Error with TextBox control template

i'm trying edit textbox control template, when paste template http://msdn.microsoft.com/en-us/library/cc645035(v=vs.95).aspx i error on line indicated:

<storyboard>

<objectanimationusingkeyframes storyboard.targetname="validationtooltip" storyboard.targetproperty="ishittestvisible">

<discreteobjectkeyframe keytime="0">

<discreteobjectkeyframe.value>

<sys:boolean>true</sys:boolean>  <!-- error here sys:boolen not found -->

</discreteobjectkeyframe.value>

</discreteobjectkeyframe>

</objectanimationusingkeyframes>

</storyboard>

i'm including namespace artice required.

any ideas?

hi michaell...,

you'd better add this reference in xaml file.

xmlns:sys="clr-namespace:system;assembly=mscorlib" 

we highly recommend use blend edit template.  mush easier ui related work.  thanks.

best regards,

jonathan

Silverlight  >  Getting Started with Silverlight