Question

此代码：

// NOTE: IQuote DOES NOT inherit from EventArgs
public interface IQuote// : EventArgs
{
}

class C
{
   //NOTE, this is NOT public event EventHandler<IQuote> QuoteChangeEvent;
    public delegate void QuoteChangeEvent(IQuote q);
}

var c = new C();

c.OnQuoteChange += ProcessQuoteChange;


public static void ProcessQuoteChange(IQuote q)
{
}

工作正常。现在，我要使用Rx。这不起作用，即甚至无法编译：

var priceChangedObservable = Observable.FromEvent<QuoteChangeEvent, QuoteChangeEvent>(
    (handler) =>
    {
        QuoteChangeEvent quoteHandler = (e) => handler(e);                   
    },
    eh => c.OnQuoteChange += eh,
    eh => c.OnQuoteChange -= eh
    );

在线(handler) =>

- "Severity Code    Description Project File    Line    Suppression State   
   Error    CS1643  Not all code paths return a value in lambda expression  
   of type 'Func<Action<QuoteChangeEvent>,   
   QuoteChangeEvent>'       294 Active"

在handler(e)

错误CS1503参数1：无法从“ IQuote”转换为 'QuoteChangeEvent'296有效

从IObservable创建delegate的正确方法是什么？

Answer 1

使用Observable.FromEvent<TDelegate, TEventArgs>时，您应该通过<QuoteChangeEvent, IQuote>：

var priceChangedObservable = Observable.FromEvent<QuoteChangeEvent, IQuote>(
    handler =>
    {
        QuoteChangeEvent quoteHandler = (e) => { handler(e); }; 
        return quoteHandler;         
    },
    eh => c.OnQuoteChange += eh,
    eh => c.OnQuoteChange -= eh
);

如何从委托创建IObservable？

1 个答案: