Some time you want to make your app more user friendly by automatically focus on specify control for example search text box so that when user open the page, they can start typing the keyword they want to search rather than click on the search text box first then only start typing.

I try to use TextBox.Focus() in OnNavigatedTo, but it nothing happen. So I try to use the same method use in Silverlight by creating a DispatcherTimer and delay the focus by 0.5 second. Well, this method work out in Windows Store App. If you are interested, below are the code.

// timer to create initial focus on control
DispatcherTimer initialFocusDispatcherTimer = new DispatcherTimer();
initialFocusDispatcherTimer.Interval = new TimeSpan(0, 0, 0, 0, 500);
initialFocusDispatcherTimer.Tick += (tickSender, tickEvent) =>
    {
        initialFocusDispatcherTimer.Stop();

    // focus on search bar
    SearchTextBox.Focus(Windows.UI.Xaml.FocusState.Keyboard);
    };
initialFocusDispatcherTimer.Start();

by Ooi Keng Siang via Ooiks’s Blog

Before Windows 8, to check a file exist or not on Windows Phone 7.5 or .NET can be as simple as calling the file.IsFileExist() and it will return a simple boolean indicated whatever the file exist or not. But Windows 8 team decided to have a totally different way and I had no idea why Microsoft or Windows 8 team decided to re-write it.

Anyway, here is how it work out in Windows 8 app (C# code):

public async Task<bool> IsFileExist(string path)
{
    try
    {
        await Windows.Storage.StorageFile.GetFileFromPathAsync(path);

        // file found
        return (true);
    }
    catch
    {
        // file not found
        return (false);
    }
}

by Ooi Keng Siang via Ooiks’s Blog