可以帮我写一个WPF MVVM命令绑定的实现嘛？

当然可以，下面是一个基本的WPF MVVM命令绑定的实现：

首先，创建一个命令类：

public class RelayCommand : ICommand
{
    private readonly Action<object> _execute;
    private readonly Predicate<object> _canExecute;

    public RelayCommand(Action<object> execute, Predicate<object> canExecute = null)
    {
        _execute = execute ?? throw new ArgumentNullException(nameof(execute));
        _canExecute = canExecute;
    }

    public bool CanExecute(object parameter)
    {
        return _canExecute == null || _canExecute(parameter);
    }

    public void Execute(object parameter)
    {
        _execute(parameter);
    }

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

然后在ViewModel中定义需要绑定的命令：

public class MainViewModel : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    private void OnPropertyChanged(string propertyName)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }

    private RelayCommand _openCommand;

    public RelayCommand OpenCommand
    {
        get
        {
            if (_openCommand == null)
            {
                _openCommand = new RelayCommand(p => Open(), p => CanOpen());
            }
            return _openCommand;
        }
    }

    private bool CanOpen()
    {
        //检查是否可以执行打开命令
        return true;
    }

    private void Open()
    {
        //执行打开命令
    }
}

最后，在View中绑定命令：

<Button Content="打开" Command="{Binding OpenCommand}" />

完成后，当用户单击按钮时，将自动调用ViewModel中的OpenCommand方法，而不需要在View中处理任何逻辑。