.NET assembly created by Matlab NE Builder cannot be used from Matlab ("The type initializer for ... threw an exception")?

Question

Yuri Shirman on 19 Aug 2013

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Direct link to this question

https://ch.mathworks.com/matlabcentral/answers/85042-net-assembly-created-by-matlab-ne-builder-cannot-be-used-from-matlab-the-type-initializer-for

Answered: Dhruvesh Patel on 2 Feb 2017

Open in MATLAB Online

Initial intention (summary):

1. Call a .NET DLL from Matlab and analyze the results.

2. Add some Matlab algorithm to this DLL (i.e. call .NET assembly created from Matlab script by Builder NE)

3. Repeat step 1.

Resulting failure:

The type initializer for Namespace.<Class> threw an exception

Steps for simplified version of the test:

1. Create with deploytool a project Summator.prj (.NET assembly, class SumClass) wrapping a simple script, say:

function img = imagesum(img1, img2)
img = img1 + img2;

2. Build the project: the assemblies Summator.dll and SummatorNative.dll can be found now in C:\Users\MyName\Documents\MATLAB\Test.NET\Summator\distrib .

3. Try to load the assembly from Matlab:

myroot = 'C:\Users\MyName\Documents\MATLAB\Test.NET'
mypath=fullfile(myroot,'\Summator\distrib');
addpath(mypath);
asm = NET.addAssembly(fullfile(mypath,'Summator.dll'));
import Summator.*;
try
    mysummator = Summator.SumClass();
catch ex
    disp(ex); 
    disp(ex.ExceptionObject);
    disp(ex.ExceptionObject.TypeName);
    disp(ex.ExceptionObject.Message);
    disp(ex.ExceptionObject.InnerException);
    disp(ex.ExceptionObject.TargetSite);
    disp(ex.ExceptionObject.StackTrace);
    disp(ex.ExceptionObject.Source);
end

The result:

    myroot =
    C:\Users\MyName\Documents\MATLAB\Test.NET
    NET.NetException
    Package: NET
    Properties:
      ExceptionObject: [1x1 System.TypeInitializationException]
           identifier: 'MATLAB:NET:CLRException:CreateObject'
              message: 'Message: The type initializer for 'Summator.SumClass' threw an exception.
  Source: mscorlib
  HelpLink: '
                cause: {}
                stack: [1x1 struct]
    Methods, Superclasses
    System.TypeInitializationException handle
    Package: System
    Properties:
            TypeName: [1x1 System.String]
             Message: [1x1 System.String]
                Data: [1x1 System.Collections.ListDictionaryInternal]
      InnerException: [1x1 System.TypeInitializationException]
          TargetSite: [1x1 System.Reflection.RuntimeMethodInfo]
          StackTrace: [1x1 System.String]
            HelpLink: []
              Source: [1x1 System.String]
             HResult: -2146233036
    Methods, Events, Superclasses
Summator.SumClass
The type initializer for 'Summator.SumClass' threw an exception.
    System.TypeInitializationException handle
    Package: System
    Properties:
            TypeName: [1x1 System.String]
             Message: [1x1 System.String]
                Data: [1x1 System.Collections.ListDictionaryInternal]
      InnerException: [1x1 System.Exception]
          TargetSite: [1x1 System.Reflection.RuntimeConstructorInfo]
          StackTrace: [1x1 System.String]
            HelpLink: []
              Source: [1x1 System.String]
             HResult: -2146233036
    Methods, Events, Superclasses
    System.Reflection.RuntimeMethodInfo handle
    Package: System.Reflection
    Properties:
                            Name: [1x1 System.String]
                   DeclaringType: [1x1 System.RuntimeType]
                   ReflectedType: [1x1 System.RuntimeType]
                      MemberType: [1x1 System.Reflection.MemberTypes]
                   MetadataToken: 100667905
                          Module: [1x1 System.Reflection.RuntimeModule]
              IsSecurityCritical: 1
          IsSecuritySafeCritical: 1
           IsSecurityTransparent: 0
                    MethodHandle: [1x1 System.RuntimeMethodHandle]
                      Attributes: [1x1 System.Reflection.MethodAttributes]
               CallingConvention: [1x1 System.Reflection.CallingConventions]
                      ReturnType: [1x1 System.RuntimeType]
      ReturnTypeCustomAttributes: [1x1 System.Reflection.RuntimeParameterInfo]
                 ReturnParameter: [1x1 System.Reflection.RuntimeParameterInfo]
                 IsGenericMethod: 0
       IsGenericMethodDefinition: 0
       ContainsGenericParameters: 0
       MethodImplementationFlags: [1x1 System.Reflection.MethodImplAttributes]
                        IsPublic: 0
                       IsPrivate: 0
                        IsFamily: 0
                      IsAssembly: 1
             IsFamilyAndAssembly: 0
              IsFamilyOrAssembly: 0
                        IsStatic: 1
                         IsFinal: 0
                       IsVirtual: 0
                     IsHideBySig: 1
                      IsAbstract: 0
                   IsSpecialName: 0
                   IsConstructor: 0
                CustomAttributes: [1x1 System.Collections.ObjectModel.ReadOnlyCollection<System*Reflection*CustomAttributeData>]
    Methods, Events, Superclasses
     at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
     at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
     at System.Reflection.ConstructorInfo.Invoke(Object[] parameters)
     at dotnetcli.NETConstructor.invoke(NETConstructor* , COSClient* client, Int32* nlhs, COSValue* plhs, Int32 nrhs, COSValue* prhs)
mscorlib

The most important point: If I use the DLL from .NET application everything works, e.g.:

NETApp.ex -> NETAlgo.dll -> Summator.dll = Success

Matlab.exe -> Summator.dll = _Failure _(as shown above)

Matlab.exe -> NETAlgo.dll -> Summator.dll = Failure (same way)

Details (environment) :

A. MATLAB Version: 8.0.0.783 (R2012b) 32-bit

Operating System: Microsoft Windows 7 Version 6.1 (Build 7601: Service Pack 1) Java Version: Java 1.6.0_17-b04 with Sun Microsystems Inc. Java HotSpot™ Client VM mixed mode

B. .NET framework: v4.0.30319