user controls - WPF Set usercontrol property from outside -

my user control has slider. use control in view , want assign value property of outside. this:

<uc:myusercontrol verticalalignment="bottom" margin="8,8,8,0" slider.value="{binding...}"/> 

what syntax ?

thank :)

there no syntax externally reference control within usercontrol; usercontrol black box, , nobody on outside should need know structure.

if need provide property when instantiating usercontrol, declare new dependencyproperty on usercontrol, , bind slider's value property.