Error C3918: Error wile checking event for being nullptr

Question

I have delegate and event in my .h file

delegate void ResponseReceivedHandler(System::Object^ sender, WhoisEventArgs^ e);
event ResponseReceivedHandler^ ResponseReceived;

somewhere in my code I want to check if event is nullptr or no, but when I write

EDITED:

if (this->ResponseReceived != nullptr)
{
     this->ResponseReceived(this, e);
}

Error occurred

Error 1 error C3918: usage requires 'VT::WhoisClient::WhoisRequest::ResponseReceived' to be a data member c:\Users\ViToBrothers\Desktop\ViTo Projects\VT.WhoisClient\VT.WhoisClient\VT.WhoisRequest.cpp 50

What can I do ?

I get example from the C# and want to change to C++ .NET ... — Viktor Apoyan, May 17 '11 at 17:47
maybe there is no need to write if (this.ResponseReceived != null) this line — Viktor Apoyan, May 17 '11 at 17:48
`this.` doesn't work in C++. `this` is a pointer. pointers are used with `->`. You need to use the correct C++ syntax or you will get compile errors. — Ben Voigt, May 17 '11 at 18:04

score 3 · Accepted Answer · answered May 17 '11 at 17:59

3

I believe that in this case, the compiler is generating the accessor functions and backing storage for the event handler delegate. Thus, it is not necessary for you to check for null.

See more here: http://msdn.microsoft.com/en-us/library/4b612y2s.aspx

answered May 17 '11 at 17:59

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And the documentation [here](http://msdn.microsoft.com/en-us/library/4b612y2s.aspx) explains how to raise events. – Ben Voigt May 17 '11 at 18:03

Error C3918: Error wile checking event for being nullptr

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