public static DependencyProperty Register(string name, Type propertyType, Type ownerType, PropertyMetadata metadata)
{
// Add a new list if this is the first time we've registered a property for this type
if (!registeredPropertiesByOwner.ContainsKey(ownerType))
registeredPropertiesByOwner.Add(ownerType, new List<DependencyProperty>());
var existingList = registeredPropertiesByOwner[ownerType];
// Now let's check to see if we've already registered a property with this type
var existingProperty = existingList.FirstOrDefault(dp => dp.Name == name);
if (existingProperty != null)
throw new ArgumentException(string.Format("Dependency Property already registered with name {0}", name));
var newProperty = new DependencyProperty(name, propertyType, ownerType, metadata);
existingList.Add(newProperty);
return newProperty;
}
protected object GetValue(DependencyProperty property)
{
if (property == null)
throw new ArgumentNullException("You must supply a DependencyProperty object.");
if (!dependencyPropertyValues.ContainsKey(property.Name))
return property.PropType.Default();
// If we set a binding on this property, then we need to query the binding for the value, not the pass back the binding
var obj = dependencyPropertyValues[property.Name];
if (obj is Binding)
return (obj as Binding).GetValue();
// Otherwise return what's here
return obj;
}
public void SetBinding(DependencyProperty property, Binding binding)
{
if (property == null)
throw new ArgumentNullException("You must supply a DependencyProperty object.");
// We don't want to go through SetValue because we're not passing in a concrete object, we're passing in an object
// that know's how to retrieve the item of that type.
dependencyPropertyValues[property.Name] = binding;
}
protected void SetValue(DependencyProperty property, object value)
{
if (property == null)
throw new ArgumentNullException("You must supply a DependencyProperty object.");
object oldValue = GetValue(property);
if (!Equals(oldValue, value))
{
dependencyPropertyValues[property.Name] = value;
// If the property is supposed to recalculate the the layout of the control call the InvalidateLayout
if (property.Metadata != null && property.Metadata.AffectsLayout)
InvalidateLayout(this);
// Call the change handler for the property if one exists
if (property.Metadata.OnChangeHandler != null)
property.Metadata.OnChangeHandler(this, oldValue, value);
}
}
