Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
When you call a delegate object’s BeginInvoke, the system creates an object of type AsyncResult, but BeginInvoke returns a reference of type IAsyncResult interface ( which points to AsyncResult instance) . Why doesn’t BeginInvoke instead return a reference of type AsyncResult?
thanx
This is standard interface based programming.
By returning an IAsyncResult, the framework is free to change the internal implementation at a later time, without breaking code written against the framework’s API. This, in essence, telling us, as developers, that we should not care what type of implementation is used, provided the interface (IAsyncResult) is met.
If, instead, the actual AsyncResult class was returned, then changing to a different class would break existing code.
Also, this allows the framework to use the same interface (IAsyncResult) in multiple places, whether or not the AsyncResult class is appropriate. I’ve taken advantage of this, personally, as I’ve made my own asynchronous functions which return IAsyncResult backed by a different class, which stored the information which was important to me. This allows my own code to work like the framework, without restricting me to the framework’s implementation.