Passing data to Navigation Pages

1. Begin by opening the project NavAppFromScratch you were working on in the previous section.

2. Open the xaml for View1.xmal and modify the source to include a ComboBox under the Button:

　<Combobox Padding="10"  Margin="10" x:Name="Color" Width="100">

　　<ComboBoxItem Content="Blue" IsSelected="True" />

　　<ComboBoxItem Content="Red" />

　　<ComboBoxItem Content="Green" />

　</ComboBox>

3. Next open the code behind for View1.xaml and edit the Button_Click event handler to pass the selected color in the querystring of the Uri passed to the Navigate method:

private void Button_Click(object sender, RoutedEventArgs e)

{

　　string color=this.Color.SelectionBoxItem.ToString();

　　NavigateionService.Navigate(new Uri(string.Format("/InnverView1.xmal?Color={0}",color),UriKind.Relative));

}

4. Open the InnverView1.xaml file and add a second TextBlock below the existing TextBlock using a stackPanel:

<Grid x:Name="LayoutRoot">

　　<StackPanel Orientation="Vertical">

　　　　<TextBlock Text="Inner View 1" x:Name="ViewHeader" FontSize="40" Foreground="Blue" HorizontalAlignment="Center" VerticalAlignment="Center" />

　　　　<TextBlock Text="(Blue)" x:Name="ViewColor" FontSize="30" Foreground="Blue" HorizontalAlignment="Center" VerticalAlignment="Center" />

　　</StackPanel>

</Grid>

5. Open the code behind for InnerView1.xaml and retrieve the passed color using the Navigationcontext object. Then add a switch statement to change the color of the TextBlocks and edit the Text for the second TextBlock:

protected override void OnNavigatedTo(NavigationEventArgs e)

{

　　string color=NavigationContext.Querystring["Color"].ToString();　　

　　Brush b;

　　switch(color)

　　{

　　　　case "Red":

　　　　　　b = new SolidColorBrush(Color.FromArgb(255,255,0,0));

　　　　　　ViewHeader.Foreground=b;

　　　　　　ViewColor.Foreground=b;

　　　　　　ViewColor.Text="(Red)";

　　　　　　break;

　　　　case "Green":

　　　　　　b = new SolidColorBrush(Color.FromArgb(255,0,255,0));

　　　　　　ViewHeader.Foreground=b;

　　　　　　ViewColor.Foreground=b;

　　　　　　ViewColor.Text="(Green)";

　　　　　　break;

　　　　default:

　　　　　　b = new SolidColorBrush(Color.FromArgb(255,0,0,255));

　　　　　　ViewHeader.Foreground=b;

　　　　　　ViewColor.Foreground=b;

　　　　　　ViewColor.Text="(Blue)";

　　　　　　break;

}

}