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Getting InvalidCastException with a Plugin architecture

I have a plugin architecutre which is using a Shared DLL to implement a plugin interface and a base plugin class (eg. IPlugin & BasePlugin). The shared DLL is used by both the Plugin and the main application.
For some reason, when I try to cast an object that was instantiated by the main application to the shared plugin interface (IPlugin), I get an InvalidCastException saying I cannot cast this interface.
This is despite:
The class definitely implementing the plugin interface.
The Visual Studio debugger saying that "(objInstance is IPlugin)" is true when I mouse-over the statement, despite the same 'if' condition evaluating as false when I step-through the code or run the .exe.
The Visual Studio Immediate Window also confirms that the above condition is true and that is it possible to cast the object successfully.
I have cleaned/deleted all bin folders and also tried both VS2019 and VS2022 with exactly the same outcome.
I am going a little crazy here because I assume it is something to do with perhaps with multiple references of the same DLL somehow causing the issue (like this issue). The fact that the debugger tells me everything is okay makes it hard to trouble-shoot. I'm not sure if it's relevant but I have provided example code and the file structure below:
Shared.dll code
public interface IPlugin
{
}
public class BasePlugin : IPlugin
{
}
Plugin.dll code
class MyPlugin : BasePlugin
{
void Init()
{
// The plugin contains references to the main app dlls as it requires
// to call various functions inside the main app such as adding menu items etc
}
}
Main.exe
(Note: This is pseudo-code only and does not show the plugin framework used to load the plugin DLLs via Assembly.Load())
var obj = Activator.CreateInstance(pluginType); // Plugin type will be 'MyPlugin'
if (obj is IPlugin) // <== This executes as false when executed but evaluates to true in the Visual Studio debugger
{
}
var castObj = (IPlugin)obj // <== This will cause an invalid cast exception
Folder structure
|--- MainApp.exe
|--- Shared.dll
|--- Addins
|------- Plugin.dll
|------- Shared.dll
Does anyone know the reasons how I can trouble-shoot this issue and what might be causing it?

My suggestion is that (using the Properties\Signing tab) you sign your shared dll assembly with a Strong Name Key. If your plugin classes reference a signed copy of the dll, there should be no possibility of confusion.
The application has no prior knowledge of what the plugins are going to be, but it does know that it's going to support IPlugin. Therefore, I would reference the PlugInSDK project directly in the app project.
Testbench
Here's what works for me and maybe by comparing notes we can get to the bottom of it.
static void Main(string[] args)
{
Confirm that the shared dll (known here as PlugInSDK.dll) has already been loaded and display the source location. In the Console output, note the that PublicKeyToken is not null for the SDK assembly (this is due to the snk signing).
var sdk =
AppDomain.CurrentDomain.GetAssemblies()
.Single(asm=>(Path.GetFileName(asm.Location) == "PlugInSDK.dll"));
Console.WriteLine(
$"'{sdk.FullName}'\nAlready loaded from:\n{sdk.Location}\n");
The AssemblyLoad event provides the means to examine on-demand loads as they occur:
AppDomain.CurrentDomain.AssemblyLoad += (sender, e) =>
{
var name = e.LoadedAssembly.FullName;
if (name.Split(",").First().Contains("PlugIn"))
{
Console.WriteLine(
$"{name}\nLoaded on-demand from:\n{e.LoadedAssembly.Location}\n");
}
};
It doesn't matter where the plugins are located, but when you go to discover them I suggest SearchOption.AllDirectories because they often end up in subs like netcoreapp3.1.
var pluginPath =
Path.Combine(
Path.GetDirectoryName(Assembly.GetEntryAssembly().Location),
"..",
"..",
"..",
"PlugIns"
);
Chances are good that a copy of PlugInSDK.dll is going to sneak into this directory. Make sure that the discovery process doesn't accidentally pick this up. Any other Type that implements IPlugin gets instantiated and put in the list.
List<IPlugin> plugins = new List<IPlugin>();
foreach (
var plugin in
Directory.GetFiles(pluginPath, "*.dll", SearchOption.AllDirectories))
{
// Exclude copy of the SDK that gets put here when plugins are built.
if(Path.GetFileName(plugin) == "PlugInSDK.dll") continue;
// Be sure to use 'LoadFrom' not 'Load'
var asm = Assembly.LoadFrom(plugin);
// Check to make sure that any given *.dll
// implements IPlugin before adding to list.
Type plugInType =
asm.ExportedTypes
.Where(type =>
type.GetTypeInfo().ImplementedInterfaces
.Any(intfc => intfc.Name == "IPlugin")
).SingleOrDefault();
if ((plugInType != null) && plugInType.IsClass)
{
plugins.Add((IPlugin)Activator.CreateInstance(plugInType));
}
}
Now just display the result of the plugin discovery.
Console.WriteLine("LIST OF PLUGINS");
Console.WriteLine(
string.Join(
Environment.NewLine,
plugins.Select(plugin => plugin.Name)));
Console.ReadKey();
}
Is this something you're able to repro on your side?

