private bool OnBeforeRemoveItemEvent(AttributeDefinition item)
{
BeforeRemoveItemEventHandler ae = this.BeforeRemoveItem;
if (ae != null)
{
AttributeDefinitionDictionaryEventArgs e = new AttributeDefinitionDictionaryEventArgs(item);
ae(this, e);
return(e.Cancel);
}
return(false);
}
protected virtual bool OnBeforeAddItemEvent(AttributeDefinition item)
{
BeforeAddItemEventHandler ae = BeforeAddItem;
if (ae != null)
{
AttributeDefinitionDictionaryEventArgs e = new AttributeDefinitionDictionaryEventArgs(item);
ae(this, e);
return(e.Cancel);
}
return(false);
}
private void AttributeDefinitions_RemoveItem(AttributeDefinitionDictionary sender, AttributeDefinitionDictionaryEventArgs e)
{
if (this.readOnly) return;
this.OnAttributeDefinitionRemovedEvent(e.Item);
e.Item.Owner = null;
if(this.attributes.Count == 0)
this.flags &= ~BlockTypeFlags.NonConstantAttributeDefinitions;
}
private void AttributeDefinitions_ItemAdd(AttributeDefinitionDictionary sender, AttributeDefinitionDictionaryEventArgs e)
{
if (this.readOnly) return;
this.OnAttributeDefinitionAddedEvent(e.Item);
e.Item.Owner = this;
// the block has attributes
this.flags |= BlockTypeFlags.NonConstantAttributeDefinitions;
}
private void AttributeDefinitions_BeforeRemoveItem(AttributeDefinitionDictionary sender, AttributeDefinitionDictionaryEventArgs e)
{
// only attribute definitions owned by the actual block can be removed
e.Cancel = !ReferenceEquals(e.Item.Owner, this) || this.readOnly;
}
private void AttributeDefinitions_BeforeAddItem(AttributeDefinitionDictionary sender, AttributeDefinitionDictionaryEventArgs e)
{
// null, attributes with the same tag, and attribute definitions already owned by another Block are not allowed in the attributes list.
if (e.Item == null)
e.Cancel = true;
else if (this.attributes.ContainsTag(e.Item.Tag))
e.Cancel = true;
else if (this.readOnly)
e.Cancel = true;
else if (e.Item.Owner != null)
{
// if the block does not belong to a document, all attribute definitions which owner is not null will be rejected
if (this.Record.Owner == null)
e.Cancel = true;
// if the block belongs to a document, the entity will be added to the block only if both, the block and the attribute definitions document, are the same
// this is handled by the BlocksRecordCollection
}
else
e.Cancel = false;
}