Set the URI within the markup:
<HyperlinkButton x:Name="MyButton" TargetName="_blank" Content="Download APK" NavigateUri="/download/ItimHRMSAndroidApp.apk" Canvas.Top="40" Canvas.Left="30"></HyperlinkButton>
And remove the Click
event handler:
private void hyperlinkButton1_Click(object sender, RoutedEventArgs e)
{
Uri myAbsoluteUri = new Uri(Application.Current.Host.Source,"../download/ItimHRMSAndroidApp.apk");
HtmlPage.Window.Navigate(myAbsoluteUri);
}