CefSharp NuGet package, AnyCPU cannot find files

I am currently trying to write a small service, which uses CefSharp (v57.0.0) to render HTML to a PDF file and followed the instructions to use "Any CPU" in my project (Feature Request - Add AnyCPU Support).
In my project I used the following assembly resolver that seems to work fine (it loads CefSharp.Core.dll, CefSharp.dll during initialisation):
// Will attempt to load missing assembly from either x86 or x64 subdir
private static Assembly Resolver(object sender, ResolveEventArgs args)
{
if (args.Name.StartsWith("CefSharp", StringComparison.Ordinal))
{
string assemblyName = args.Name.Split(new[] { ',' }, 2)[0] + ".dll";
string archSpecificPath = Path.Combine(
AppDomain.CurrentDomain.SetupInformation.ApplicationBase,
Environment.Is64BitProcess ? "x64" : "x86",
assemblyName);
var outputAssembly = File.Exists(archSpecificPath) ? Assembly.LoadFile(archSpecificPath) : null;
return outputAssembly;
}
return null;
}
For the initialisation of CefSharp I set exactly the same values like in the example:
var settings = new CefSettings()
{
// By default CefSharp will use an in-memory cache, you need to specify a Cache Folder to persist data
CachePath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "CefSharp\\Cache")
};
// Perform dependency check to make sure all relevant resources are in our output directory.
Cef.Initialize(settings, performDependencyCheck: true, browserProcessHandler: null);
However, if I start my simple test, I get the following error code:
Message: System.Exception : Unable to locate required Cef/CefSharp dependencies:
Missing:CefSharp.BrowserSubprocess.exe
Missing:CefSharp.BrowserSubprocess.Core.dll
Missing:CefSharp.Core.dll
Missing:CefSharp.dll
Missing:icudtl.dat
Missing:libcef.dll
Executing Assembly Path:D:\projects\CefService\bin\Debug\x86
Any ideas what might be happening here and how to solve the problem?

The message is pretty clear, other assemblies could not be loaded.
Here are some generic instructions on how to do that:
load native ones (e.g. libcef.dll) first with LoadLibrary and FreeLibrary
see if loading a managed one will automatically load other managed ones it depends, else handle them (tedious)
You might be interested in these tools for spotting dependencies:
http://www.dependencywalker.com/
https://github.com/isindicic/DependencyWalker.Net
How do I determine the dependencies of a .NET application?

Cake (C# make) use .Net Framework methods in build.cake

Maybe a dump question. Cake states that its a build automation system that can be written in C#. I'm actually playing around a bit and now want to know if it is possible to call .Net methods in build.cake. At the time I've the following build.cake:
var target = Argument("target", "Default");
Task("NuGet")
.Does(() =>
{
// Get local directory
// Get all packages.config files in local directory
// Call nuget restore for every file
var currentDir = System.IO.GetCurrentDirectory(); // This doesn't work
var allPgkConfigs = System.IO.Directory.GetFiles(currentDir, "packages.config", System.IO.SearchOption.AllDirectories); // This doesn't work
foreach (var pgk in allPgkConfigs)
{
// GetNuGetPackageId(pkg);
}
});
Task("Build")
.Does(() =>
{
MSBuild("MySolution.sln");
});
RunTarget(target);
When calling build.ps1 -target nuget I get the following error:
PS C:\> .\build.ps1 -Target nuget
Preparing to run build script...
Running build script...
Analyzing build script...
Processing build script...
Compiling build script...
Error: C:/Users/Mewald-T550/XAP_Playground/build.cake(6,26): error CS0234: The type or namespace name 'GetCurrentDirectory' does not exist in the namespace 'System.IO' (are you missing an assembly reference?)
As cake already states it can't find System.IO how can I add this reference to cake?
I know that cake offers some build-in file operations, but I want to know how to add .Net Framework methods to the cake script.
Thx

You're calling a method on a namespace
Change
System.IO.GetCurrentDirectory()
to
System.IO.Directory.GetCurrentDirectory()
Tried this script and it worked just fine
var directory = System.IO.Directory.GetCurrentDirectory();
Information(directory);
That said, Cake has several IO abstractions built in
I.e. this will achieve the same:
var allPgkConfigs = GetFiles("./**/packages.config");
foreach (var pgk in allPgkConfigs)
{
// GetNuGetPackageId(pkg);
}
If you just want the current directory you can use
Context.Environment.WorkingDirectory
or just
var curDir = MakeAbsolute(Directory("./"));
Information("Current directory is: {0}", curDir);

You can use a reference directive:
#r "bin/myassembly.dll"
or
#reference "bin/myassembly.dll"
See http://cakebuild.net/docs/fundamentals/preprocessor-directives

Reference directive
The reference directive is used to reference external assemblies for use in your scripts.
Usage
The directive has one parameter which is the path to the dll to load.
#r "bin/myassembly.dll"
or
#reference "bin/myassembly.dll"
Try make it point to C:\Windows\Microsoft.NET\Framework\v4.0.30319\System.IO.dll

Creating one exe file out of visual studio project with external DLL files [duplicate]

Is it possible to embed a pre-existing DLL into a compiled C# executable (so that you only have one file to distribute)? If it is possible, how would one go about doing it?
Normally, I'm cool with just leaving the DLLs outside and having the setup program handle everything, but there have been a couple of people at work who have asked me this and I honestly don't know.

