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When moving to the mobile platform all applications need to be able to provide different views. Navigating around views in Windows Phone 7 is a very easy thing to do. This post will introduce you to the simplest technique for navigation in Windows Phone 7 apps.
Steps:
1. Create a new Windows Phone Application project.
2. In the MainPage.xaml file copy the following xaml into the ContentGrid Grid:
<StackPanel Orientation="Vertical" VerticalAlignment="Center" >
<TextBox Name="ValueTextBox" Width="200" ></TextBox>
<Button Width="200" Height="30" Content="Next Page" Click="Button_Click"></Button>
</StackPanel>
This gives a text box for the user to enter text and a button to navigate to the next page.
3. Copy the following event handler code to the MainPage.xaml.cs file:
private void Button_Click(object sender, RoutedEventArgs e)
{
NavigationService.Navigate(new Uri( string.Format("/SecondPage.xaml?val={0}", ValueTextBox.Text), UriKind.Relative));
}
The event handler uses the NavigationService.Navigate() function. This is what makes the navigation to another page happen. The function takes a Uri parameter with the name of the page to navigate to and the indication that it is a relative Uri to the current page. Note also the querystring is formatted with the value entered in the ValueTextBox control – in a similar manner to a standard web querystring.
4. Add a new Windows Phone Portrait Page to the project named SecondPage.xaml.
5. Paste the following XAML in the ContentGrid Grid in SecondPage.xaml:
<Button Name="GoBackButton" Width="200" Height="30" Content="Go Back" Click="Button_Click"></Button>
This provides a button to navigate back to the first page.
6. Copy the following event handler code to the SecondPage.xaml.cs file:
private void Button_Click(object sender, RoutedEventArgs e)
{
NavigationService.GoBack();
}
This tells the application to go back to the previously displayed page.
7. Add the following code to the constructor in SecondPage.xaml.cs:
this.Loaded += new RoutedEventHandler(SecondPage_Loaded);
8. Add the following loaded event handler to the SecondPage.xaml.cs file:
void SecondPage_Loaded(object sender, RoutedEventArgs e)
{
if (NavigationContext.QueryString["val"].Length > 0)
MessageBox.Show(NavigationContext.QueryString["val"], "Data Passed", MessageBoxButton.OK);
else
MessageBox.Show("{Empty}!", "Data Passed", MessageBoxButton.OK);
}
This code pops up a message box displaying either the text entered on the first page or the message “{Empty}!” if no text was entered.
9. Run the application, enter some text in the text box and click on the next page button to see the application in action:
Congratulations! You have created a new Windows Phone 7 application with page navigation.
