/// <summary>
/// Gets the current value of the property for the object
/// </summary>
/// <returns>
/// Returns an object or null
/// </returns>
/// <param name='instance'>
/// The object to look up in the values dictionary
/// </param>
/// <param name='property'>
/// The property describing the value to look up.
/// </param>
/// <param name='addIfMissing'>Adds a reference if not found</param>
private static KeyValueWeakReference GetCurrent(object instance, AttachedProperty property, bool addIfMissing)
{
KeyValueWeakReference result = null;
if (ValueDictionary.ContainsKey(instance))
{
var values = ValueDictionary[instance];
result = values.FirstOrDefault(x => x.Target == instance && x.Key == property.PropertyKey);
if (result == null && addIfMissing)
{
result = new KeyValueWeakReference(instance, property.PropertyKey);
values.Add(result);
}
return(result);
}
if (addIfMissing)
{
result = new KeyValueWeakReference(instance, property.PropertyKey);
ValueDictionary.Add(instance, new List <KeyValueWeakReference>()
{
result
});
}
return(result);
}
/// <summary>
/// Gets the value of an AttachedProperty for an object
/// </summary>
/// <param name='instance'>
/// The instance for which the value is being retrieved
/// </param>
/// <param name='property'>
/// The AttachedProperty that defines the value being retrieved
/// </param>
/// <returns>Returns an object, the default value or null</returns>
public static object GetValue(this object instance, AttachedProperty property)
{
var current = GetCurrent(instance, property, false);
if (current != null)
{
return current.Value;
}
return property.Metadata.DefaultValue;
}
/// <summary>
/// Gets the value of an AttachedProperty for an object
/// </summary>
/// <param name='instance'>
/// The instance for which the value is being retrieved
/// </param>
/// <param name='property'>
/// The AttachedProperty that defines the value being retrieved
/// </param>
/// <returns>Returns an object, the default value or null</returns>
public static object GetValue(this object instance, AttachedProperty property)
{
var current = GetCurrent(instance, property, false);
if (current != null)
{
return(current.Value);
}
return(property.Metadata.DefaultValue);
}
/// <summary>
/// Sets the value of an AttachedProperty for an object
/// </summary>
/// <param name='instance'>
/// The instance for which the value is being set
/// </param>
/// <param name='property'>
/// The AttachedProperty that defines the value being set
/// </param>
/// <param name='value'>
/// The value of the property
/// </param>
public static void SetValue(this object instance, AttachedProperty property, object value)
{
var current = GetCurrent(instance, property, true);
var oldValue = current.Value;
current.Value = value;
if (oldValue != value && property.Metadata.ChangeCallback != null)
{
var args = new AttachedPropertyChangedEventArgs(property, value, oldValue);
property.Metadata.ChangeCallback(instance, args);
}
}
/// <summary>
/// Sets the value of an AttachedProperty for an object
/// </summary>
/// <param name='instance'>
/// The instance for which the value is being set
/// </param>
/// <param name='property'>
/// The AttachedProperty that defines the value being set
/// </param>
/// <param name='value'>
/// The value of the property
/// </param>
public static void SetValue(this object instance, AttachedProperty property, object value)
{
var current = GetCurrent(instance, property, true);
var oldValue = current.Value;
current.Value = value;
if (oldValue != value && property.Metadata.ChangeCallback != null)
{
var args = new AttachedPropertyChangedEventArgs(property, value, oldValue);
property.Metadata.ChangeCallback(instance, args);
}
}
/// <summary>
/// Initializes a new instance of the <see cref="MonoKit.DataBinding.AttachedPropertyChangedEventArgs"/> class.
/// </summary>
/// <param name='property'>
/// The AttachedProperty that changed value
/// </param>
/// <param name='newValue'>
/// The new value of the property
/// </param>
/// <param name='oldValue'>
/// The old value of the property
/// </param>
public AttachedPropertyChangedEventArgs(AttachedProperty property, object newValue, object oldValue)
{
this.Property = property;
this.NewValue = newValue;
this.OldValue = oldValue;
}
/// <summary>
/// Initializes a new instance of the <see cref="MonoKit.DataBinding.AttachedPropertyChangedEventArgs"/> class.
/// </summary>
/// <param name='property'>
/// The AttachedProperty that changed value
/// </param>
/// <param name='newValue'>
/// The new value of the property
/// </param>
/// <param name='oldValue'>
/// The old value of the property
/// </param>
public AttachedPropertyChangedEventArgs(AttachedProperty property, object newValue, object oldValue)
{
this.Property = property;
this.NewValue = newValue;
this.OldValue = oldValue;
}
/// <summary>
/// Gets the current value of the property for the object
/// </summary>
/// <returns>
/// Returns an object or null
/// </returns>
/// <param name='instance'>
/// The object to look up in the values dictionary
/// </param>
/// <param name='property'>
/// The property describing the value to look up.
/// </param>
/// <param name='addIfMissing'>Adds a reference if not found</param>
private static KeyValueWeakReference GetCurrent(object instance, AttachedProperty property, bool addIfMissing)
{
KeyValueWeakReference result = null;
if (ValueDictionary.ContainsKey(instance))
{
var values = ValueDictionary[instance];
result = values.FirstOrDefault(x => x.Target == instance && x.Key == property.PropertyKey);
if (result == null && addIfMissing)
{
result = new KeyValueWeakReference(instance, property.PropertyKey);
values.Add(result);
}
return result;
}
if (addIfMissing)
{
result = new KeyValueWeakReference(instance, property.PropertyKey);
ValueDictionary.Add(instance, new List<KeyValueWeakReference>() { result });
}
return result;
}
