如何将WPF应用代码整合到MVVM并关联内部变量与Model属性？

我开发了一个具备计算功能的程序，想用WPF和MVVM架构为它做GUI界面。现在的问题是不知道怎么把应用内部变量和View能响应的Model属性关联起来——比如内部变量n变化时，我现在得手动同步更新Model的属性，View才会跟着变。想知道把应用代码整合到MVVM架构里的更优方案是什么？

以下是我简化后的当前代码：

class ApplicationModel : INotifyPropertyChanged
{
    #region Members
    private int number;
    #endregion

    public ApplicationModel()
    {
        new Thread(() => applicationWork(this)).Start();
    }

    private void applicationWork(ApplicationModel appModel)
    {            
        // internal variables
        int n = 0;

        // simulating my app running, changing variables
        while (true)
        { 
            Thread.Sleep(1000);
            n++;
            appModel.number++;
            // how do I tie the two together?            
        }        
    }

    #region Properties
    public int Number
    {
        get
        {
            return number;
        }
        set
        {
            number = value;
            OnPropertyChanged("Number");
        }
    }
    #endregion

    #region INotifyPropertyChanged Members  
    public event PropertyChangedEventHandler? PropertyChanged;
    private void OnPropertyChanged(string propertyName)
    {
        // ...
    }
    #endregion
}

优化方案 #

1. 用Model属性替代内部变量（最直接） #

没必要同时维护n和number两个变量，直接把Model的Number属性作为业务状态的唯一来源，这样变量变化时会自动触发PropertyChanged通知View更新：

class ApplicationModel : INotifyPropertyChanged
{
    #region Members
    private int number;
    #endregion

    public ApplicationModel()
    {
        new Thread(applicationWork).Start();
    }

    private void applicationWork()
    {            
        while (true)
        { 
            Thread.Sleep(1000);
            // 直接通过公共属性修改，自动触发通知
            Number++;
        }        
    }

    #region Properties
    public int Number
    {
        get => number;
        set
        {
            // 避免重复触发不必要的通知
            if (number == value) return;
            number = value;
            // 用nameof替代硬编码字符串，避免拼写错误
            OnPropertyChanged(nameof(Number));
        }
    }
    #endregion

    #region INotifyPropertyChanged Members  
    public event PropertyChangedEventHandler? PropertyChanged;
    private void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
    #endregion
}

2. 封装内部状态，同步更新属性（保留内部变量场景） #

如果业务逻辑必须单独维护内部变量n，可以在内部变量变化时主动更新Model的公共属性，或者在属性setter里反向同步内部状态：

class ApplicationModel : INotifyPropertyChanged
{
    #region Members
    private int number;
    // 业务逻辑需要的内部变量
    private int n;
    #endregion

    public ApplicationModel()
    {
        new Thread(applicationWork).Start();
    }

    private void applicationWork()
    {            
        n = 0;
        while (true)
        { 
            Thread.Sleep(1000);
            n++;
            // 内部变量更新后同步到公共属性
            Number = n;
        }        
    }

    #region Properties
    public int Number
    {
        get => number;
        set
        {
            if (number == value) return;
            number = value;
            OnPropertyChanged(nameof(Number));
            // 可选：如果需要从UI反向同步内部变量
            n = value;
        }
    }
    #endregion

    #region INotifyPropertyChanged Members  
    public event PropertyChangedEventHandler? PropertyChanged;
    private void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
    #endregion
}

3. 标准MVVM分层：业务Model+ViewModel（解耦业务与UI） #

如果需要严格分离业务逻辑和UI逻辑，建议引入ViewModel层——Model只负责业务数据和逻辑，ViewModel作为中间层监听Model变化并同步给View：

// 业务Model：只处理业务逻辑，不实现UI相关的通知接口
class BusinessModel
{
    public int N { get; private set; }

    public void StartWork()
    {
        new Thread(() =>
        {
            N = 0;
            while (true)
            {
                Thread.Sleep(1000);
                N++;
                // 业务状态变化时触发自定义事件
                OnBusinessStateUpdated();
            }
        }).Start();
    }

    public event EventHandler? BusinessStateUpdated;
    private void OnBusinessStateUpdated()
    {
        BusinessStateUpdated?.Invoke(this, EventArgs.Empty);
    }
}

// ViewModel：实现INotifyPropertyChanged，适配UI需求
class MainViewModel : INotifyPropertyChanged
{
    private readonly BusinessModel _businessModel;
    private int _displayNumber;

    public int DisplayNumber
    {
        get => _displayNumber;
        set
        {
            if (_displayNumber == value) return;
            _displayNumber = value;
            OnPropertyChanged(nameof(DisplayNumber));
        }
    }

    public MainViewModel()
    {
        _businessModel = new BusinessModel();
        // 监听业务Model的状态变化
        _businessModel.BusinessStateUpdated += OnBusinessModelUpdated;
        _businessModel.StartWork();
    }

    private void OnBusinessModelUpdated(object? sender, EventArgs e)
    {
        // 必须切换到UI线程更新属性，避免WPF跨线程绑定报错
        Application.Current.Dispatcher.Invoke(() =>
        {
            DisplayNumber = _businessModel.N;
        });
    }

    #region INotifyPropertyChanged Members
    public event PropertyChangedEventHandler? PropertyChanged;
    private void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
    #endregion
}

关键注意点 #

• 跨线程更新属性时，必须通过Dispatcher切换到UI线程，否则WPF会抛出线程异常。
• 尽量保持单一数据源，避免多个变量同步带来的出错概率。
• 标准MVVM架构中，Model不直接和View交互，所有UI相关的逻辑都交给ViewModel处理，这样分层更清晰，代码更易维护。

内容的提问来源于stack exchange，提问作者StefanoN