I highly recommend to use Costura.Fody - by far the best and easiest way to embed resources in your assembly. It's available as NuGet package.
Install-Package Costura.Fody
After adding it to the project, it will automatically embed all references that are copied to the output directory into your main assembly. You might want to clean the embedded files by adding a target to your project:
Install-CleanReferencesTarget
You'll also be able to specify whether to include the pdb's, exclude certain assemblies, or extracting the assemblies on the fly. As far as I know, also unmanaged assemblies are supported.
Update
Currently, some people are trying to add support for DNX.
Update 2
For the lastest Fody version, you will need to have MSBuild 16 (so Visual Studio 2019). Fody version 4.2.1 will do MSBuild 15. (reference: Fody is only supported on MSBuild 16 and above. Current version: 15)

Just right-click your project in Visual Studio, choose Project Properties -> Resources -> Add Resource -> Add Existing File…
And include the code below to your App.xaml.cs or equivalent.
public App()
{
AppDomain.CurrentDomain.AssemblyResolve +=new ResolveEventHandler(CurrentDomain_AssemblyResolve);
}
System.Reflection.Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
{
string dllName = args.Name.Contains(',') ? args.Name.Substring(0, args.Name.IndexOf(',')) : args.Name.Replace(".dll","");
dllName = dllName.Replace(".", "_");
if (dllName.EndsWith("_resources")) return null;
System.Resources.ResourceManager rm = new System.Resources.ResourceManager(GetType().Namespace + ".Properties.Resources", System.Reflection.Assembly.GetExecutingAssembly());
byte[] bytes = (byte[])rm.GetObject(dllName);
return System.Reflection.Assembly.Load(bytes);
}
Here's my original blog post:
http://codeblog.larsholm.net/2011/06/embed-dlls-easily-in-a-net-assembly/

If they're actually managed assemblies, you can use ILMerge. For native DLLs, you'll have a bit more work to do.
See also: How can a C++ windows dll be merged into a C# application exe?

Yes, it is possible to merge .NET executables with libraries. There are multiple tools available to get the job done:
ILMerge is a utility that can be used to merge multiple .NET assemblies into a single assembly.
Mono mkbundle, packages an exe and all assemblies with libmono into a single binary package.
IL-Repack is a FLOSS alterantive to ILMerge, with some additional features.
In addition this can be combined with the Mono Linker, which does remove unused code and therefor makes the resulting assembly smaller.
Another possibility is to use .NETZ, which does not only allow compressing of an assembly, but also can pack the dlls straight into the exe. The difference to the above mentioned solutions is that .NETZ does not merge them, they stay separate assemblies but are packed into one package.
.NETZ is a open source tool that compresses and packs the Microsoft .NET Framework executable (EXE, DLL) files in order to make them smaller.

ILMerge can combine assemblies to one single assembly provided the assembly has only managed code. You can use the commandline app, or add reference to the exe and programmatically merge. For a GUI version there is Eazfuscator, and also .Netz both of which are free. Paid apps include BoxedApp and SmartAssembly.
If you have to merge assemblies with unmanaged code, I would suggest SmartAssembly. I never had hiccups with SmartAssembly but with all others. Here, it can embed the required dependencies as resources to your main exe.
You can do all this manually not needing to worry if assembly is managed or in mixed mode by embedding dll to your resources and then relying on AppDomain's Assembly ResolveHandler. This is a one stop solution by adopting the worst case, ie assemblies with unmanaged code.
static void Main()
{
AppDomain.CurrentDomain.AssemblyResolve += (sender, args) =>
{
string assemblyName = new AssemblyName(args.Name).Name;
if (assemblyName.EndsWith(".resources"))
return null;
string dllName = assemblyName + ".dll";
string dllFullPath = Path.Combine(GetMyApplicationSpecificPath(), dllName);
using (Stream s = Assembly.GetEntryAssembly().GetManifestResourceStream(typeof(Program).Namespace + ".Resources." + dllName))
{
byte[] data = new byte[stream.Length];
s.Read(data, 0, data.Length);
//or just byte[] data = new BinaryReader(s).ReadBytes((int)s.Length);
File.WriteAllBytes(dllFullPath, data);
}
return Assembly.LoadFrom(dllFullPath);
};
}
The key here is to write the bytes to a file and load from its location. To avoid chicken and egg problem, you have to ensure you declare the handler before accessing assembly and that you do not access the assembly members (or instantiate anything that has to deal with the assembly) inside the loading (assembly resolving) part. Also take care to ensure GetMyApplicationSpecificPath() is not any temp directory since temp files could be attempted to get erased by other programs or by yourself (not that it will get deleted while your program is accessing the dll, but at least its a nuisance. AppData is good location). Also note that you have to write the bytes each time, you cant load from location just 'cos the dll already resides there.
For managed dlls, you need not write bytes, but directly load from the location of the dll, or just read the bytes and load the assembly from memory. Like this or so:
using (Stream s = Assembly.GetEntryAssembly().GetManifestResourceStream(typeof(Program).Namespace + ".Resources." + dllName))
{
byte[] data = new byte[stream.Length];
s.Read(data, 0, data.Length);
return Assembly.Load(data);
}
//or just
return Assembly.LoadFrom(dllFullPath); //if location is known.
If the assembly is fully unmanaged, you can see this link or this as to how to load such dlls.

