问题描述
我有一个签名为"void Method(string)"的第三方代表.问题是我希望/需要将额外的附加信息传递给MySubscribedMethod(为简单起见，请说MyIntArg).我在订阅时就知道这些信息，但是显然我不允许更改MySubscribedMethod参数列表.
I have a 3rd party delegate with a "void Method (string)" signature.The problem is I want/need to pass extra additional information to MySubscribedMethod (Lets say MyIntArg for simplicity). I know this information at the time of the subscription, but I obviously not allowed to alter the MySubscribedMethod parameter list.
ThirdPartyClass.ThirdPartyDelagate += MySubscribedMethod; // Want to provide MyIntArg
public void MySubscribedMethod(string Arg) {} // Would like to receive MyIntArg
有人知道解决此类问题的方法吗?
Does anyone know an elegant work around for this type of issue?
推荐答案
这是为闭包设计的:
int myIntArg = whatever;
ThirdPartyClass.ThirdPartyDelagate += s => MySubscribedMethod(s, myIntArg);
public void MySubscribedMethod(string Arg, int intArg) {}
C#编译器将为您神奇地创建所有必要的基础结构，以确保在调用ThirdPartyDelegate时将myIntArg传递到MySubscribedMethod
The C# compiler will magically create all the necessary infrastructure for you to ensure that myIntArg is passed into MySubscribedMethod when ThirdPartyDelegate is invoked
(请注意，传递确切值的方式有很多细微差别，只有在您循环使用此值或在分配委托后更改myIntArg才真正重要；请参阅此(如果您对血腥细节感兴趣)
(note there are various subtlies around what exact value gets passed in that only really matter if you're using this in a loop or changing myIntArg after you've assigned the delegate; see this if you're interested in the gory details)
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