c# - How to use lambda statements to initialize UIPropertyMetaData in WPF -

i know basic, i'm not getting it. wish initialize dependency property dashes double collection using lambda operator.

what proper syntax?

thank you.

public static readonly dependencyproperty dashesproperty =         dependencyproperty.register("dashes", typeof(doublecollection), typeof(customtextblock),         new uipropertymetadata(              () =>             {                 doublecollection d = new doublecollection();                 d.add(4);                 d.add(4);                 return d;             }      )); 

first of should avoid passing default value reference types in dp metadata because shared across instances of containing class didn't intend to.

say, declared 2 instances of customtextblock, both instances refer same list , modification in list transparent both instances. unless explicitly setting constructor or somewhere else.

be careful default values of dp reference types.

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anyhow, if still want it, here how done:

new uipropertymetadata(new doublecollection() { 4, 5 }) 

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update:

if pass default value in metadata, doublecollection's gets freezed automatically i.e. can't add/delete collection in case.

var dashescollection = new customtextblock().dashes.add(5); // throw exception. 

however, if set explicitly constructor, it's not marked frozen , items can added/deleted collection.

var dashescollection = new customtextblock().dashes.add(5); // works fine. 

so, essence set value in constructor , not in metadata of dp identifier.