.NET Core 3.0 natively supports compiling to a single .exe
The feature is enabled by the usage of the following property in your project file (.csproj):
<PropertyGroup>
<PublishSingleFile>true</PublishSingleFile>
</PropertyGroup>
This is done without any external tool.
See my answer for this question for further details.

The excerpt by Jeffrey Richter is very good. In short, add the libraries as embedded resources and add a callback before anything else. Here is a version of the code (found in the comments of his page) that I put at the start of Main method for a console app (just make sure that any calls that use the libraries are in a different method to Main).
AppDomain.CurrentDomain.AssemblyResolve += (sender, bargs) =>
{
String dllName = new AssemblyName(bargs.Name).Name + ".dll";
var assem = Assembly.GetExecutingAssembly();
String resourceName = assem.GetManifestResourceNames().FirstOrDefault(rn => rn.EndsWith(dllName));
if (resourceName == null) return null; // Not found, maybe another handler will find it
using (var stream = assem.GetManifestResourceStream(resourceName))
{
Byte[] assemblyData = new Byte[stream.Length];
stream.Read(assemblyData, 0, assemblyData.Length);
return Assembly.Load(assemblyData);
}
};

To expand on #Bobby's asnwer above. You can edit your .csproj to use IL-Repack to automatically package all files into a single assembly when you build.
Install the nuget ILRepack.MSBuild.Task package with Install-Package ILRepack.MSBuild.Task
Edit the AfterBuild section of your .csproj
Here is a simple sample that merges ExampleAssemblyToMerge.dll into your project output.
<!-- ILRepack -->
<Target Name="AfterBuild" Condition="'$(Configuration)' == 'Release'">
<ItemGroup>
<InputAssemblies Include="$(OutputPath)\$(AssemblyName).exe" />
<InputAssemblies Include="$(OutputPath)\ExampleAssemblyToMerge.dll" />
</ItemGroup>
<ILRepack
Parallel="true"
Internalize="true"
InputAssemblies="#(InputAssemblies)"
TargetKind="Exe"
OutputFile="$(OutputPath)\$(AssemblyName).exe"
/>
</Target>

The following method DO NOT use external tools and AUTOMATICALLY include all needed DLL (no manual action required, everything done at compilation)
I read a lot of answer here saying to use ILMerge, ILRepack or Jeffrey Ritcher method but none of that worked with WPF applications nor was easy to use.
When you have a lot of DLL it can be hard to manually include the one you need in your exe. The best method i found was explained by Wegged here on StackOverflow
Copy pasted his answer here for clarity (all credit to Wegged)
1) Add this to your .csproj file:
<Target Name="AfterResolveReferences">
<ItemGroup>
<EmbeddedResource Include="#(ReferenceCopyLocalPaths)" Condition="'%(ReferenceCopyLocalPaths.Extension)' == '.dll'">
<LogicalName>%(ReferenceCopyLocalPaths.DestinationSubDirectory)%(ReferenceCopyLocalPaths.Filename)%(ReferenceCopyLocalPaths.Extension)</LogicalName>
</EmbeddedResource>
</ItemGroup>
</Target>
2) Make your Main Program.cs look like this:
[STAThreadAttribute]
public static void Main()
{
AppDomain.CurrentDomain.AssemblyResolve += OnResolveAssembly;
App.Main();
}
3) Add the OnResolveAssembly method:
private static Assembly OnResolveAssembly(object sender, ResolveEventArgs args)
{
Assembly executingAssembly = Assembly.GetExecutingAssembly();
AssemblyName assemblyName = new AssemblyName(args.Name);
var path = assemblyName.Name + ".dll";
if (assemblyName.CultureInfo.Equals(CultureInfo.InvariantCulture) == false) path = String.Format(#"{0}\{1}", assemblyName.CultureInfo, path);
using (Stream stream = executingAssembly.GetManifestResourceStream(path))
{
if (stream == null) return null;
var assemblyRawBytes = new byte[stream.Length];
stream.Read(assemblyRawBytes, 0, assemblyRawBytes.Length);
return Assembly.Load(assemblyRawBytes);
}
}

You could add the DLLs as embedded resources, and then have your program unpack them into the application directory on startup (after checking to see if they're there already).
Setup files are so easy to make, though, that I don't think this would be worth it.
EDIT: This technique would be easy with .NET assemblies. With non-.NET DLLs it would be a lot more work (you'd have to figure out where to unpack the files and register them and so on).

