使用全局类在Windows Phone应用程序中保存数据以用于Windows Phone中的用户设置

Question

I'm a iOS developer starting to learn Windows Phone development. I have a question about saving data in a Windows Phone app like you do with NSUserDefaults in iOS .

I'm developing an app using the Windows Runtime API and not the Silverlight API. I've seen that Silverlight as something called Isolated Storage and Windows runtime API has Application Data Storage .

My question is if somebody with more experience in Windows Phone development and C# could show me and guide me on how to create a global class that I can use to store settings in my Windows Phone app.

In iOS I have a class that uses NSUserDefaults to store and retrive for example if the user is logged in or not etc. It looks like this:

//
//  RPStoreNSUserDefault.m
//
+ (RPStoreNSUserDefault *)sharedInstance
{
    static RPStoreNSUserDefault *shared = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        shared = [[RPStoreNSUserDefault alloc] init];
    });

    return shared;
}

- (void)storeObject:(id)object forKey:(NSString*)key
{
    NSData *serializer = [NSKeyedArchiver archivedDataWithRootObject:object];

    @synchronized(self) {
        [[NSUserDefaults standardUserDefaults] setObject:serializer forKey:key];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }
}

- (id)retrieveObjectForKey:(NSString*)key
{
    NSData *serializer = [[NSUserDefaults standardUserDefaults] objectForKey:key];

    return [NSKeyedUnarchiver unarchiveObjectWithData:serializer];
}

How would I do the same thing using what I understad the Application Data Storage in Windows Phone and c#?

Thanks in advance.

Answer 1

Here's a Storage service I've created for working with WinRT both on Store and Phone.

It uses James Newtons Json.net to serialize and deserialize objects to json before storing them and makes full use of generics.

You might want to look into StorageFile as well. See Jerry Nixons blogpost: http://blog.jerrynixon.com/2012/06/windows-8-how-to-read-files-in-winrt.html

public class StorageService : IStorageService
{
    #region Settings

    public void SaveSetting(string key, string value)
    {
        Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
        localSettings.Values[key] = value;
    }

    public void DeleteSetting(string key)
    {
        Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
        localSettings.Values.Remove(key);
    }

    public string LoadSetting(string key)
    {
        Windows.Storage.ApplicationDataContainer localSettings = Windows.Storage.ApplicationData.Current.LocalSettings;
        var value = localSettings.Values[key];

        if (value == null)
        {
            return null;
        }

        return value.ToString();
    }

    #endregion

    #region Objects

    public async Task<bool> PersistObjectAsync<T>(string key, T value)
    {
        if (string.IsNullOrEmpty(key) || value == null)
        {
            throw new ArgumentNullException();
        }

        Windows.Storage.StorageFolder localFolder =
            Windows.Storage.ApplicationData.Current.LocalFolder;

        string json = JsonConvert.SerializeObject(value, Formatting.Indented);

        var file = await localFolder.CreateFileAsync(key, CreationCollisionOption.ReplaceExisting);
        await FileIO.WriteTextAsync(file, json);

        return true;
    }

    public async Task<T> RetrieveObjectAsync<T>(string key)
    {
        if (string.IsNullOrEmpty(key))
        {
            throw new ArgumentNullException();
        }

        var localFolder = ApplicationData.Current.LocalFolder;

        try
        {
            var file = await localFolder.GetFileAsync(key);
            string json = await FileIO.ReadTextAsync(file);
            return JsonConvert.DeserializeObject<T>(json);
        }
        catch (Exception exp)
        {
            Debug.WriteLine(exp.Message);
            return default(T);
        }
    }

    public async Task<bool> DeleteObjectAsync(string key)
    {
        if (string.IsNullOrEmpty(key))
        {
            throw new ArgumentNullException();
        }

        Windows.Storage.StorageFolder localFolder =
            Windows.Storage.ApplicationData.Current.LocalFolder;

        try
        {
            StorageFile file = await localFolder.GetFileAsync(key);
            await file.DeleteAsync();
            return true;
        }
        catch (Exception exp)
        {
            Debug.WriteLine(exp.Message);
            return false;
        }
    }

    #endregion
}

public interface IStorageService
{
    void SaveSetting(string key, string value);

    void DeleteSetting(string key);

    string LoadSetting(string key);

    Task<bool> PersistObjectAsync<T>(string key, T value);

    Task<T> RetrieveObjectAsync<T>(string key);

    Task<bool> DeleteObjectAsync(string key);
}