如何从WP7中的RSS文件获取图像和文本？

Question

I am trying to get RSS text with its Image but image couldn't show i would view model for getting image and use simple RSS technique to get image would you tell me how to get both image and text....... Here is my XAML code:

<ListBox Name="lstRSS" ItemsSource="{Binding FeedItems}" DataContext="{StaticResource MainViewModel}" FontSize="30" Grid.Row="1">
    <ListBox.ItemTemplate>
        <DataTemplate>
             <Grid Height="700">
                    <TextBlock Text="{Binding Path=Title}"></TextBlock>
                    <UserControls:Loader Width="100" Height="100" />
                    <Image Source="{Binding Link}" Width="450" Height="350" />
             </Grid>
        </DataTemplate>
   </ListBox.ItemTemplate>
   <ListBox.ItemsPanel>
       <ItemsPanelTemplate>
           <VirtualizingStackPanel />
        </ItemsPanelTemplate>

    </ListBox.ItemsPanel>
</ListBox>

Answer 1

You cannot bind to a URL in that way as a String/Uri is not a valid value for the Image.Source property. If a constant URL is set in xaml then the image will be shown correctly as the compiler generated code takes the URL and converts it to a BitmapSource.

To bind an image URL in that fashion you will need a converter . The converter can take the URL and convert it to a BitmapImage:

public class UriToImageConverter : IValueConverter
{

    #region IValueConverter Members

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        // This could be extended to accept a Uri as well
        string url = value as string;
        if (!string.IsNullOrEmpty(url))
        {
            return new BitmapImage(new Uri(url, UriKind.RelativeOrAbsolute));
        }
        else
        {
            return null;
        }
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }

    #endregion
}

You then need to add an instance of this class to the apps resources (in app.xaml or in the page xaml):

<local:UriToImageConverter x:Key="ImageConverter"/>

You can then set the binding like this:

<Image Source="{Binding Link, Converter={StaticResource ImageConverter}}" />