Xamarin中的UserDefault

时间:2015-02-13 22:33:26

标签: c# xamarin

我正在尝试在关闭SettingViewController之前分配文本字段条目,并在URLViewController出现时检查它们。

但是,一旦我检查它,即使用户输入了所有必需的信息,它也会返回null;

// SettingViewController

partial class SettingViewController : UIViewController
    {
        public ServerSettings sSettings;
        public SettingViewController (IntPtr handle) : base (handle)
        {
            this.Title = "Settings";
            this.sSettings = new ServerSettings();

        }

        public override void ViewWillDisappear (bool animated)
        {
            sSettings.server=serverTF.Text;
            sSettings.port = portTF.Text;
            sSettings.password = passwordTF.Text;
            sSettings.userid = inboxuserTF.Text;
            sSettings.username = usernameTF.Text;
        }
    }

// URLViewController

public override void ViewWillAppear(bool animated)
        {
        base.ViewWillAppear (animated);
        SettingViewController callSetting = this.Storyboard.InstantiateViewController ("SettingViewController") as SettingViewController;

        if (callSetting == null)
            throw new Exception("callSetting is null"); // Or if you can handle having a null callSetting then correct for it, but realistically this is a problem, so I'd throw an Exception

        if (callSetting.sSettings == null)
            throw new Exception("sSetting is null"); // Or if you can handle having a null callSetting.sSetting then correct it (such as using a default value).

        if (string.IsNullOrEmpty(callSetting.sSettings.password)==true) 
            Console.WriteLine("is null or empty");
        else 
            Console.WriteLine (callSetting.sSettings.password);

    }

即使用户填写了所有文本字段条目,它也会返回null。 // SettingsViewController enter image description here

// URLViewController enter image description here

1 个答案:

答案 0 :(得分:1)

我会通过使用字典和&来解决这个问题。 userdefaults如下:

在B Viewcontroller中,将用户条目保留在字典中,映射并将其分配给用户默认。

partial class BViewController : UIViewController
{
    const string server = "server";
    const string port = "port";
    const string password = "password";
    const string username = "username";
    const string inboxuserid = "inboxuserid";
    .............
    .............



  public override void ViewWillDisappear (bool animated)
  {
    var appDefaults = new NSDictionary (server, serverTF.Text, port, portTF.Text, password, passwordTF.Text,username,usernameTF.Text, inboxuserid,inboxuserTF.Text);
    NSUserDefaults.StandardUserDefaults.RegisterDefaults (appDefaults);
    NSUserDefaults.StandardUserDefaults.Synchronize ();
  }

}

并在A ViewController中检索它们,如下所示:

partial class AViewController : UIViewController
 {



  public override void ViewWillAppear(bool animated)
   {
    NSUserDefaults.StandardUserDefaults.RegisterDefaults (appDefaults);
    NSUserDefaults.StandardUserDefaults.Synchronize ();
    var username = NSUserDefaults.StandardUserDefaults.StringForKey ("username");
    Console.WriteLine (username);
    }
}

以下链接中也有很好的例子:

https://github.com/xamarin/monotouch-samples/blob/master/AppPrefs/Settings.cs http://forums.xamarin.com/discussion/9089/nsuserdefaults-standarduserdefaults-returns-null-first-time