/// <summary>
/// Internals the property change.
/// </summary>
/// <param name="modelInstance">The model instance.</param>
/// <param name="newValue">The new value.</param>
/// <param name="message">The message.</param>
private async void InternalPropertyChange(BindableBase modelInstance, TProperty newValue, string message)
{
//find out there will be a changing by makesure they are not equal
var changing = (this.EqualityComparer != null) ?
!this.EqualityComparer(newValue, _value) :
!Object.Equals(newValue, _value);
if (!changing)
{
return;
}
//fire changing event ask if anyone against changing
var changingArg = new ValueChangingEventArgs <TProperty>(message, _value, newValue);
modelInstance.RaisePropertyChanging(changingArg);
var oldvalue = _value;
_value = newValue;
await Task.Yield();
if (changingArg.Cancellation.IsCancellationRequested)
{
_value = oldvalue;
return;
}
if (ValueChanging != null)
{
ValueChanging.Invoke(this, changingArg);
await Task.Yield();
if (changingArg.Cancellation.IsCancellationRequested)
{
_value = oldvalue;
return;
}
}
if (NonGenericValueChanging != null)
{
NonGenericValueChanging.Invoke(this, changingArg);
await Task.Yield();
if (changingArg.Cancellation.IsCancellationRequested)
{
_value = oldvalue;
return;
}
}
ValueChangedEventArgs <TProperty> changedArg = new ValueChangedEventArgs <TProperty>(message, oldvalue, newValue);
modelInstance.RaisePropertyChanged(changedArg);
ValueChanged?.Invoke(this, changedArg);
NonGenericValueChanged?.Invoke(this, changedArg);
}
/// <summary>
/// Raises the <see cref="ValueChanging"/> event with the given parameters.
/// </summary>
/// <param name="args">The arguments of the event.</param>
protected void NotifyContentChanging(MemberNodeChangeEventArgs args)
{
PrepareChange?.Invoke(this, args);
ValueChanging?.Invoke(this, args);
}
private void OnValueChanging(object sender, MemberNodeChangeEventArgs e)
{
ValueChanging?.Invoke(sender, e);
}
/// <summary>
/// Raises the ValueChanging event
/// </summary>
/// <param name="oldValue">The old property value</param>
/// <param name="newValue">The expected new property value</param>
/// <param name="cancel">Set to True to cancel the property change</param>
protected virtual void RaisePropertyValueChanging(TValue oldValue, TValue newValue, ref bool cancel)
{
ValueChanging?.Invoke(Owner, oldValue, newValue, ref cancel);
}
/// <summary>
/// 値変更前イベントを発生させる。
/// </summary>
/// <param name="e">ValueChangingEventArgs</param>
protected virtual void InvokeValueChanging(ValueChangingEventArgs e)
{
ValueChanging?.Invoke(this, e);
}
protected void RaiseValueChanging(object newValue)
{
ValueChanging?.Invoke(this, new ValueChangingEventArgs(newValue));
}
protected virtual void OnValueChanging(object sender)
{
ValueChanging?.Invoke(sender);
}