c# - WPF Multibinding - 需要使用 Relay 命令

Question

所以，我有一个元素，它有一个带有 2 个参数的命令要传递。

我以前用我找到的一段代码做到了这一点，但我一生都无法记住如何做或再次找到它。

所以，这是我之前创建的多值转换器:

public class MultiValueConverter : IMultiValueConverter
{

    public object Convert(object[] values, Type targetType,
    object parameter, CultureInfo culture)
    {
        return values.Clone();
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        return (value as string).Split(' ');
    }

}

现在，我只需要在 ICommand 中分配我想要调用的函数。我通常使用类似于以下的行:

enemyPopupTooltip = new RelayCommand(param => this.EnemyPopupTooltipEx(param),null);

但是，当它的多值时，这将不起作用。如何使用我的中继命令通过多值转换器将 2 个参数传递到我的函数中？

作为引用，这是 relaycommand 类中的所有内容:

public class RelayCommand : ICommand
{
    /// <summary>
    /// Initializes a new instance of the <see cref="RelayCommand"/> class.
    /// </summary>
    /// <param name="execute">The execute.</param>
    public RelayCommand(Action<object> execute)
        : this(execute, null)
    {
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="RelayCommand"/> class.
    /// </summary>
    /// <param name="execute">The execute.</param>
    /// <param name="canExecute">The can execute.</param>
    public RelayCommand(Action<object> execute, Predicate<object> canExecute)
    {
        if (execute == null)
            throw new ArgumentNullException("execute");
        _execute = execute;
        _canExecute = canExecute;
    }

    /// <summary>
    /// Defines the method that determines whether the command can execute in its current state.
    /// </summary>
    /// <param name="parameter">Data used by the command.  If the command does not require data to be passed, this object can be set to null.</param>
    /// <returns>
    /// true if this command can be executed; otherwise, false.
    /// </returns>
    public bool CanExecute(object parameter)
    {
        return _canExecute == null ? true : _canExecute(parameter);
    }

    /// <summary>
    /// Occurs when changes occur that affect whether or not the command should execute.
    /// </summary>
    public event EventHandler CanExecuteChanged
    {
        add { CommandManager.RequerySuggested += value; }
        remove { CommandManager.RequerySuggested -= value; }
    }

    /// <summary>
    /// Defines the method to be called when the command is invoked.
    /// </summary>
    /// <param name="parameter">Data used by the command.  If the command does not require data to be passed, this object can be set to null.</param>
    public void Execute(object parameter)
    {
        _execute(parameter);
    }

    /// <summary>
    /// Action
    /// </summary>
    private readonly Action<object> _execute;


    /// <summary>
    /// Predicate
    /// </summary>
    private readonly Predicate<object> _canExecute;

Answer 1

你说:

However, this wont work when its multivalue

这个假设是错误的。它确实有效!

当您的多转换器返回值数组时，该数组将作为参数传递给 Command.Execute 方法。

new RelayCommand(EnemyPopupTooltipEx, null);

public void EnemyPopupTooltipEx(object parameter){
   var values = (object[])parameters;
}

然而，这是非常肮脏的做法。我猜你正在将一些 UIElement(s) 传递给命令参数。这违反了 viewmodel 的责任。考虑将需要引用 UIElement 的代码移动到代码隐藏。