C# Helpers.Binding类代码示例

        protected virtual void SetupBindings()
        {
            _isConnectedBinding = this.SetBinding(() => DeviceVm.IsConnected).WhenSourceChanges(() =>
                {
                    System.Diagnostics.Debug.WriteLine("SubDeviceViewControllerBase: DeviceViewModel PropertyChanged IsConnected");

                    var navService = ServiceLocator.Current.GetInstance<INavigationService>();
                    if (!DeviceVm.IsConnected && navService.CurrentPageKey == _viewPageKey)
                    {
                        System.Diagnostics.Debug.WriteLine("Navigating back since device is not connected anymore.");
                        navService.GoBack();
                    }
                });
            _isConnectedBinding.ForceUpdateValueFromSourceToTarget();

            _programModeBinding = this.SetBinding(() => DeviceVm.ProgramMode).WhenSourceChanges(() =>
                {
                    System.Diagnostics.Debug.WriteLine("SubDeviceViewControllerBase: DeviceViewModel PropertyChanged ProgramMode");

                    var navService = ServiceLocator.Current.GetInstance<INavigationService>();
                    if (_programMode != MoCoBusProgramMode.Invalid && DeviceVm.ProgramMode != _programMode && navService.CurrentPageKey == _viewPageKey)
                    {
                        System.Diagnostics.Debug.WriteLine("Navigating back since ProgramMode was changed to another mode");
                        navService.GoBack();
                    }
                });
            _programModeBinding.ForceUpdateValueFromSourceToTarget();
        }

        public void SetCommand_OnBarButtonWithBinding_ParameterShouldUpdate()
        {
            var value = DateTime.Now.Ticks.ToString();

            var vmSource = new TestViewModel
            {
                Model = new TestModel
                {
                    MyProperty = value
                }
            };

            var vmTarget = new TestViewModel();

            var control = new UIBarButtonItemEx();

            var binding = new Binding<string, string>(
                vmSource,
                () => vmSource.Model.MyProperty);

            control.SetCommand(
                "Clicked",
                vmTarget.SetPropertyCommand,
                binding);

            Assert.IsNull(vmTarget.TargetProperty);
            control.PerformEvent();
            Assert.AreEqual(value, vmTarget.TargetProperty);

            value += "Test";
            vmSource.Model.MyProperty = value;
            control.PerformEvent();
            Assert.AreEqual(value, vmTarget.TargetProperty);
        }

        public void Binding_Test1_Error()
        {
            Vm = new AccountViewModel();

#if ANDROID
            Operation = new EditText(Application.Context);
            ChildName = new EditText(Application.Context);
#elif __IOS__
            Operation = new UITextView();
            ChildName = new UITextView();
#endif

            _binding1 = this.SetBinding(
                () => Vm.FormattedOperation,
                () => Operation.Text);

            _binding2 = this.SetBinding(
                () => Vm.AccountDetails.Name,
                () => ChildName.Text,
                fallbackValue: "Fallback",
                targetNullValue: "TargetNull");

            Assert.AreEqual(AccountViewModel.EmptyText, Operation.Text);
            Assert.AreEqual(_binding2.FallbackValue, ChildName.Text);

            Vm.SetAccount();

            Assert.AreEqual(
                AccountViewModel.NotEmptyText + Vm.AccountDetails.Balance + Vm.Amount,
                Operation.Text);
            Assert.AreEqual(Vm.AccountDetails.Name, ChildName.Text);
        }

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            SetContentView(Resource.Layout.AddComment);

            // Retrieve navigation parameter and set as current "DataContext"
            Vm = GlobalNavigation.GetAndRemoveParameter<FlowerViewModel>(Intent);

            // Avoid aggressive linker problem which removes the TextChanged event
            CommentText.TextChanged += (s, e) =>
            {
            };

            _saveBinding = this.SetBinding(
                () => CommentText.Text);

            // Avoid aggressive linker problem which removes the Click event
            SaveCommentButton.Click += (s, e) =>
            {
            };

