WPF按钮绑定动态变更命令问题：初始化后命令未更新

你的代码存在几个关键问题导致MyCommand无法随commandStorage更新：

1. 低级语法错误 #

• 类定义缺少继承符号，且接口名拼写错误：public class MyViewModel INotifyPropertChanged 应改为 public class MyViewModel : INotifyPropertyChanged
• 属性setter里是比较操作而非赋值：_commandStorage == value 应改为 _commandStorage = value
• OnPropertyChanged 传入的属性名大小写不匹配：属性名是commandStorage（小写开头），但你传了nameof(CommandStorage)，应该改为nameof(commandStorage)

2. MyCommand的变更未通知UI #

MyCommand是只读计算属性，当commandStorage变化时，UI无法感知MyCommand的取值已改变，因为你没有为MyCommand触发PropertyChanged事件。

修复后的完整ViewModel代码 #

public class MyViewModel : INotifyPropertyChanged
{
    private CommandStorage? _commandStorage;
    public CommandStorage? commandStorage
    {
        get => _commandStorage;
        set
        {
            _commandStorage = value; // 修复赋值错误
            OnPropertyChanged(nameof(commandStorage)); // 修复属性名大小写
            OnPropertyChanged(nameof(MyCommand)); // 新增：通知UI MyCommand已变更
        }
    }

    public ICommand? MyCommand => commandStorage?.MyStoredCommand;

    public event PropertyChangedEventHandler? PropertyChanged;
    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

额外优化建议 #

• 遵循C#属性命名规范（PascalCase），调整属性名称保持风格一致：

  private CommandStorage? _commandStorage;
  public CommandStorage? CommandStorage
  {
      get => _commandStorage;
      set
      {
          _commandStorage = value;
          OnPropertyChanged(nameof(CommandStorage));
          OnPropertyChanged(nameof(MyCommand));
      }
  }
  public ICommand? MyCommand => CommandStorage?.MyStoredCommand;
  

• 补全XAML绑定的闭合标签：

  <Button Command="{Binding MyCommand}" />
  

内容的提问来源于stack exchange，提问作者sausage_mouse