将参数传递给ICommand

Question

我有一个简单的按钮,在执行时使用命令,这一切都正常,但我想在单击按钮时传递一个文本参数.

我认为我的XAML没问题,但我不确定如何编辑我的RelayCommand类来接收参数:

<Button x:Name="AddCommand" Content="Add" 
    Command="{Binding AddPhoneCommand}"
    CommandParameter="{Binding Text, ElementName=txtAddPhone}" />

public class RelayCommand : ICommand
{
    private readonly Action _handler;
    private bool _isEnabled;

    public RelayCommand(Action handler)
    {
        _handler = handler;
    }

    public bool IsEnabled
    {
        get { return _isEnabled; }
        set
        {
            if (value != _isEnabled)
            {
                _isEnabled = value;
                if (CanExecuteChanged != null)
                {
                    CanExecuteChanged(this, EventArgs.Empty);
                }
            }
        }
    }

    public bool CanExecute(object parameter)
    {
        return IsEnabled;
    }

    public event EventHandler CanExecuteChanged;

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

Answer 1

改变Action以Action<T>使得它需要一个参数(可能只是Action<object>最容易).

private readonly Action<object> _handler;

然后简单地传递参数:

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

Answer 2

你可以这样做

public ICommand AddPhoneCommand
{
    get
    {
        return new Command<string>((x) =>
        {
            if(x != null) { AddPhone(x); }
        };
    }
}

然后，当然有你的AddPhone：

public void AddPhone(string x)
{
    //handle x
}