            SaveCommentButton.SetCommand(
                "Click",
                Vm.SaveCommentCommand,
                _saveBinding);
        }

        public void Binding_ConverterWithFallbackValue_ErrorInConverterShouldUseFallbackValue()
        {
            var vmSource = new TestViewModel
            {
                Model = new TestModel
                {
                    MyProperty = "Initial value"
                }
            };

            var vmTarget = new TestViewModel();

            const string fallbackValue = "Fallback value";
            const string targetNullValue = "Target null value";

            _binding = new Binding<string, string>(
                vmSource,
                () => vmSource.Model.MyProperty,
                vmTarget,
                () => vmTarget.TargetProperty,
                BindingMode.Default,
                fallbackValue,
                targetNullValue)
                .ConvertSourceToTarget(
                    value =>
                    {
                        throw new InvalidCastException("Only for test");
                    });

            Assert.AreEqual(fallbackValue, vmTarget.TargetProperty);

            vmSource.Model.MyProperty = "New value";

            Assert.AreEqual(fallbackValue, vmTarget.TargetProperty);
        }

        public void Binding_MultipleLevelsOfNull_ShouldUseFallbackValueThenTargetNullValue()
        {
            var vmSource = new TestViewModel();
            var vmTarget = new TestViewModel();

            const string fallbackValue = "Fallback value";
            const string targetNullValue = "Target null value";

            _binding = new Binding<string, string>(
                vmSource,
                () => vmSource.Nested.Model.MyProperty,
                vmTarget,
                () => vmTarget.TargetProperty,
                BindingMode.Default,
                fallbackValue,
                targetNullValue);

            Assert.AreEqual(fallbackValue, vmTarget.TargetProperty);
            vmSource.Nested = new TestViewModel();
            Assert.AreEqual(fallbackValue, vmTarget.TargetProperty);
            vmSource.Nested.Model = new TestModel();
            Assert.AreEqual(targetNullValue, vmTarget.TargetProperty);
            vmSource.Nested.Model.MyProperty = DateTime.Now.Ticks.ToString();
            Assert.AreEqual(vmSource.Nested.Model.MyProperty, vmTarget.TargetProperty);
        }

        public void Binding_TwoWayFromEditTextToEditTextWithObserveEvent_BindingGetsUpdated()
        {
            var control1 = new EditText(Application.Context);
            var control2 = new EditText(Application.Context);

            var binding = new Binding<string, string>(
                control1,
                () => control1.Text,
                control2,
                () => control2.Text,
                BindingMode.TwoWay)
                .ObserveSourceEvent<View.LongClickEventArgs>("LongClick")
                .ObserveTargetEvent<View.LongClickEventArgs>("LongClick");

            Assert.AreEqual(string.Empty, control1.Text);
            Assert.AreEqual(control1.Text, control2.Text);
            var value = DateTime.Now.Ticks.ToString();
            control1.Text = value;
            Assert.AreEqual(value, control1.Text);
            Assert.AreEqual(string.Empty, control2.Text);
            control1.PerformLongClick();
            Assert.AreEqual(control1.Text, control2.Text);

            var newValue = value + "Suffix";
            control2.Text = newValue;
            Assert.AreEqual(newValue, control2.Text);
            Assert.AreEqual(value, control1.Text);
            control2.PerformLongClick();
            Assert.AreEqual(control2.Text, control1.Text);
        }

        protected virtual void DetachBindings()
        {
            _isConnectedBinding?.Detach();
            _isConnectedBinding = null;

            _programModeBinding?.Detach();
            _programModeBinding = null;
        }

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();

            // Set bindings
            NameBinding = this.SetBinding(() => NoteViewModel.CurrentNote.Title, () => lblTitle.Text);
            DateBinding = this.SetBinding(() => NoteViewModel.CurrentNote.DateString, () => lblDate.Text);
            ContentBinding = this.SetBinding(() => NoteViewModel.CurrentNote.Content, () => lblContent.Text);
        }

        public void SetViewModel (LogTimeEntriesViewModel viewModel)
        {
            ViewModel = viewModel;

