#pragma warning restore CA1000 // Do not declare static members on generic types
#endregion
#region Internal Static Methods
internal static object ProvideValue(
DependencyObject target,
DependencyProperty property,
object defaultValue,
BindingBase xamlBinding)
{
if (target == null ||
property == null)
{
return(null);
}
object outputValue = defaultValue;
if (outputValue == null ||
string.IsNullOrEmpty(outputValue.ToString()))
{
throw new InvalidOperationException($@"No default value provided for property ""{target}.{property.Name}""");
}
if (!outputValue.GetType().IsSerializable)
{
throw new InvalidOperationException($@"Default value provided for property ""{target}.{property.Name}"" is not serializable");
}
FrameworkElement visualAnchor = AbstractPropertyState <TState, TElement, TProperty> .GetVisualAnchor(target);
if (!(target is FrameworkElement element) || visualAnchor != null)
{
element = visualAnchor;
}
var defaultString = outputValue as string;
if (!string.IsNullOrEmpty(defaultString))
{
outputValue = AbstractPropertyState <TState, TElement, TProperty> .ConvertFromString(target.GetType(), property, defaultString);
}
var propertyMultiValueConverter = new PropertyMultiValueConverter()
{
Target = element,
Property = property,
};
void handler(object s, RoutedEventArgs e)
{
if (element != null)
{
element.Loaded -= handler;
}
if (xamlBinding != null &&
!IsPropertyPersisted(target, property))
{
// Normally the persisted state is the initial value used
// for an element property when the UI is rendered, but if
// no value is persisted (and a data bound property is present)
// then use the data bound value.
propertyMultiValueConverter.PropertyValuePreference = PropertyValuePreference.DataBound;
}
if (!HasPropertyValue(target, property))
{
object value = AddPropertyValue(target, property, outputValue);
if (value == null)
{
throw new InvalidOperationException($@"The element ""{target}"" has no unique identifier for property persistence");
}
}
var multiBinding = new MultiBinding()
{
Converter = propertyMultiValueConverter,
Mode = BindingMode.TwoWay,
UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged,
};
// Add a new binding between the element property and the
// persisted state.
multiBinding.Bindings.Add(CreateStateBinding(target, property));
if (xamlBinding != null)
{
// If the element property was previously data bound in XAML
// then add that binding to the multibinding collection.
multiBinding.Bindings.Add(xamlBinding);
}
BindingOperations.SetBinding(target, property, multiBinding);
if (element.IsLoaded)
{
propertyMultiValueConverter.PropertyValuePreference = PropertyValuePreference.DataBound;
}
}
// Windows are already loaded when the application starts
// so need to invoke their loaded handlers manually.
if (target is Window)
{
handler(null, null);
}
// Keep track of the loaded handlers in case they need to
// activated manually later.
AddPropertyLoadedHandler(target, property, handler);
if (element != null)
{
element.Loaded += handler;
}
if (HasPropertyValue(target, property))
{
return(GetPropertyValue(target, property));
}
return(outputValue);
}
internal static string GetUidWithNamespace(DependencyObject element)
{
return($@"{AbstractPropertyState<TState, TElement, TProperty>.GetNamespace(element)}{AbstractPropertyState<TState, TElement, TProperty>.GetUid(element)}");
}