What are the uses of using? The problem with putting using namespace in the header files of your classes is that it forces anyone who wants to use your classes (by including your header files) to also be using (i. e. - do not put a using declaration (or using directive) at file scope in an include file/header! · user kokos answered the wonderful hidden features of c# question by mentioning the using keyword. The identifier following the using … Seeing everything in) … Although i think it would be better to organize like this because its a lot easier to see what is … · in c++11, the using keyword when used for type alias is identical to typedef. // do something what is the difference between using and await using? Can you elaborate on that? I have been running stylecop over some c# code, and it keeps reporting that my using directives should be inside the namespace. · using var disposable = new disposable(); 7. 1. 3. 2 a typedef-name can also be introduced by an alias-declaration. Is there a technical reason for putting the using directives inside · in a mysql join, what is the difference between on and using()? Using calls dispose() after the using -block is left, even if the code throws an exception. Either way, when the using block is exited (either by successful completion or by error) it is closed. How should i decide which one to use? That will cause headaches for users of the header. So you usually use using for classes that require cleaning up after them, like io. · just in case its not clear from the other answers here: As far as i can tell, using() is just more convenient syntax, whereas on allows a little more flexibility when the column … Updating the using keyword was specifically for templates, and (as was pointed out in the accepted answer) when you are working with non-templates using and typedef are mechanically identical, so the …