C＃MVVM使用NotifyIcon从代码背后调用ViewModel方法

Question

I can't seem to get a method in my ViewModel to run successfully from my XAML code behind when using NotifyIcon. The method executes correctly, as tested with debugging mode using breakpoints, but nothing happens in the View.

The method in question is RefreshData, and it can be called from either a button in the View (works as expected), or from right clicking the NotifyIcon and selecting Refresh Data (does nothing). I'll post relevant code below. Any help would be appreciated!

MainWindow constructor in CodeBehind

public MainWindow()
    {
        try
        {
            MM = new MMViewModel();
            InitializeComponent();                
            DataContext = MM;

            _notifyIcon = new NotifyIcon();
            _notifyIcon.DoubleClick += (s, args) => ShowMainWindow(this);
            _notifyIcon.Icon = Migration_Monitor_v2.Properties.Resources.mmc;
            _notifyIcon.Visible = true;

            Closing += MainWindow_Closing;

            CreateContextMenu();
        }
        catch (Exception e)
        {
            logger.Error("App failed with exception: ", e);
        }
    }

    private void CreateContextMenu()
    {
        _notifyIcon.ContextMenuStrip = new ContextMenuStrip();
        _notifyIcon.ContextMenuStrip.Items.Add("Refresh Data").Click += (s,e) => MM.RefreshData();
        _notifyIcon.ContextMenuStrip.Items.Add("Exit").Click += (s, e) => ExitApplication(this);
    }

RefreshData method in ViewModel (works when executed from the Refresh button in the View)

    public void RefreshData()
    {
        InfoPanelVisible = Visibility.Hidden;
        InfoSummaryVisible = Visibility.Visible;
        Task.Run(() => LoadData());
        n = DateTime.Now;
        ProgressBarText = "Click a project to show progress";
        ProgressBarValue = 0;
        lastRefresh.Reset();
        lastRefresh.Start();
    }

LoadData method (and associated methods) called from RefreshData

    public async void LoadData()
    {
        IsLoading = Visibility.Visible;
        await GetWebApiInfo();
        MonitorData downloadInfo = main;
        try { AssignDataToControls(downloadInfo); }
        catch (Exception e) { Console.WriteLine("Error: " + e); }
        finally { IsLoading = Visibility.Hidden; }
    }

    public void AssignDataToControls(MonitorData mon)
    {
        MainPanel.Clear();
        MonitorText.Clear();
        mon.MainPanel.ToList().ForEach(x => MainPanel.Add(x));
        mon.MonitorText.ToList().ForEach(x => MonitorText.Add(x));
        Information = mon.Information;
        ProgressData = mon.progList;
    }

    public async Task GetWebApiInfo()
    {
        var url = "::::WEB API ADDRESS::::";
        string responseFromServer;
        using (HttpClient _client = new HttpClient())
        using (var dataStream = await _client.GetStreamAsync(url))
        using (var reader = new StreamReader(dataStream, Encoding.Unicode))
            responseFromServer = await reader.ReadToEndAsync();
        var deserializer = new JavaScriptSerializer();
        main = deserializer.Deserialize<MonitorData>(responseFromServer);
    } 

RefreshCommand from ViewModel Commands.cs file

internal class RefreshCommand : ICommand 
{
    public RefreshCommand(MMViewModel viewModel)
    {
        _viewModel = viewModel;
    }

    private MMViewModel _viewModel;

    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }

    public bool CanExecute(object parameter)
    {
        return _viewModel.CanRefresh;
    }

    public void Execute(object parameter)
    {
        _viewModel.RefreshData();
    }
}

Answer 1

Solved this issue. The problem was that my ViewModel was being constructed three separate times, so it was unclear to the command which instance was being referenced.

To fix this, I removed references to the ViewModel in my XAML Window definition space. There were 2 references I thought I needed for the ViewModel as a local namespace (ie x:local.VM="MM.MyViewModel"). After removing those, the ViewModel is only being constructed once and all code is running as intended. Thanks to @Will for his help getting to the bottom of this!