/// <summary>
/// Returns a dependency object for the given value.
/// </summary>
private static DependencyObject FromObj(object value)
{
// This indirection is necessary to support
// the "association" feature of type descriptor. This feature
// alows one object to mimic the API of another.
return((DependencyObject)TypeDescriptor.GetAssociation(typeof(DependencyObject), value));
}
public void GetAssociationReturnsExpectedObject()
{
var primaryObject = new DescriptorTestComponent();
var secondaryObject = new MockEventDescriptor();
TypeDescriptor.CreateAssociation(primaryObject, secondaryObject);
var associatedObject = TypeDescriptor.GetAssociation(secondaryObject.GetType(), primaryObject);
Assert.IsType(secondaryObject.GetType(), associatedObject);
Assert.Equal(secondaryObject, associatedObject);
}
public void GetAssociationReturnsDesigner()
{
var designer = new MockDesigner();
var designerHost = new MockDesignerHost();
var component = new DescriptorTestComponent();
designerHost.AddDesigner(component, designer);
component.AddService(typeof(IDesignerHost), designerHost);
object associatedObject = TypeDescriptor.GetAssociation(designer.GetType(), component);
Assert.IsType <MockDesigner>(associatedObject);
Assert.Same(designer, associatedObject);
}
public void RemoveSingleAssociation()
{
var primaryObject = new DescriptorTestComponent();
var firstAssociatedObject = new MockEventDescriptor();
var secondAssociatedObject = new MockPropertyDescriptor();
TypeDescriptor.CreateAssociation(primaryObject, firstAssociatedObject);
TypeDescriptor.CreateAssociation(primaryObject, secondAssociatedObject);
TypeDescriptor.RemoveAssociation(primaryObject, firstAssociatedObject);
// the second association should remain
var secondAssociation = TypeDescriptor.GetAssociation(secondAssociatedObject.GetType(), primaryObject);
Assert.Equal(secondAssociatedObject, secondAssociation);
// the first association should not
var firstAssociation = TypeDescriptor.GetAssociation(firstAssociatedObject.GetType(), primaryObject);
Assert.NotEqual(firstAssociatedObject, firstAssociation);
}
public void RemoveAssociationsRemovesAllAssociations()
{
var primaryObject = new DescriptorTestComponent();
var firstAssociatedObject = new MockEventDescriptor();
var secondAssociatedObject = new MockPropertyDescriptor();
TypeDescriptor.CreateAssociation(primaryObject, firstAssociatedObject);
TypeDescriptor.CreateAssociation(primaryObject, secondAssociatedObject);
TypeDescriptor.RemoveAssociations(primaryObject);
// GetAssociation never returns null. The default implementation returns the
// primary object when an association doesn't exist. This isn't documented,
// however, so here we only verify that the formerly associated objects aren't returned.
var firstAssociation = TypeDescriptor.GetAssociation(firstAssociatedObject.GetType(), primaryObject);
Assert.NotEqual(firstAssociatedObject, firstAssociation);
var secondAssociation = TypeDescriptor.GetAssociation(secondAssociatedObject.GetType(), primaryObject);
Assert.NotEqual(secondAssociatedObject, secondAssociation);
}
/// <summary>
/// Returns a collection of properties for our object. We first rely on base
/// CLR properties and then we attempt to match these with dependency properties.
/// </summary>
public PropertyDescriptorCollection GetProperties(Attribute[] attributes)
{
// We have two code paths here based on filtered attributes. An attribute
// filter is just a notificaiton of a filter, it doesn't actually perform
// the filter. Because the default PropertyFilterAttribute is PropertyFilter.All,
// it acts as a nice "don't care" in later filtering stages that TypeDescriptor
// may apply. That means that regardless of the filter value, we don't have
// to fiddle with adding the attribute to the property descriptor.
PropertyFilterOptions filter = PropertyFilterOptions.Valid | PropertyFilterOptions.SetValues;
if (attributes != null)
{
foreach (Attribute attr in attributes)
{
PropertyFilterAttribute filterAttr = attr as PropertyFilterAttribute;
if (filterAttr != null)
{
filter = filterAttr.Filter;
break;
}
}
}
// If no filter is set, or if the only filter is for "invalid" properties,
// there's no work to do.
if (filter == PropertyFilterOptions.None || filter == PropertyFilterOptions.Invalid)
{
return(PropertyDescriptorCollection.Empty);
}
// Value used during filtering. Because direct properties are always
// returned for .Valid and .All, the only case we're directly interested
// in is when filter exactly equals SetValues.
DependencyObject filterValue;
if (filter == PropertyFilterOptions.SetValues)
{
if (_instance == null)
{
return(PropertyDescriptorCollection.Empty);
}
filterValue = (DependencyObject)TypeDescriptor.GetAssociation(_objectType, _instance);
}
else
{
filterValue = null;
}
// Note: For a property filter of "SetValues" it would be ideal if we could use
// DependencyObject's GetLocalValueEnumerator. Unfortunately, we can't:
//
// * We still need to scan properties to get the property descriptor that
// matches the DP.
//
// * The enumerator would skip CLR properties that have no backing DP.
//
// We can still do some optimizations.
// First, have we already discovered properties for this type?
PropertyDescriptorCollection properties = (PropertyDescriptorCollection)_typeProperties[_objectType];
if (properties == null)
{
properties = CreateProperties();
lock (_typeProperties)
{
_typeProperties[_objectType] = properties;
}
}
// Check bit combinations that would yield true in
// any case. For non-attached properties, they're all valid, so if
// the valid bit is set, we're done.
if ((filter & _anySet) == _anySet || (filter & _anyValid) == _anyValid)
{
return(properties);
}
// The filter specifies either set or unset values.
Debug.Assert((filter & _anySet) == filter, "There is a filtering case we did not account for");
List <PropertyDescriptor> newDescriptors = null;
int cnt = properties.Count;
for (int idx = 0; idx < cnt; idx++)
{
PropertyDescriptor prop = properties[idx];
bool shouldSerialize = prop.ShouldSerializeValue(filterValue);
bool addProp = shouldSerialize ^ ((filter & _anySet) == PropertyFilterOptions.UnsetValues);
if (!addProp)
{
// Property should be removed. Make sure our newDescriptors array is
// up to date for where we need to be
if (newDescriptors == null)
{
newDescriptors = new List <PropertyDescriptor>(cnt);
for (int i = 0; i < idx; i++)
{
newDescriptors.Add(properties[i]);
}
}
}
else if (newDescriptors != null)
{
newDescriptors.Add(prop);
}
}
if (newDescriptors != null)
{
properties = new PropertyDescriptorCollection(newDescriptors.ToArray(), true);
}
return(properties);
}
