C＃Windows 8应用程序创建文件

Question

I'm trying to create a file then write to the file and read from it as well... kind of like settings for my app to load every time it loads. Why is this not working for me? I'm running visual studio 2012 and I think when I run the program there the file should be created in the project's folder... my method it's async and void... don't really know what is going on haha

 StorageFile sampleFile = await Windows.Storage.ApplicationData.Current.LocalFolder.CreateFileAsync("config.txt", CreationCollisionOption.ReplaceExisting);

How can I create this in the local folder? so every time the program runs no matter in what computer it will create the file and load it when the user close and re-open the program?

Answer 1

Man, great question!

Here's the exact logic to do what you are asking:

public class MyData
{
    public string Title { get; set; }
}

public sealed partial class MainPage : Page
{
    public MainPage()
    {
        this.InitializeComponent();
    }

    protected async override void OnNavigatedTo(NavigationEventArgs e)
    {
        this.DataContext = await LoadData();
    }

    protected override void OnNavigatedFrom(NavigationEventArgs e)
    {
        SaveData(this.DataContext as MyData);
        base.OnNavigatedFrom(e);
    }

    private async Task<MyData> LoadData()
    {
        var _Data = await StorageHelper.ReadFileAsync<MyData>(
            this.GetType().ToString(), StorageHelper.StorageStrategies.Local);
        return _Data ?? new MyData() { Title = "Welcome" };
    }

    private async void SaveData(MyData data)
    {
        await StorageHelper.WriteFileAsync(
            this.GetType().ToString(), data, StorageHelper.StorageStrategies.Local);
    }
}

The StorageHelper class can be found here . or on my blog http://jerrynixon.com

Best of luck!

Answer 2

How can I create this in the local folder?

You can't, and anyway you're not supposed to... Windows Store apps run in a sandbox, they have a very restricted access to the file system. Basically, you have access to:

• your app's LocalFolder (which is not the installation folder) and RoamingFolder
• documents library, pictures library, music library, etc, depending on your app's capabilities (declared in the app manifest)
• files selected by the user using a file picker

And I think that's about it... You can also access the files in the installation folder ( Package.Current.InstallationFolder ), but only for reading.