c# - Two-way binding in AvalonEdit doesn't work -

c# - Two-way binding in AvalonEdit doesn't work -

i have used avalonedit in project based on wpf , mvvm. after reading this post created next class:

public class mvvmtexteditor : texteditor, inotifypropertychanged { public static dependencyproperty documenttextproperty = dependencyproperty.register("documenttext", typeof(string), typeof(mvvmtexteditor), new propertymetadata((obj, args) => { mvvmtexteditor target = (mvvmtexteditor)obj; target.documenttext = (string)args.newvalue; }) ); public string documenttext { { homecoming base.text; } set { base.text = value; } } protected override void ontextchanged(eventargs e) { raisepropertychanged("documenttext"); base.ontextchanged(e); } public event propertychangedeventhandler propertychanged; public void raisepropertychanged(string info) { if (propertychanged != null) { propertychanged(this, new propertychangedeventargs(info)); } } }

and used next xaml utilize control:

<avalonedit:mvvmtexteditor x:name="xmlmessage"> <avalonedit:mvvmtexteditor.documenttext> <binding path ="messagexml" mode="twoway" updatesourcetrigger="propertychanged"> <binding.validationrules> <local:xmlmessagevalidationrule /> </binding.validationrules> </binding> </avalonedit:mvvmtexteditor.documenttext> </avalonedit:mvvmtexteditor>

but binding works oneway , doesn't update string property nor run validation rule.

how can prepare binding work expected twoway?

wpf bindings not utilize documenttext property; instead access underlying value of dependency property directly.

your ontextchanged method doesn't alter value of underlying dependency property. need re-create value base.text dependency property on every change:

protected override void ontextchanged(eventargs e) { setcurrentvalue(documenttextproperty, base.text); base.ontextchanged(e); }

this issue easier see if followed right pattern implementing dependencyproperty: documenttext property should utilize getvalue/setvalue methods, , not access different backing store.

c# wpf data-binding dependency-properties avalonedit