c# - wpf Custom panel xaml name is not declared in namespace -

i made custom panel, customcanvas class enxtending canvas class in namespace canvase. , add

xmlns:local="clr-namespace:canvase"

and

<stackpanel>                               <local:customcanvas x:name="customcanvas" maxheight="1555">                             </local:customcanvas>  </stackpanel> 

then show

name "customcanvas" not declared in namespace "clr-namespace:canvase"

so, don't see wpf design view, wysiwyg.

please help

make sure platform target project (project properties -> build) set cpu.