OpenCVSharp: Unable to load DLL 'OpenCvSharpExtern'

user_113718 0
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I have installed the latest OpenCVSharp 2 (2.4.10.201...) with the NuGet manager in my project. Everything concerning OpenCVSharp.CvMat is working OK (loading, manipulation etc) so I am sure the installation is correct.

However I cannot use OpenCVSharp.CPlusPlus at all! The problem is that it doesn't load OpenCvSharpExtern.dll.

Error shown from try-catch block:

try
{
    Mat mat = new Mat();
} catch (Exception err)
{
    Console.WriteLine( err );
}

System.TypeInitializationException: The type initializer for 'OpenCvSharp.CPlusPlus.Mat' threw an exception. ---> System.DllNotFoundException: Unable to load DLL 'OpenCvSharpExtern': The specified module could not be found. (Exception from HRESULT: 0x8007007E)
   at OpenCvSharp.CPlusPlus.NativeMethods.core_Mat_sizeof()
   at OpenCvSharp.CPlusPlus.Mat..cctor()
   --- End of inner exception stack trace ---
   at OpenCvSharp.CPlusPlus.Mat..ctor()
   at MainClass.Main() in C:\Users\kotsias\Documents\Visual Studio 2015\Projects\MyCVSharp\ConsoleApplication1\Test.cs:line 14

The OpenCvSharpExtern.dll IS deployed alongside my .exe inside the following subfolders:

..\dll\x86

&

..\dll\x64

If I manually copy the x64 .dll in the same folder as my .exe, I still get the same error above. If I copy the x86 .dll, I get a different error:

System.TypeInitializationException: The type initializer for 'OpenCvSharp.CPlusPlus.Mat' threw an exception. ---> System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)
   at OpenCvSharp.CPlusPlus.NativeMethods.core_Mat_sizeof()
   at OpenCvSharp.CPlusPlus.Mat..cctor()
   --- End of inner exception stack trace ---
   at OpenCvSharp.CPlusPlus.Mat..ctor()
   at MainClass.Main() in C:\Users\kotsias\Documents\Visual Studio 2015\Projects\MyCVSharp\ConsoleApplication1\Test.cs:line 14
opencv .net c#
4 Answers

It is not enough installing the "OpencvSharp{version} nuget" package. You also have to install the "OpencvSharp{version}.runtime.{operating_system}" package.

For example, in my case I had to install the following Nuget pacages:

  • OpencvSharp4
  • OpencvSharp4.runtime.win
user_29421580

Another issue that some may be hitting:

OpenCvSharpExtern.dll requires mfplat.dll that is part of the Media Feature Pack. Windows 'N' editions do not include this by default.

It can be installed from Apps and Features->Optional features->Add a feature.

user_6605360

Use this code on Package manager :

Install-Package OpenCvSharp4.Windows -Version 4.0.0.20190108
user_36435340
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