Another product that can handle this elegantly is SmartAssembly, at SmartAssembly.com. This product will, in addition to merging all dependencies into a single DLL, (optionally) obfuscate your code, remove extra meta-data to reduce the resulting file size, and can also actually optimize the IL to increase runtime performance.
There is also some kind of global exception handling/reporting feature it adds to your software (if desired) that could be useful. I believe it also has a command-line API so you can make it part of your build process.

Neither the ILMerge approach nor Lars Holm Jensen's handling the AssemblyResolve event will work for a plugin host. Say executable H loads assembly P dynamically and accesses it via interface IP defined in an separate assembly. To embed IP into H one shall need a little modification to Lars's code:
Dictionary<string, Assembly> loaded = new Dictionary<string,Assembly>();
AppDomain.CurrentDomain.AssemblyResolve += (sender, args) =>
{ Assembly resAssembly;
string dllName = args.Name.Contains(",") ? args.Name.Substring(0, args.Name.IndexOf(',')) : args.Name.Replace(".dll","");
dllName = dllName.Replace(".", "_");
if ( !loaded.ContainsKey( dllName ) )
{ if (dllName.EndsWith("_resources")) return null;
System.Resources.ResourceManager rm = new System.Resources.ResourceManager(GetType().Namespace + ".Properties.Resources", System.Reflection.Assembly.GetExecutingAssembly());
byte[] bytes = (byte[])rm.GetObject(dllName);
resAssembly = System.Reflection.Assembly.Load(bytes);
loaded.Add(dllName, resAssembly);
}
else
{ resAssembly = loaded[dllName]; }
return resAssembly;
};
The trick to handle repeated attempts to resolve the same assembly and return the existing one instead of creating a new instance.
EDIT:
Lest it spoil .NET's serialization, make sure to return null for all assemblies not embedded in yours, thereby defaulting to the standard behaviour. You can get a list of these libraries by:
static HashSet<string> IncludedAssemblies = new HashSet<string>();
string[] resources = System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceNames();
for(int i = 0; i < resources.Length; i++)
{ IncludedAssemblies.Add(resources[i]); }
and just return null if the passed assembly does not belong to IncludedAssemblies .

It may sound simplistic, but WinRar gives the option to compress a bunch of files to a self-extracting executable.
It has lots of configurable options: final icon, extract files to given path, file to execute after extraction, custom logo/texts for popup shown during extraction, no popup window at all, license agreement text, etc.
May be useful in some cases.

I use the csc.exe compiler called from a .vbs script.
In your xyz.cs script, add the following lines after the directives (my example is for the Renci SSH):
using System;
using Renci;//FOR THE SSH
using System.Net;//FOR THE ADDRESS TRANSLATION
using System.Reflection;//FOR THE Assembly
//+ref>"C:\Program Files (x86)\Microsoft\ILMerge\Renci.SshNet.dll"
//+res>"C:\Program Files (x86)\Microsoft\ILMerge\Renci.SshNet.dll"
//+ico>"C:\Program Files (x86)\Microsoft CAPICOM 2.1.0.2 SDK\Samples\c_sharp\xmldsig\resources\Traffic.ico"
The ref, res and ico tags will be picked up by the .vbs script below to form the csc command.
Then add the assembly resolver caller in the Main:
public static void Main(string[] args)
{
AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve);
.
...and add the resolver itself somewhere in the class:
static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
{
String resourceName = new AssemblyName(args.Name).Name + ".dll";
using (var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName))
{
Byte[] assemblyData = new Byte[stream.Length];
stream.Read(assemblyData, 0, assemblyData.Length);
return Assembly.Load(assemblyData);
}
}
I name the vbs script to match the .cs filename (e.g. ssh.vbs looks for ssh.cs); this makes running the script numerous times a lot easier, but if you aren't an idiot like me then a generic script could pick up the target .cs file from a drag-and-drop:
Dim name_,oShell,fso
Set oShell = CreateObject("Shell.Application")
Set fso = CreateObject("Scripting.fileSystemObject")
'TAKE THE VBS SCRIPT NAME AS THE TARGET FILE NAME
'################################################
name_ = Split(wscript.ScriptName, ".")(0)
'GET THE EXTERNAL DLL's AND ICON NAMES FROM THE .CS FILE
'#######################################################
Const OPEN_FILE_FOR_READING = 1
Set objInputFile = fso.OpenTextFile(name_ & ".cs", 1)
'READ EVERYTHING INTO AN ARRAY
'#############################
inputData = Split(objInputFile.ReadAll, vbNewline)
For each strData In inputData
if left(strData,7)="//+ref>" then
csc_references = csc_references & " /reference:" & trim(replace(strData,"//+ref>","")) & " "
end if
if left(strData,7)="//+res>" then
csc_resources = csc_resources & " /resource:" & trim(replace(strData,"//+res>","")) & " "
end if
if left(strData,7)="//+ico>" then
csc_icon = " /win32icon:" & trim(replace(strData,"//+ico>","")) & " "
end if
Next
objInputFile.Close
'COMPILE THE FILE
'################
oShell.ShellExecute "c:\windows\microsoft.net\framework\v3.5\csc.exe", "/warn:1 /target:exe " & csc_references & csc_resources & csc_icon & " " & name_ & ".cs", "", "runas", 2
WScript.Quit(0)

If you are using .NET Core 3.0
You can do this with the dotnet publish command with PublishSingleFile property:
dotnet publish -r win-x64 -c Release /p:PublishSingleFile=true
The only downside is you end up with a single EXE file with a huge size.

