Question

I try to load a assembly into my source code in C#. So i first compile the source file:

 private bool testAssemblies(String sourceName)
        {
            FileInfo sourceFile = new FileInfo(sourceName);
            CodeDomProvider provider = null;
            bool compileOk = false;

            // Select the code provider based on the input file extension.
            if (sourceFile.Extension.ToUpper(CultureInfo.InvariantCulture) == ".CS")
            {
                provider = CodeDomProvider.CreateProvider("CSharp");
            }
            else if (sourceFile.Extension.ToUpper(CultureInfo.InvariantCulture) == ".VB")
            {
                provider = CodeDomProvider.CreateProvider("VisualBasic");
            }
            else
            {
                Console.WriteLine("Source file must have a .cs or .vb extension");
            }

            if (provider != null)
            {

                // Format the executable file name.
                // Build the output assembly path using the current directory
                // and <source>_cs.exe or <source>_vb.exe.

                String exeName = String.Format(@"{0}\{1}.exe",
                    System.Environment.CurrentDirectory,
                    sourceFile.Name.Replace(".", "_"));

                CompilerParameters cp = new CompilerParameters();

                // Generate an executable instead of 
                // a class library.
                cp.GenerateExecutable = true;

                // Specify the assembly file name to generate.
                cp.OutputAssembly = exeName;

                // Save the assembly as a physical file.
                cp.GenerateInMemory = false;

                // Set whether to treat all warnings as errors.
                cp.TreatWarningsAsErrors = false;

                // Invoke compilation of the source file.
                CompilerResults cr = provider.CompileAssemblyFromFile(cp,
                    sourceName);

                if (cr.Errors.Count > 0)
                {
                    // Display compilation errors.
                    Console.WriteLine("Errors building {0} into {1}",
                        sourceName, cr.PathToAssembly);
                    foreach (CompilerError ce in cr.Errors)
                    {
                        Console.WriteLine("  {0}", ce.ToString());
                        Console.WriteLine();
                    }
                }
                else
                {
                    // Display a successful compilation message.
                    Console.WriteLine("Source {0} built into {1} successfully.",
                        sourceName, cr.PathToAssembly);
                }

                // Return the results of the compilation.
                if (cr.Errors.Count > 0)
                {
                    compileOk = false;
                }
                else
                {
                    compileOk = true;
                }
            }
            return compileOk;
        }

This works well, but if I later try to load the assembly, I always get an exception:

System.Reflection.TargetInvocationException was unhandled
  Message=Exception has been thrown by the target of an invocation.
  Source=mscorlib
  StackTrace:
       at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
       at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
       at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
       at System.Delegate.DynamicInvokeImpl(Object[] args)
       at Microsoft.Surface.Shell.ApiEventManager.EventSubscriberInfo.InvokeCallback(Object arg)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
       at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
       at System.Windows.Threading.DispatcherOperation.InvokeImpl()
       at System.Windows.Threading.DispatcherOperation.InvokeInSecurityContext(Object state)
       at System.Threading.ExecutionContext.runTryCode(Object userData)
       at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Windows.Threading.DispatcherOperation.Invoke()
       at System.Windows.Threading.Dispatcher.ProcessQueue()
       at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Boolean isSingleParameter)
       at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.WrappedInvoke(Delegate callback, Object args, Boolean isSingleParameter, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.InvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Boolean isSingleParameter)
       at System.Windows.Threading.Dispatcher.Invoke(DispatcherPriority priority, Delegate method, Object arg)
       at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
       at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
       at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
       at System.Windows.Threading.Dispatcher.Run()
       at System.Windows.Application.RunDispatcher(Object ignore)
       at System.Windows.Application.RunInternal(Window window)
       at System.Windows.Application.Run(Window window)
       at System.Windows.Application.Run()
       at Prototype_Ver1.App.Main() in C:\Users\Roflcoptr\Documents\Visual Studio 2008\Projects\Prototype_Ver1\Prototype_Ver1\obj\Debug\App.g.cs:line 0
       at System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: System.IO.FileLoadException
       Message=Could not load file or assembly 'C:\\Users\\Roflcoptr\\Desktop\\hello.cs' or one of its dependencies. The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047)
       Source=mscorlib
       FileName=C:\\Users\\Roflcoptr\\Desktop\\hello.cs
       FusionLog=""
       StackTrace:
            at System.Reflection.AssemblyName.nInit(Assembly& assembly, Boolean forIntrospection, Boolean raiseResolveEvent)
            at System.Reflection.Assembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection)
            at System.Reflection.Assembly.Load(String assemblyString)
            at Prototype_Ver1.SurfaceWindow1.OnApplicationActivated(Object sender, EventArgs e) in C:\Users\Roflcoptr\Documents\Visual Studio 2008\Projects\Prototype_Ver1\Prototype_Ver1\MainWindow.xaml.cs:line 91
       InnerException: 

My loading Method looks like this:

if (testAssemblies("C:\\Users\\Roflcoptr\\Desktop\\hello.cs"))
            {
                Assembly a = Assembly.Load("C:\\Users\\Roflcoptr\\Documents\\Visual Studio 2008\\Projects\\Prototype_Ver1\\Prototype_Ver1\\bin\\Debug\\hello_cs.exe");
            }

Any ideas why it doesnt work?

Answer 1

I think your syntax is wrong. Assembly.load(string) expects the assembly name

Assembly.Load("SampleAssembly, Version=1.0.2004.0, Culture=neutral, PublicKeyToken=8744b20f8da049e3");

Also make sure you’re using the right overload for your needs (which usually is indeed Assembly.Load)
Link

EDIT use this:

AssemblyName an = AssemblyName.GetAssemblyName(filePath);
Assembly.Load(an);