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How to handle exceptions?

It's a question about best .net 开发者_开发技巧practise. I always caught and stored information about exceptions in all of my web and window forms applications as follows:

  1. Surrounded each method with try catch(Exception exception)
  2. For any layer except front layer, threw exception to the layer above
  3. In the front layer, logged the exception to a log file (usually using log4config.dll) and presented a user friendly message to the user.

Is this the best way to handle exceptions? Or should I do something different in my next projects?


I wouldn't add 1 & 2 unless I had some specific reason; for example to alter (wrap) the message; there is no need since exceptions will raise upwards anyway. And done incorrectly you can accidentally remove the all-important stack-trace (throw; vs throw ex; - the first being preferred).


The following code is problematic because it overwrites the original stack trace for e, which makes problems harder to diagnose:

public void Foo() {
    try {
        Bar();
    } catch(Exception e) {
        throw e; // re-throw; overwrites original stacktrace in 'e'
    }
}

The following code does not have the above stacktrace overwrite problem, but is still unnecessarily verbose:

public void Foo() {
    try {
        Bar();
    } catch(Exception e) {
        throw; // re-throw; preserves original stacktrace in 'e'
    }
}

Both would be better written as below. This is because, if the only thing you are doing in your catch block is re-throwing the exception, there is no need to write the catch block at all:

public void Foo() {
    Bar();
}


The best answer you can get at Best Practices for Handling Exceptions


Here is how NOT to handle exceptions.

public void method1(){
    try{
        ....
        // all the code goes here
        // declare any helper methods throw throwable
        // eg: private boolean check1() throws Throwable{ ...}
        ....   
    }catch(Throwable t){
       System.out.println("oops...error...good luck debugging. ");
    }
}
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