dllimport failed to locate dll even though it is in the PATH

Question

I use [Dllimport("DllName.dll")] where I'm sure a path to my dll exists in the process PATH environment variable, and still I get "DllName.dll could not be found"

Agace

Please Check Target Platform( X86 or x64 or AnyCPU) – Aesthetics

Answer 1

"DllName.dll could not be found" could also mean that DllImport has not found one of DllName.dll dependencies.

Grab Dependecy Walker to check which dependecy you are missing.

Strobila

Answer 2

I'd suggest you to use FileMon (sysinternals.com) to check if your assumptions about the library location are right.

Flagella

Answer 3

DllImport does not consult the PATH environment variable when loading DLL's. I am fairly certain that DllImport follows the standard rules for loading a native DLL in a native program when the DLL is referenced by name. Here is an article which details those rules

http://msdn.microsoft.com/en-us/library/ms682586.aspx

I've found the simplest way to load the DLL is just to put it in the same location as the program I am executing.

Carpi

Maybe I'm miss understanding your answer but it doesn't sound right. I created a simple asp.net web app that uses the DllImport attribute to call a simple exported function from a custom c++ dll. Without updating the path environment variable I get the "Unable to load DLL" exception. However, when the path environment variable is updated to include the path to dll I can call the external function just fine. – Balthazar

I'm having the same problem here. if i use DllImport("sample.dll"), it wont work. But if I try DllImport("C:\\Somelocation\\sample.dll"), it works. – Timbering

Answer 4

I used const string lcms2Path = "C:\\lcms2.dll"; in my C# application for the longest time. But finally moved the DLL to the BIN folder and this works perfect [DllImport("lcms2.dll")].

Chauvinism