/// <summary>
/// Sets a binding between a <see cref="DependencyObject"/> with its <see cref="DependencyProperty"/>
/// or <see cref="PropertyInfo"/> and the LocalizeExtension<>
/// </summary>
/// <param name="targetObject">The target dependency object</param>
/// <param name="targetProperty">The target dependency property</param>
/// <returns>TRUE if the binding was setup successfully, otherwise FALSE (Binding already exists).</returns>
/// <exception cref="ArgumentException">If the <paramref name="targetProperty"/> is
/// not a <see cref="DependencyProperty"/> or <see cref="PropertyInfo"/>.</exception>
public bool SetBinding(DependencyObject targetObject, object targetProperty)
{
if (!(targetProperty is DependencyProperty ||
targetProperty is PropertyInfo))
{
throw new ArgumentException("The targetProperty should be a DependencyProperty or PropertyInfo!", "targetProperty");
}
// indicates, if the target object was found
bool foundInWeakReferences = false;
// search for the target in the target object list
foreach (KeyValuePair <WeakReference, object> wr in m_TargetObjects)
{
// if the target is the target of the weakreference
if (wr.Key.Target == targetObject && wr.Value == targetProperty)
{
// set the flag to true and stop searching
foundInWeakReferences = true;
break;
}
}
// if the target it's not collected already, collect it
if (!foundInWeakReferences)
{
// if it's the first object, add an event handler too
if (m_TargetObjects.Count == 0)
{
// add this localize extension to the WeakEventManager on LocalizeDictionary
LocalizeDictionary.Instance.AddEventListener(this);
}
// add the target as an dependency object as weakreference to the dependency object list
m_TargetObjects.Add(new WeakReference(targetObject), targetProperty);
// adds this localize extension to the ObjectDependencyManager to ensure the lifetime along with the targetobject
ObjectDependencyManager.AddObjectDependency(new WeakReference(targetObject), this);
// set the initial value of the dependency property
SetTargetValue(targetObject,
targetProperty,
FormatOutput(LocalizeDictionary.Instance.GetLocalizedObject <object>(
Assembly, Dict, Key, GetForcedCultureOrDefault())));
// return true, the binding was successfully
return(true);
}
// return false, the binding already exists
return(false);
}
/// <summary>
/// Provides the Value for the first Binding
/// </summary>
/// <remarks>
/// This method register the <see cref="EventHandler"/> <c>OnCultureChanged</c> on <c>LocalizeDictionary</c>
/// to get an acknowledge of changing the culture, if the passed <see cref="TargetObjects"/> type of <see cref="DependencyObject"/>.
///
/// !PROOF: On every single <see cref="UserControl"/>, Window, and Page,
/// there is a new SparedDP reference, and so there is every time a new <c>LocalizeExtension</c>!
/// Because of this, we don't need to notify every single DependencyObjects to update their value (for GC).
/// </remarks>
/// <param name="serviceProvider">
/// The <see cref="System.Windows.Markup.IProvideValueTarget"/> provided from the <see cref="MarkupExtension"/>
/// </param>
/// <returns>The founded item from the .resx directory or null if not founded</returns>
/// <exception cref="System.InvalidOperationException">
/// thrown if <paramref name="serviceProvider"/> is not type of <see cref="System.Windows.Markup.IProvideValueTarget"/>
/// </exception>
public override object ProvideValue(IServiceProvider serviceProvider)
{
// try to cast the passed serviceProvider to a IProvideValueTarget
IProvideValueTarget service = serviceProvider.GetService(typeof(IProvideValueTarget)) as IProvideValueTarget;
// if the cast fails, an exception will be thrown. (should never happen)
if (service == null)
{
throw new InvalidOperationException("IProvideValueTarget service is unavailable");
}
// if the service.TargetObject is a Binding, throw an exception
if (service.TargetObject is System.Windows.Data.Binding)
{
throw new InvalidOperationException("Use as binding is not supported!");
}
// declare a target property
object targetProperty = null;
// check if the service.TargetProperty is a DependencyProperty or a PropertyInfo
if (service.TargetProperty is DependencyProperty ||
service.TargetProperty is PropertyInfo)
{
// set the target property to the service.TargetProperty
targetProperty = service.TargetProperty;
}
// check if the target property is null
if (targetProperty == null)
{
// return this.
return(this);
}
// if the service.TargetObject is System.Windows.SharedDp (= not a DependencyObject), we return "this".
// the SharedDp will call this instance later again.
if (!(service.TargetObject is DependencyObject))
{
// by returning "this", the provide value will be called later again.
return(this);
}
// indicates, if the target object was found
bool foundInWeakReferences = false;
// search for the target in the target object list
foreach (KeyValuePair <WeakReference, object> wr in m_TargetObjects)
{
// if the target is the target of the weakreference
if (wr.Key.Target == service.TargetObject && wr.Value == service.TargetProperty)
{
// set the flag to true and stop searching
foundInWeakReferences = true;
break;
}
}
// if the target is a dependency object and it's not collected already, collect it
if (service.TargetObject is DependencyObject && !foundInWeakReferences)
{
// if it's the first object, add an event handler too
if (m_TargetObjects.Count == 0)
{
// add this localize extension to the WeakEventManager on LocalizeDictionary
LocalizeDictionary.Instance.AddEventListener(this);
}
// add the target as an dependency object as weakreference to the dependency object list
m_TargetObjects.Add(new WeakReference(service.TargetObject), service.TargetProperty);
// adds this localize extension to the ObjectDependencyManager to ensure the lifetime along with the targetobject
ObjectDependencyManager.AddObjectDependency(new WeakReference(service.TargetObject), this);
}
// return the new value for the DependencyProperty
return(LocalizeDictionary.Instance.GetLocalizedObject <object>(Assembly, Dict, Key, GetForcedCultureOrDefault()));
}
