Hi iv'e read your tutorial and downloaded some samples. but I can't get it work when I add the sorce code here:

<UserControl x:Class="SilverlightApplication1.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:game="clr-namespace:Zombie_Mash_v1"
    Width="400" Height="300" >
    <Grid x:Name="LayoutRoot" Background="White">
        <Canvas>
            <game:Game1 x:Name="game"/>
        </Canvas>
    </Grid>
</UserControl>

 

It worked first. But than, I edited another application and suddenly it stopped working. It says there is nothing called like that.  Sad