Questions about .net Exceptions

re: Questions about .net Exceptions

Jesper — Thu, 03 Apr 2008 12:02:56 GMT

This seems pretty clear - but I think it is best practice (or at least Code Analysis and FxCop says so) not to catch the general Exception but you should catch a specific exception - like NullReferenceException.

How can you handle this? Do we have to predict every exception which can occur in the code?

re: Questions about .net Exceptions

Tess — Thu, 03 Apr 2008 12:24:47 GMT

the short answer is yes, as a developer you should probably anticipate what exceptions that can occurr in your code if you want it to run correctly. MSDN help shows what exceptions can occurr in different methods.

It may not always be feasible to know all types of exceptions that occurr in which case you could have multiple handlers, one more specific first and then end off with a more generic one. But in reality the generic one should only be for exceptions that you really cant predict.

re: Questions about .net Exceptions

baal — Sat, 05 Apr 2008 14:21:26 GMT

I got an Exception like below:

Exception information:

Exception type: HttpRequestValidationException

Exception message: A potentially dangerous Request.Form value was detected from the client (CompanyIntroduce="...a you buy <a href= http://buys...").

How I can deal this Exception in try/catch? because this happen when post data(with html tags) to another page. I don't want to redirect to the custom errors page or show the exception/stack on the page

re: Questions about .net Exceptions

Tess — Mon, 07 Apr 2008 11:02:08 GMT

Baal, if you yourself is sending script tags then you have to remove the validation, but i would avoid sending script tags in the first place.

To handle it you would have to handle it something like this...

http://www.romsteady.net/blog/2007/06/how-to-catch-httprequestvalidationexcep.html

re: Questions about .net Exceptions

baal — Mon, 07 Apr 2008 12:16:02 GMT

This is not I want. "Rom's Rants" blog is the same way as ustom errors page.

in the

try{

UserName1 = Request.Cookies["UserName1"].Value;

UserName2 = Request.Cookies["UserName2"].Value;

}

catch

{

}

if line of UserName2 has exception, the UserName1 value I still have.

what I want is : post data from a page to b page, some data is saved(soted in local var),when HttpRequestValidationException happen, lost data after it.

so, this is why I want use try/catch

re: Questions about .net Exceptions

baal — Mon, 07 Apr 2008 12:22:08 GMT

do you have any method to do like that?

re: Questions about .net Exceptions

Daniel — Sat, 17 Jan 2009 16:05:52 GMT

I have a quick question.

If an app has started a thread that for some reason throws an exception shouldn't the Application_error in Global.Asax, or HttpApplication.Error catch this?

I would think so, but that appears not necesarrily to be the case.

This is a problem because exceptions from a non-request thread will apparently propagate to w3wp and recycle the application pool.

re: Questions about .net Exceptions

Tess — Sun, 18 Jan 2009 00:39:36 GMT

the application_error will only catch it if it is happens on a request. If you start your own thread you are correct in that it will crash if you throw an exception and don't handle it, so if you create your own threads you need to make sure to set up try/catch blocks if there is a chance that it will throw an exception.

.NET Exceptions: Quick WinDbg/SOS tip on how to dump all the .NET exceptions on the heap

If broken it is, fix it you should — Thu, 16 Apr 2009 14:12:08 GMT

Since a .net exception is a .NET object like any other, it gets stored on the GC heap when you (or some