Unexpected Behaviour with WPF Datagrid Grouping with DateTimePicker control -

inside window, have simple datagrid control datetimepicker column, , textbox column. group rows inside datagrid month-year string derived datetimepicker. here xaml columns , grouping.....

                <datagridtemplatecolumn header="date" width="100">                 <datagridtemplatecolumn.celltemplate>                     <datatemplate>                         <xctk:datetimepicker isenabled="true" format="custom" formatstring="m/d/yyyy h:mm" value="{binding thedate, updatesourcetrigger=propertychanged, mode=twoway}"/>                     </datatemplate>                 </datagridtemplatecolumn.celltemplate>             </datagridtemplatecolumn>             <datagridtemplatecolumn header="text" width="150">                 <datagridtemplatecolumn.celltemplate>                     <datatemplate>                         <textbox textwrapping="wrap" acceptsreturn="true" maxlines="2" verticalscrollbarvisibility="auto" maxlength="150" text="{binding thetext, updatesourcetrigger=lostfocus, mode=twoway}"></textbox>                     </datatemplate>                 </datagridtemplatecolumn.celltemplate>             </datagridtemplatecolumn>             <datagrid.groupstyle>             <groupstyle>                 <groupstyle.headertemplate>                     <datatemplate>                         <stackpanel>                             <textblock text="{binding name}" fontweight="bold" padding="3"/>                         </stackpanel>                     </datatemplate>                 </groupstyle.headertemplate>             </groupstyle>         </datagrid.groupstyle> 

i have simple class text string, , datetimepicker datetime, , string month-year create dynamically. here c# code class...

public datetime duedate { get; set; } public string task { get; set; }  private string _monthyear; public string monthyear {     { return duedate.month.tostring() + " - " + duedate.year.tostring(); } } 

here initialization of grouping

mycollectionview = collectionviewsource.getdefaultview(myobservablecollectionlist); mycollectionview.groupdescriptions.add(new propertygroupdescription("monthyear"));  mydatagrid.itemssource = mycollectionview; // in case, myobservablecollectionlist observable collection holds datagrid  // rows. mycollectionview icollectionview object 

everything working except 1 annoying piece of unexpected behavior. don't know if bug datetimepicker control extended wpf toolkit.

whenever change month or year on datetimepicker control , click on new row or different column in same row, row changed date not grouped remain inside old month-year date group until sort it. behavior fine if consistent however...

if change month or year on datetimepicker control, , tab through or click through same datetimepicker control (not changing anything), , click on new row, old row grouped new month - year category.

i'm not sure feel bug datetimepicker control it's calling sort of event when tab through control if don't change date. right i'm pretty confused, , wondering if has insight why happening.

*note** have tested , without inotifypropertychanged, have interface implemented, , behavior occurs , without implemented thought leave out simplicity sake.

any appreciated thank you!

i have fixed issue, caused uses of both _monthyear monthyear, guess whenever change date, there multiple calls change _monthyear. whatever reason, i'm assuming group description...

taskschedulecollection.groupdescriptions.add(new propertygroupdescription("monthyear")); 

maybe mixed in valuechanged or similar event inside datetimepicker cause grouping re apply , new row groups created(i'm not 100% sure this).

i fixed issue removing _monthyear property unnecessary , keeping single monthyear property dependent on date.

    public string monthyear     {         { return _date.month.tostring() + " - " + _date.year.tostring(); }     } 

the grouping reapplys whenever sort list collection, consistent behavior want.