public void TargetOrDefault_not_disposed_target_returns_target()
{
var target = new object();
var weakReference = new WeakReference <object>(target);
Assert.Equal(target, weakReference.TargetOrDefault());
}
public void TargetOrDefault_null_weakreference_throws_ArgumentNullException()
{
WeakReference <object>?weakReference = null;
#pragma warning disable CS8604 // Possible null reference argument.
Assert.Throws <ArgumentNullException>(() => weakReference.TargetOrDefault());
#pragma warning restore CS8604 // Possible null reference argument.
}
/// <summary>
/// <para>
/// Set <paramref name="storage"/> to a <see cref="WeakReference{T}"/> of the given <paramref name="value"/>.
/// </para>
/// <para>
/// If the given <paramref name="value"/> is different than the current value,
/// it raises an event on <see cref="INotifyPropertyChanging.PropertyChanging"/> before the storage changes and <see cref="INotifyPropertyChanged.PropertyChanged"/> after the storage was changed.
/// </para>
/// </summary>
/// <typeparam name="T">The type of the value to set.</typeparam>
/// <param name="storage">Reference to the storage field containing the <see cref="WeakReference{T}"/>.</param>
/// <param name="value">New value to set.</param>
/// <param name="oldValue">The old value of <paramref name="storage"/>.</param>
/// <param name="comparer">An optional comparer to compare the value of <paramref name="storage"/> and <paramref name="value"/>. If <see langword="null"/> is passed, the default comparer will be used.</param>
/// <param name="propertyName">Name of the property.</param>
/// <returns><see langword="true"/> if the value was different from the <paramref name="storage"/> variable and events on <see cref="PropertyChanging"/> and <see cref="PropertyChanged"/> were raised; otherwise, <see langword="false"/>.</returns>
protected bool SetProperty <T>(ref WeakReference <T> storage, T value, out T oldValue, IEqualityComparer <T> comparer = null, [CallerMemberName] string propertyName = null)
where T : class
{
oldValue = storage?.TargetOrDefault();
if ((comparer ?? EqualityComparer <T> .Default).Equals(oldValue, value))
{
return(false);
}
this.NotifyPropertyChanging(propertyName);
storage = value != null ? new WeakReference <T>(value) : default;
this.NotifyPropertyChanged(propertyName);
return(true);
}
/// <summary>
/// <para>
/// Set <paramref name="storage"/> to a <see cref="WeakReference{T}"/> of the given <paramref name="value"/>.
/// </para>
/// <para>
/// If the given <paramref name="value"/> is different than the current value,
/// it raises an event on <see cref="INotifyPropertyChanging.PropertyChanging"/> before the storage changes and <see cref="INotifyPropertyChanged.PropertyChanged"/> after the storage was changed.
/// </para>
/// </summary>
/// <typeparam name="T">The type of the value to set.</typeparam>
/// <param name="storage">Reference to the storage field containing the <see cref="WeakReference{T}"/>.</param>
/// <param name="value">New value to set.</param>
/// <param name="oldValue">The old value of <paramref name="storage"/>.</param>
/// <param name="comparer">An optional comparer to compare the value of <paramref name="storage"/> and <paramref name="value"/>. If <see langword="null"/> is passed, the default comparer will be used.</param>
/// <param name="propertyName">Name of the property.</param>
/// <returns><see langword="true"/> if the value was different from the <paramref name="storage"/> variable and events on <see cref="PropertyChanging"/> and <see cref="PropertyChanged"/> were raised; otherwise, <see langword="false"/>.</returns>
protected virtual bool SetProperty <T>(ref WeakReference <T>?storage, T?value, out T?oldValue, IEqualityComparer <T?>?comparer = null, [CallerMemberName] string?propertyName = null)
where T : class
{
oldValue = storage?.TargetOrDefault();
if ((comparer ?? EqualityComparer <T?> .Default).Equals(oldValue, value))
{
return(false);
}
NotifyPropertyChanging(propertyName);
storage = value is T tValue ? new WeakReference <T>(tValue) : default;
NotifyPropertyChanged(propertyName);
return(true);
}
public void TargetOrDefault_null_weakreference_throws_ArgumentNullException()
{
WeakReference <object> weakReference = null;
Assert.Throws <ArgumentNullException>(() => weakReference.TargetOrDefault());
}
