WPF Dependency property ,overrideMetaData issue

Seemstoknow，becauseMyStackPanel2hasregister,sowillnewaproperty,_metaMaphasnobasetype'smetadata,soifweuse：

staticMyStackPanel2()

{

MyStackPanel.IntDataProperty.OverrideMetadata(typeof(MyStackPanel2),newFrameworkPropertyMetadata(9));

MyStackPanel.MinDateProperty.AddOwner(typeof(MyStackPanel2),newFrameworkPropertyMetadata(DateTime.Now,onMindateChange2));

}

Thenewmetadatawillmergebasetype'smetadata!Forattachedproperty,althoughregister’smetaDataisonlystoredatdefaultmetaData，_metaMaphaveno，butoverrideMetaDatamethodwilladdnewmetadatato_metaMap,andwilldomergetoo.

And,MyStackPanel2issubclassofMyStackPanel,sothemergewillhappen,ifnotsubclass,themergewillnothappeneither.likethecodebelow:

publicpartialclassUserControlLabel:Label

{

staticUserControlLabel()

{

MyStackPanel.MinDateProperty.OverrideMetadata(typeof(UserControlLabel),newFrameworkPropertyMetadata(DateTime.Now,onMinDateChangeUserControl));

}

publicDateTimeMinDate

{

get{return(DateTime)GetValue(MyStackPanel.MinDateProperty);}

set{SetValue(MyStackPanel.MinDateProperty,value);}

}

}

2.

ThisPropertyFromNamehashtableismainlyusebythexaml->codeprocess

whichcanbefoundbyanalyzingtheDependencyProperty.FromName()methodusingreflector’s“useby”function..

3.attchedpropertyregisternotuseoverridemetedata,becauseitsownertypecannotbedependencyObject,_metadataMapneedtouse

DependencyObjectType.typeIdaskey.