It's possible but not all that easy, to create a hybrid native/managed assembly in C#. Were you using C++ instead it'd be a lot easier, as the Visual C++ compiler can create hybrid assemblies as easily as anything else.
Unless you have a strict requirement to produce a hybrid assembly, I'd agree with MusiGenesis that this isn't really worth the trouble to do with C#. If you need to do it, perhaps look at moving to C++/CLI instead.

Generally you would need some form of post build tool to perform an assembly merge like you are describing. There is a free tool called Eazfuscator (eazfuscator.blogspot.com/) which is designed for bytecode mangling that also handles assembly merging. You can add this into a post build command line with Visual Studio to merge your assemblies, but your mileage will vary due to issues that will arise in any non trival assembly merging scenarios.
You could also check to see if the build make untility NANT has the ability to merge assemblies after building, but I am not familiar enough with NANT myself to say whether the functionality is built in or not.
There are also many many Visual Studio plugins that will perform assembly merging as part of building the application.
Alternatively if you don't need this to be done automatically, there are a number of tools like ILMerge that will merge .net assemblies into a single file.
The biggest issue I've had with merging assemblies is if they use any similar namespaces. Or worse, reference different versions of the same dll (my problems were generally with the NUnit dll files).

Try this:
https://github.com/ytk2128/dll-merger
here you can merge all 32 bit dlls/exe - even its not ".net" dlls - so for me better then ilmerge for example ...

Packing third party DLL into Windows service [duplicate]

Is it possible to embed a pre-existing DLL into a compiled C# executable (so that you only have one file to distribute)? If it is possible, how would one go about doing it?
Normally, I'm cool with just leaving the DLLs outside and having the setup program handle everything, but there have been a couple of people at work who have asked me this and I honestly don't know.

I highly recommend to use Costura.Fody - by far the best and easiest way to embed resources in your assembly. It's available as NuGet package.
Install-Package Costura.Fody
After adding it to the project, it will automatically embed all references that are copied to the output directory into your main assembly. You might want to clean the embedded files by adding a target to your project:
Install-CleanReferencesTarget
You'll also be able to specify whether to include the pdb's, exclude certain assemblies, or extracting the assemblies on the fly. As far as I know, also unmanaged assemblies are supported.
Update
Currently, some people are trying to add support for DNX.
Update 2
For the lastest Fody version, you will need to have MSBuild 16 (so Visual Studio 2019). Fody version 4.2.1 will do MSBuild 15. (reference: Fody is only supported on MSBuild 16 and above. Current version: 15)

Just right-click your project in Visual Studio, choose Project Properties -> Resources -> Add Resource -> Add Existing File…
And include the code below to your App.xaml.cs or equivalent.
public App()
{
AppDomain.CurrentDomain.AssemblyResolve +=new ResolveEventHandler(CurrentDomain_AssemblyResolve);
}
System.Reflection.Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
{
string dllName = args.Name.Contains(',') ? args.Name.Substring(0, args.Name.IndexOf(',')) : args.Name.Replace(".dll","");
dllName = dllName.Replace(".", "_");
if (dllName.EndsWith("_resources")) return null;
System.Resources.ResourceManager rm = new System.Resources.ResourceManager(GetType().Namespace + ".Properties.Resources", System.Reflection.Assembly.GetExecutingAssembly());
byte[] bytes = (byte[])rm.GetObject(dllName);
return System.Reflection.Assembly.Load(bytes);
}
Here's my original blog post:
http://codeblog.larsholm.net/2011/06/embed-dlls-easily-in-a-net-assembly/

If they're actually managed assemblies, you can use ILMerge. For native DLLs, you'll have a bit more work to do.
See also: How can a C++ windows dll be merged into a C# application exe?

Yes, it is possible to merge .NET executables with libraries. There are multiple tools available to get the job done:
ILMerge is a utility that can be used to merge multiple .NET assemblies into a single assembly.
Mono mkbundle, packages an exe and all assemblies with libmono into a single binary package.
IL-Repack is a FLOSS alterantive to ILMerge, with some additional features.
In addition this can be combined with the Mono Linker, which does remove unused code and therefor makes the resulting assembly smaller.
Another possibility is to use .NETZ, which does not only allow compressing of an assembly, but also can pack the dlls straight into the exe. The difference to the above mentioned solutions is that .NETZ does not merge them, they stay separate assemblies but are packed into one package.
.NETZ is a open source tool that compresses and packs the Microsoft .NET Framework executable (EXE, DLL) files in order to make them smaller.

