public BindingExpression(DependencyObject target, DependencyProperty targetProperty, PropertyPath path,
object source = null, RelativeSource relativeSource = null, string elementName = null,
BindingMode mode = BindingMode.Default, UpdateSourceTrigger updateSourceTrigger = UpdateSourceTrigger.Default,
IValueConverter converter = null, object converterParameter = null, object fallbackValue = null, object targetNullValue = null)
{
this.Target = target;
this.TargetProperty = targetProperty;
this.Path = path;
this.Source = source;
this.RelativeSource = relativeSource;
this.ElementName = elementName;
this.Mode = mode;
this.UpdateSourceTrigger = updateSourceTrigger;
this.Converter = converter;
this.ConverterParameter = converterParameter;
this.FallbackValue = fallbackValue;
this.TargetNullValue = targetNullValue;
Status = BindingStatus.Inactive;
disableSourceUpdate = new ReentrancyLock();
disableTargetUpdate = new ReentrancyLock();
targetValue = new ObservableValue(Target.GetValue(TargetProperty));
targetValue.ValueChanged += OnTargetValueChanged;
BindingMode resolvedBindingMode = Mode == BindingMode.Default ? GetDefaultBindingMode(Target, TargetProperty) : Mode;
isSourceUpdateMode = resolvedBindingMode == BindingMode.TwoWay || resolvedBindingMode == BindingMode.OneWayToSource;
isTargetUpdateMode = resolvedBindingMode == BindingMode.TwoWay || resolvedBindingMode == BindingMode.OneWay;
sourceObserver = CreateSourceObserver(Target, Source, RelativeSource, ElementName);
sourceExpression = new ObservableExpression(sourceObserver, Path ?? PropertyPath.Empty);
// try to update the target (or the source on OneWayToSource)
if (isTargetUpdateMode)
{
sourceExpression.ValueChanged += (sender, oldValue, newValue) => UpdateTargetOnSourceChanged();
UpdateTargetOnSourceChanged();
}
else if (isSourceUpdateMode)
{
sourceExpression.ValueChanged += (sender, oldValue, newValue) =>
{
if (Status == BindingStatus.UpdateSourceError && sourceExpression.Value != ObservableValue.UnsetValue && !disableTargetUpdate)
{
// source was connected
UpdateSourceOnTargetChanged();
}
};
UpdateSourceOnTargetChanged();
}
if (UpdateSourceTrigger == UpdateSourceTrigger.LostFocus && isSourceUpdateMode && Target is UIElement)
{
((UIElement)Target).LostFocus += OnLostFocus;
}
}
public BindingExpression(DependencyObject target, DependencyProperty targetProperty, PropertyPath path,
object source = null, RelativeSource relativeSource = null, string elementName = null,
BindingMode mode = BindingMode.Default, UpdateSourceTrigger updateSourceTrigger = UpdateSourceTrigger.Default,
IValueConverter converter = null, object converterParameter = null, object fallbackValue = null, object targetNullValue = null)
{
this.Target = target;
this.TargetProperty = targetProperty;
this.Path = path;
this.Source = source;
this.RelativeSource = relativeSource;
this.ElementName = elementName;
this.Mode = mode;
this.UpdateSourceTrigger = updateSourceTrigger;
this.Converter = converter;
this.ConverterParameter = converterParameter;
this.FallbackValue = fallbackValue;
this.TargetNullValue = targetNullValue;
Status = BindingStatus.Inactive;
disableSourceUpdate = new ReentrancyLock();
disableTargetUpdate = new ReentrancyLock();
targetValue = new ObservableValue(Target.GetValue(TargetProperty));
targetValue.ValueChanged += OnTargetValueChanged;
BindingMode resolvedBindingMode = Mode == BindingMode.Default ? GetDefaultBindingMode(Target, TargetProperty) : Mode;
isSourceUpdateMode = resolvedBindingMode == BindingMode.TwoWay || resolvedBindingMode == BindingMode.OneWayToSource;
isTargetUpdateMode = resolvedBindingMode == BindingMode.TwoWay || resolvedBindingMode == BindingMode.OneWay;
object resolvedSource = Source ?? GetRelativeSource(Target, RelativeSource, ElementName);
sourceExpression = new ObservableExpression(resolvedSource, Path);
// try to update the target (or the source on OneWayToSource)
if (isTargetUpdateMode)
{
sourceExpression.ValueChanged += (sender, e) => UpdateTargetOnSourceChanged();
UpdateTargetOnSourceChanged();
}
else if (isSourceUpdateMode)
{
sourceExpression.ValueChanged += (sender, e) =>
{
if (Status == BindingStatus.UpdateSourceError && sourceExpression.Value != ObservableValue.UnsetValue && !disableTargetUpdate)
{
// source was connected
UpdateSourceOnTargetChanged();
}
};
UpdateSourceOnTargetChanged();
}
if (((RelativeSource != null && RelativeSource.Mode != RelativeSourceMode.Self) || !ElementName.IsNullOrEmpty()) && Target is Visual)
{
((Visual)Target).VisualAncestorChanged += OnTargetVisualAncestorChanged;
}
if (UpdateSourceTrigger == UpdateSourceTrigger.LostFocus && isSourceUpdateMode && Target is UIElement)
{
((UIElement)Target).LostFocus += OnLostFocus;
}
}