            // TODO: investigate why WhenSourceChanges doesn't work. :(
            isRunningBinding = this.SetBinding (() => ViewModel.IsTimeEntryRunning, () => IsRunning);
            durationBinding = this.SetBinding (() => ViewModel.Duration, () => DurationTextView.Text);
            descBinding = this.SetBinding (() => ViewModel.Description, () => DescriptionTextView.Text)
                          .ConvertSourceToTarget (desc => desc != string.Empty ? desc : activity.ApplicationContext.Resources.GetText (Resource.String.TimerComponentNoDescription));
            projectBinding = this.SetBinding (() => ViewModel.ProjectName, () => ProjectTextView.Text)
                             .ConvertSourceToTarget (proj => proj != string.Empty ? proj : activity.ApplicationContext.Resources.GetText (Resource.String.TimerComponentNoProject));
        }

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);

           
            // Get our button from the layout resource,
            // and attach an event to it
            ButtonGet = FindViewById<Button>(Resource.Id.myButton);
            UsernameText = FindViewById<EditText>(Resource.Id.username);
            PasswordText = FindViewById<EditText>(Resource.Id.password);
            ComboText = FindViewById<TextView>(Resource.Id.combo);
            ProgressBar = FindViewById<ProgressBar>(Resource.Id.progressBar1);


            //So things don't link out. 
            //Only needed if linking all
            //UsernameText.TextChanged += (sender, e) => {};
            //PasswordText.TextChanged += (sender, e) => {};
            //ButtonGet.Click += (sender, e) => {};

            ButtonGet.SetCommand("Click", VM.GetPeopleCommand);

            unBind = this.SetBinding(() => VM.Username, 
                () => UsernameText.Text,
                BindingMode.TwoWay);

            passBind = this.SetBinding(() => VM.Password, 
                () => PasswordText.Text,
                BindingMode.TwoWay);

            combBind = this.SetBinding(() => VM.ComboDisplay,
                () => ComboText.Text,
                BindingMode.OneWay);

            busyBind = this.SetBinding(() => VM.IsBusy).WhenSourceChanges(() =>
                {
                    ButtonGet.Enabled = !VM.IsBusy;
                    if(VM.IsBusy)
                        ProgressBar.Visibility = ViewStates.Visible;
                    else
                        ProgressBar.Visibility = ViewStates.Invisible;
                });

            updatedBind = this.SetBinding(() => VM.People)
                .WhenSourceChanges(() =>
                    {
                        RunOnUiThread(() =>Toast.MakeText(this, "Count: " + VM.People.Count, ToastLength.Short).Show()); 

                    });
        }

        public AndroidNotificationManager ()
        {
            ctx = ServiceContainer.Resolve<Context> ();
            notificationManager = (NotificationManager)ctx.GetSystemService (Context.NotificationService);
            runningBuilder = CreateRunningNotificationBuilder (ctx);
            idleBuilder = CreateIdleNotificationBuilder (ctx);
            propertyTracker = new PropertyChangeTracker ();

            TimeEntryManager = ServiceContainer.Resolve<ActiveTimeEntryManager> ();
            binding = this.SetBinding (() => TimeEntryManager.ActiveTimeEntry).WhenSourceChanges (OnActiveTimeEntryChanged);

            var bus = ServiceContainer.Resolve<MessageBus> ();
            subscriptionSettingChanged = bus.Subscribe<SettingChangedMessage> (OnSettingChanged);
        }

        public override void ViewDidLoad()
        {
            View = new UniversalView();
            base.ViewDidLoad();
            InitializeComponent();

            Title = "Add comment";

            _commentBinding = this.SetBinding(
                () => CommentText.Text)
                .UpdateSourceTrigger("Changed");

            SaveCommentButton.SetCommand("Clicked", Vm.SaveCommentCommand, _commentBinding);
        }

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);

            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.Main);

            _messageBinding = this.SetBinding(() => EditMessage.Text, BindingMode.TwoWay);

            MessageButton.SetCommand("Click", Vm.MessageCommand, _messageBinding);

            _textViewBinding = this.SetBinding(() => Vm.PreviousMessage, () => PreviousMessage.Text);

        }

    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

        // Set our view from the "main" layout resource
        SetContentView(Resource.Layout.Main);

        // Get our button from the layout resource,
        // and attach an event to it

        CommandButton.SetCommand("Click", ViewModel.ShowDialogCommand);

        _messageBinding = this.SetBinding(() => ViewModel.Message, () => MessageView.Text, BindingMode.OneWay);
    }