private static void AssertValueSource(ValueSource valueSource, bool isCurrent = false, bool isExpression = false, BaseValueSource baseValueSource = BaseValueSource.Local)
{
Assert.AreEqual(isCurrent, valueSource.IsCurrent);
Assert.AreEqual(isExpression, valueSource.IsExpression);
Assert.AreEqual(baseValueSource, valueSource.BaseValueSource);
}
private void Update()
{
if (ignoreUpdate)
return;
this.isLocallySet = false;
this.isInvalidBinding = false;
this.isDatabound = false;
DependencyProperty dp = this.DependencyProperty;
DependencyObject d = target as DependencyObject;
if (SnoopModes.MultipleDispatcherMode && d != null && d.Dispatcher != this.Dispatcher)
return;
if (dp != null && d != null)
{
if (d.ReadLocalValue(dp) != DependencyProperty.UnsetValue)
this.isLocallySet = true;
BindingExpressionBase expression = BindingOperations.GetBindingExpressionBase(d, dp);
if (expression != null)
{
this.isDatabound = true;
if (expression.HasError || expression.Status != BindingStatus.Active)
{
this.isInvalidBinding = true;
StringBuilder builder = new StringBuilder();
StringWriter writer = new StringWriter(builder);
TextWriterTraceListener tracer = new TextWriterTraceListener(writer);
PresentationTraceSources.DataBindingSource.Listeners.Add(tracer);
// reset binding to get the error message.
ignoreUpdate = true;
d.ClearValue(dp);
BindingOperations.SetBinding(d, dp, expression.ParentBindingBase);
ignoreUpdate = false;
// this needs to happen on idle so that we can actually run the binding, which may occur asynchronously.
Dispatcher.BeginInvoke
(
DispatcherPriority.ApplicationIdle,
new DispatcherOperationCallback
(
delegate(object source)
{
bindingError = builder.ToString();
this.OnPropertyChanged("BindingError");
PresentationTraceSources.DataBindingSource.Listeners.Remove(tracer);
writer.Close();
return null;
}
),
null
);
}
else
{
bindingError = string.Empty;
}
}
this.valueSource = DependencyPropertyHelper.GetValueSource(d, dp);
}
this.OnPropertyChanged("IsLocallySet");
this.OnPropertyChanged("IsInvalidBinding");
this.OnPropertyChanged("StringValue");
this.OnPropertyChanged("DescriptiveValue");
this.OnPropertyChanged("IsDatabound");
this.OnPropertyChanged("IsExpression");
this.OnPropertyChanged("IsAnimated");
this.OnPropertyChanged("ValueSource");
}
internal static bool IsValueSourceHazardingCellRecycling( ValueSource valueSource )
{
switch( valueSource.BaseValueSource )
{
case BaseValueSource.Local:
case BaseValueSource.ParentTemplate:
case BaseValueSource.ParentTemplateTrigger:
case BaseValueSource.Unknown:
return true;
default:
return false;
}
}
