerMemberName]string propertyName = null)
        {
            if (Equals(storage, value))
            {
                return;
            }

            storage = value;
            RaisePropertyChanged(propertyName);
        }

        protected void RaisePropertyChanged([CallerMemberName]string propertyName = null)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }
    }

Now when I try to use it in usercontrol

public partial class myUserControl : UserControl, BindableBase

I encounter the following error

myUserControl can not have multiple base class

Answer 1

INotifyPropertyChanged is intended for view model classes, not for the views (or user controls) themselves. Therefore you don't normally need them in the views. You should use dependency properties instead, if you want to add fields to a user control.

See the example on UserControl :

/// <summary>
/// Identifies the Value dependency property.
/// </summary>
public static readonly DependencyProperty ValueProperty =
    DependencyProperty.Register(
        "Value", typeof(decimal), typeof(NumericUpDown),
        new FrameworkPropertyMetadata(MinValue, new PropertyChangedCallback(OnValueChanged),
                                      new CoerceValueCallback(CoerceValue)));

/// <summary>
/// Gets or sets the value assigned to the control.
/// </summary>
public decimal Value
{          
    get { return (decimal)GetValue(ValueProperty); }
    set { SetValue(ValueProperty, value); }
}