ContextMenu Login Screen Windows phone 7

I'm trying to build in .xaml a Context Menu which i can no longer find in my library's so i switched to trying PopUp.

Which seems to be working i just cant view it, i need it to run first thing when my Application Loads because it will work as a log in Screen.

Can any one help me figure out how to Make this visible Right after initialization of the application?

Thank you in advance!

Keeano Martin.

some Code. (.xaml)

<Grid x:Name="ContentGrid" Grid.Row="1">
        <Popup x:Name="loginPopUpwindow" Height="250" Width="300" Margin="1" VerticalAlignment="Bottom" HorizontalAlignment="Center">
            <TextBlock Height="33" HorizontalAlignment="Left" Margin="0,160,0,0" Name="loginTextBlock" Text="Login" VerticalAlignment="Top" Width="474"/>
        </Popup>
        <TextBlock Height="33" HorizontalAlignment="Left" Margin="0,160,0,0" Name="textBlock1" Text="TextBlock" VerticalAlignment="Top" Width="474" />
    </Grid>

(C#)

public MainPage()
    {
        InitializeComponent();
        logi开发者_如何学CnPopUpwindow.IsOpen = true;
    }

In your XAML, did you try

<Popup IsOpen="True"></Popup>

to make it show as soon as the XAML loads?
It works in a desktop program.