c# - 在将对象作为有效负载的 View 模型之间使用Prism 6 Event Aggregator

Question

嗨，我希望你们中的一个可以帮助我一些语法。

所以我在使用Prism Event Aggregator将消息从一个ViewModel发送到另一个ViewModel时遵循了这个示例https://www.codeproject.com/Tips/591221/Simple-EventAggregator-in-WPF-PRISM。

当发布单个字符串作为有效负载时，以下代码非常有用。

internal class OrderSelectedEvent_SS : PubSubEvent<string>
{
    private static readonly EventAggregator _eventAggregator;
    private static readonly OrderSelectedEvent_SS _event;

    static OrderSelectedEvent_SS()
    {
        _eventAggregator = new EventAggregator();
        _event = _eventAggregator.GetEvent<OrderSelectedEvent_SS>();
    }

    public static OrderSelectedEvent_SS Instance
    {
        get { return _event; }
    }
}

发布者(在ViewModel1中):

OrderSelectedEvent_SS.Instance.Publish(_strCurrentOrder);

订阅者(在ViewModel2中:

OrderSelectedEvent_SS.Instance.Subscribe(OrderSelectedEventHandler_SS);
private void OrderSelectedEventHandler_SS(string strSelectedOrder)
    {
        CurrentOrder = strSelectedOrder;
    }

我正在尝试做的是修改以接受对象(具有多个字符串的类)作为有效负载。
这是我到目前为止的内容:

internal class OrderSelectedEvent : PubSubEvent<object>
{
    private static readonly EventAggregator _eventAggregator;
    private static readonly OrderSelectedEvent _event;
    static OrderSelectedEvent()
    {
        _eventAggregator = new EventAggregator();
        _event = _eventAggregator.GetEvent<OrderSelectedEvent>();
    }

    public static OrderSelectedEvent Instance
    {
        get { return _event; }
    }

    public class OrderSelectedPayload
    {
        public string SelectedOrder { get; set; }
        public string SelectedE32 { get; set; }
    }
}

发布者(在ViewModel1中):

OrderSelectedEvent.OrderSelectedPayload ospl = new OrderSelectedEvent.OrderSelectedPayload();
ospl.SelectedOrder = _strCurrentOrder;
ospl.SelectedE32 = _strCurrentE32JobNumber;
OrderSelectedEvent.Instance.Publish(ospl);

订阅者(在ViewModel2中:

OrderSelectedEvent.Instance.Subscribe(OrderSelectedEventHandler); 

我在subsriber上遇到错误:**错误:无法从“方法组”转换为“操作” ****，而且我似乎无法弄清楚我需要做什么。

private void OrderSelectedEventHandler(OrderSelectedEvent.OrderSelectedPayload ospl)
{
    CurrentOrder = ospl.SelectedOrder;
    CurrentE32JobNumber = ospl.SelectedE32;
}

在此先感谢您提供的任何指导。

Answer 1

您的问题很简单:您正在定义事件以将object传递为有效负载，然后尝试使用特定的类作为有效负载。要解决此问题，请更改

internal class OrderSelectedEvent : PubSubEvent<object>

到:

internal class OrderSelectedEvent : PubSubEvent<OrderSelectedPayload>

另外，您可以更改处理程序签名以匹配事件的预期参数:

private void OrderSelectedEventHandler(OrderSelectedEvent.OrderSelectedPayload ospl)

到:

private void OrderSelectedEventHandler(object ospl)