Passing a URI to the Windows Runtime
When you use the Windows Runtime in .NET Framework code, the Windows.Foundation.Uri class appears as System.Uri. For example, when you call a Windows Runtime method that takes a Uniform Resource Identifier (URI), IntelliSense displays the parameter type as System.Uri. The System.Uri class allows relative URIs, but the Windows.Foundation.Uri class does not. If you pass a relative URI to a Windows Runtime method, an ArgumentException exception is thrown in your code.
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This is also true for methods you expose in Windows Runtime Components. If your component exposes a method that takes a URI, the signature in your code includes System.Uri. However, to users of your component, the signature includes Windows.Foundation.Uri. A URI that is passed to your component must be an absolute URI. |
Use the Uri.IsAbsoluteUri property to ensure that a URI is absolute before passing it to the Windows Runtime. Using this property is more efficient than catching and handling the ArgumentException exception.
If you want to specify a URI for a resource that your app package contains, you can use the ms-appx or ms-appx-web scheme to create an absolute URI.
The following example shows how to set the Source property for a WebView control and the Source property for an Image control to resources that are contained in a folder named Pages, using both XAML and code.
private void Button_Click_1(object sender, RoutedEventArgs e) { webview1.Source = new Uri("ms-appx-web:///Pages/HTMLPage2.html", UriKind.Absolute); }
<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
<WebView Name="webview1" HorizontalAlignment="Center" Height="222"
VerticalAlignment="Top" Width="310" Margin="472,57,553,0"
Source="ms-appx-web:///Pages/HTMLPage1.html"/>
<Button Content="Button" HorizontalAlignment="Left" Margin="322,185,0,0"
VerticalAlignment="Top" Click="Button_Click_1"/>
<Image HorizontalAlignment="Left" Height="100" Margin="208,123,0,0" VerticalAlignment="Top"
Width="100" Source="ms-appx:///Pages/weather.jpg" />
</Grid>
For more information about these schemes, see URI schemes in the Windows Dev Center.