ILMerge can combine assemblies to one single assembly provided the assembly has only managed code. You can use the commandline app, or add reference to the exe and programmatically merge. For a GUI version there is Eazfuscator, and also .Netz both of which are free. Paid apps include BoxedApp and SmartAssembly.
If you have to merge assemblies with unmanaged code, I would suggest SmartAssembly. I never had hiccups with SmartAssembly but with all others. Here, it can embed the required dependencies as resources to your main exe.
You can do all this manually not needing to worry if assembly is managed or in mixed mode by embedding dll to your resources and then relying on AppDomain's Assembly ResolveHandler. This is a one stop solution by adopting the worst case, ie assemblies with unmanaged code.
static void Main()
{
AppDomain.CurrentDomain.AssemblyResolve += (sender, args) =>
{
string assemblyName = new AssemblyName(args.Name).Name;
if (assemblyName.EndsWith(".resources"))
return null;
string dllName = assemblyName + ".dll";
string dllFullPath = Path.Combine(GetMyApplicationSpecificPath(), dllName);
using (Stream s = Assembly.GetEntryAssembly().GetManifestResourceStream(typeof(Program).Namespace + ".Resources." + dllName))
{
byte[] data = new byte[stream.Length];
s.Read(data, 0, data.Length);
//or just byte[] data = new BinaryReader(s).ReadBytes((int)s.Length);
File.WriteAllBytes(dllFullPath, data);
}
return Assembly.LoadFrom(dllFullPath);
};
}
The key here is to write the bytes to a file and load from its location. To avoid chicken and egg problem, you have to ensure you declare the handler before accessing assembly and that you do not access the assembly members (or instantiate anything that has to deal with the assembly) inside the loading (assembly resolving) part. Also take care to ensure GetMyApplicationSpecificPath() is not any temp directory since temp files could be attempted to get erased by other programs or by yourself (not that it will get deleted while your program is accessing the dll, but at least its a nuisance. AppData is good location). Also note that you have to write the bytes each time, you cant load from location just 'cos the dll already resides there.
For managed dlls, you need not write bytes, but directly load from the location of the dll, or just read the bytes and load the assembly from memory. Like this or so:
using (Stream s = Assembly.GetEntryAssembly().GetManifestResourceStream(typeof(Program).Namespace + ".Resources." + dllName))
{
byte[] data = new byte[stream.Length];
s.Read(data, 0, data.Length);
return Assembly.Load(data);
}
//or just
return Assembly.LoadFrom(dllFullPath); //if location is known.
If the assembly is fully unmanaged, you can see this link or this as to how to load such dlls.

.NET Core 3.0 natively supports compiling to a single .exe
The feature is enabled by the usage of the following property in your project file (.csproj):
<PropertyGroup>
<PublishSingleFile>true</PublishSingleFile>
</PropertyGroup>
This is done without any external tool.
See my answer for this question for further details.

The excerpt by Jeffrey Richter is very good. In short, add the libraries as embedded resources and add a callback before anything else. Here is a version of the code (found in the comments of his page) that I put at the start of Main method for a console app (just make sure that any calls that use the libraries are in a different method to Main).
AppDomain.CurrentDomain.AssemblyResolve += (sender, bargs) =>
{
String dllName = new AssemblyName(bargs.Name).Name + ".dll";
var assem = Assembly.GetExecutingAssembly();
String resourceName = assem.GetManifestResourceNames().FirstOrDefault(rn => rn.EndsWith(dllName));
if (resourceName == null) return null; // Not found, maybe another handler will find it
using (var stream = assem.GetManifestResourceStream(resourceName))
{
Byte[] assemblyData = new Byte[stream.Length];
stream.Read(assemblyData, 0, assemblyData.Length);
return Assembly.Load(assemblyData);
}
};

To expand on #Bobby's asnwer above. You can edit your .csproj to use IL-Repack to automatically package all files into a single assembly when you build.
Install the nuget ILRepack.MSBuild.Task package with Install-Package ILRepack.MSBuild.Task
Edit the AfterBuild section of your .csproj
Here is a simple sample that merges ExampleAssemblyToMerge.dll into your project output.
<!-- ILRepack -->
<Target Name="AfterBuild" Condition="'$(Configuration)' == 'Release'">
<ItemGroup>
<InputAssemblies Include="$(OutputPath)\$(AssemblyName).exe" />
<InputAssemblies Include="$(OutputPath)\ExampleAssemblyToMerge.dll" />
</ItemGroup>
<ILRepack
Parallel="true"
Internalize="true"
InputAssemblies="#(InputAssemblies)"
TargetKind="Exe"
OutputFile="$(OutputPath)\$(AssemblyName).exe"
/>
</Target>

