Check if application was started from within Visual Studio debug session

Question

I am working on an application that installs a system wide keyboard hook. I do not want to install this hook when I am running a debug build from inside the visual studio (or else it would hang the studio and eventually the system), and I can avoid this by checking if the DEBUG symbol is defined.

However, when I debug the release version of the application, is there a way to detect that it has been started from inside visual studio to avoid the same problem? It is very annoying to have to restart the studio/the computer, just because I had been working on the release build, and want to fix some bugs using the debugger having forgotten to switch back to the debug build.

Currently I use something like this to check for this scenario:

System.Diagnostics.Process currentProcess = System.Diagnostics.Process.GetCurrentProcess();
string moduleName = currentProcess.MainModule.ModuleName;
bool launchedFromStudio = moduleName.Contains(".vshost");

I would call this the "brute force way", which works in my setting, but I would like to know whether there's another (better) way of detecting this scenario.

Note: I got the following strings when trying this technique vstest.executionengine.x86.exe WebDev.WebServer20.exe launching from Visual Studio test and via code running under IIS Express. So anyone reading this may need to adjust code accordingly. — James Westgate, Aug 07 '15 at 09:23
With Visual Studio 2022 I'm using this brute force method and "iisexpress.exe" instead of ".vshost" — DeveloperDan, Sep 14 '22 at 19:31

score 69 · Accepted Answer · edited Oct 05 '18 at 12:23

69

Try: System.Diagnostics.Debugger.IsAttached

edited Oct 05 '18 at 12:23

Contango

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answered Sep 19 '08 at 13:29

TraumaPony

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(Updated Comment) Debugger.IsAttached is adequate and will satisfy many requirements. However it only addresses whether a debugger is attached (any debugger, including WinDbg). If running in the IDE without debugging, it won't always work as advertised. The OP's suggested code is the best way to determine whether the program is running in the IDE. NOTE: CodedUI tests do not use "vshost". Instead they use QTAgent.exe, QTAgent32.exe, and QTAgent64.exe, among others. So use `moduleName.ToLower.Contains("qtagent");`. – Barniferous Sep 30 '16 at 17:43
@Barniferous, looks like starting with VS 2017 checking for ".vshost" no longer works as VS 2017 has stopped adding it to the name. I don't know what CodedUI tests do... – Jim Mar 23 '17 at 17:41

score 19 · Answer 2 · answered Sep 19 '08 at 13:43

19

For those working with Windows API, there's a function which allows you to see if any debugger is present using:

if( IsDebuggerPresent() )
{
    ...
}

Reference: http://msdn.microsoft.com/en-us/library/ms680345.aspx

answered Sep 19 '08 at 13:43

William Casarin

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I used this approach but then saw the blog in the following link where he claims he dissabled IsDebuggerPresent through a script: https://blogs.msdn.microsoft.com/debuggingtoolbox/2007/05/23/windbg-script-disabling-isdebuggerpresent/ – TBD Mar 22 '16 at 06:27

score 5 · Answer 3 · edited Oct 03 '12 at 07:42

Testing whether or not the module name of the current process contains the string ".vshost" is the best way I have found to determine whether or not the application is running from within the VS IDE.

Using the System.Diagnostics.Debugger.IsAttached property is also okay but it does not allow you to distinguish if you are running the EXE through the VS IDE's Run command or if you are running the debug build directly (e.g. using Windows Explorer or a Shortcut) and then attaching to it using the VS IDE.

You see I once encountered a problem with a (COM related) Data Execution Prevention error that required me to run a Post Build Event that would execute editbin.exe with the /NXCOMPAT:NO parameter on the VS generated EXE.

For some reason the EXE was not modified if you just hit F5 and run the program and therefore AccessViolationExceptions would occur on DEP-violating code if run from within the VS IDE - which made it extremely difficult to debug. However, I found that if I run the generated EXE via a short cut and then attached the VS IDE debugger I could then test my code without AccessViolationExceptions occurring.

So now I have created a function which uses the "vshost" method that I can use to warn about, or block, certain code from running if I am just doing my daily programming grind from within the VS IDE.

This prevents those nasty AccessViolationExceptions from being raised and thereby fatally crashing the my application if I inadvertently attempt to run something that I know will cause me grief.

Correct, also don't forget things like remote debugging, other debuggers than Visual Studio, etc. — atlaste, Aug 06 '14 at 19:54
See my comment under the OP's post, you get different module names if you launch a test or IIS express project. — James Westgate, Aug 07 '15 at 09:23
I used to also check for ".vshost", but now it looks like starting with VS 2017 checking for ".vshost" no longer works as VS 2017 has stopped adding it to the name. I stumbled upon this thread looking for a new way of detecting debugging from VS. — Jim, Mar 23 '17 at 17:45

Check if application was started from within Visual Studio debug session

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