After I googled for this error for some time, without any luck, I decided t o write a quick blog post about it, just to help others which might have the error due to the same reasons as me.
Today I got this error “XAML Namespace http://schemas.microsoft.com/expression/blend/2008 is not resolved.” in a Silverlight 4 project. I happened right after I added some VisualStates in Blend 4. I could remove the VisualState XAML and everything would then build again fine. As meantioned I googled the error but couldn’t find a solution.
It seems like Blend 4 got a little confused and forgot to add an attribute in XAML for me, which made this error happen. The way I found out were that I saw I had some of the xmlns:d=”…” and xmlns:mc=”…” in my XAML, eventhough I couldn’t remeber I had ever been to Blend with this project. As I knew these are used by Blend to do different stuff, I tried to remove all of thie “Blend” XAML from the top of my UserControl. After that I added the VisualStates again and everything worked. I checked the XAML and it seems like Blend “forgot” to add this little attribute to my UserControl the first time: mc:Ignorable="d"
I guess it got confused as I had some of the “Blend” XAML stuff in my code already.
Just wanted to put this on my blog to help others which might end up with this error :)
I forgive you this time Blend, but don’t let it happen again.