The following method DO NOT use external tools and AUTOMATICALLY include all needed DLL (no manual action required, everything done at compilation)
I read a lot of answer here saying to use ILMerge, ILRepack or Jeffrey Ritcher method but none of that worked with WPF applications nor was easy to use.
When you have a lot of DLL it can be hard to manually include the one you need in your exe. The best method i found was explained by Wegged here on StackOverflow
Copy pasted his answer here for clarity (all credit to Wegged)
1) Add this to your .csproj file:
<Target Name="AfterResolveReferences">
<ItemGroup>
<EmbeddedResource Include="#(ReferenceCopyLocalPaths)" Condition="'%(ReferenceCopyLocalPaths.Extension)' == '.dll'">
<LogicalName>%(ReferenceCopyLocalPaths.DestinationSubDirectory)%(ReferenceCopyLocalPaths.Filename)%(ReferenceCopyLocalPaths.Extension)</LogicalName>
</EmbeddedResource>
</ItemGroup>
</Target>
2) Make your Main Program.cs look like this:
[STAThreadAttribute]
public static void Main()
{
AppDomain.CurrentDomain.AssemblyResolve += OnResolveAssembly;
App.Main();
}
3) Add the OnResolveAssembly method:
private static Assembly OnResolveAssembly(object sender, ResolveEventArgs args)
{
Assembly executingAssembly = Assembly.GetExecutingAssembly();
AssemblyName assemblyName = new AssemblyName(args.Name);
var path = assemblyName.Name + ".dll";
if (assemblyName.CultureInfo.Equals(CultureInfo.InvariantCulture) == false) path = String.Format(#"{0}\{1}", assemblyName.CultureInfo, path);
using (Stream stream = executingAssembly.GetManifestResourceStream(path))
{
if (stream == null) return null;
var assemblyRawBytes = new byte[stream.Length];
stream.Read(assemblyRawBytes, 0, assemblyRawBytes.Length);
return Assembly.Load(assemblyRawBytes);
}
}

You could add the DLLs as embedded resources, and then have your program unpack them into the application directory on startup (after checking to see if they're there already).
Setup files are so easy to make, though, that I don't think this would be worth it.
EDIT: This technique would be easy with .NET assemblies. With non-.NET DLLs it would be a lot more work (you'd have to figure out where to unpack the files and register them and so on).

Another product that can handle this elegantly is SmartAssembly, at SmartAssembly.com. This product will, in addition to merging all dependencies into a single DLL, (optionally) obfuscate your code, remove extra meta-data to reduce the resulting file size, and can also actually optimize the IL to increase runtime performance.
There is also some kind of global exception handling/reporting feature it adds to your software (if desired) that could be useful. I believe it also has a command-line API so you can make it part of your build process.

Neither the ILMerge approach nor Lars Holm Jensen's handling the AssemblyResolve event will work for a plugin host. Say executable H loads assembly P dynamically and accesses it via interface IP defined in an separate assembly. To embed IP into H one shall need a little modification to Lars's code:
Dictionary<string, Assembly> loaded = new Dictionary<string,Assembly>();
AppDomain.CurrentDomain.AssemblyResolve += (sender, args) =>
{ Assembly resAssembly;
string dllName = args.Name.Contains(",") ? args.Name.Substring(0, args.Name.IndexOf(',')) : args.Name.Replace(".dll","");
dllName = dllName.Replace(".", "_");
if ( !loaded.ContainsKey( dllName ) )
{ if (dllName.EndsWith("_resources")) return null;
System.Resources.ResourceManager rm = new System.Resources.ResourceManager(GetType().Namespace + ".Properties.Resources", System.Reflection.Assembly.GetExecutingAssembly());
byte[] bytes = (byte[])rm.GetObject(dllName);
resAssembly = System.Reflection.Assembly.Load(bytes);
loaded.Add(dllName, resAssembly);
}
else
{ resAssembly = loaded[dllName]; }
return resAssembly;
};
The trick to handle repeated attempts to resolve the same assembly and return the existing one instead of creating a new instance.
EDIT:
Lest it spoil .NET's serialization, make sure to return null for all assemblies not embedded in yours, thereby defaulting to the standard behaviour. You can get a list of these libraries by:
static HashSet<string> IncludedAssemblies = new HashSet<string>();
string[] resources = System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceNames();
for(int i = 0; i < resources.Length; i++)
{ IncludedAssemblies.Add(resources[i]); }
and just return null if the passed assembly does not belong to IncludedAssemblies .

It may sound simplistic, but WinRar gives the option to compress a bunch of files to a self-extracting executable.
It has lots of configurable options: final icon, extract files to given path, file to execute after extraction, custom logo/texts for popup shown during extraction, no popup window at all, license agreement text, etc.
May be useful in some cases.

I use the csc.exe compiler called from a .vbs script.
In your xyz.cs script, add the following lines after the directives (my example is for the Renci SSH):
using System;
using Renci;//FOR THE SSH
using System.Net;//FOR THE ADDRESS TRANSLATION
using System.Reflection;//FOR THE Assembly
//+ref>"C:\Program Files (x86)\Microsoft\ILMerge\Renci.SshNet.dll"
//+res>"C:\Program Files (x86)\Microsoft\ILMerge\Renci.SshNet.dll"
//+ico>"C:\Program Files (x86)\Microsoft CAPICOM 2.1.0.2 SDK\Samples\c_sharp\xmldsig\resources\Traffic.ico"
The ref, res and ico tags will be picked up by the .vbs script below to form the csc command.
Then add the assembly resolver caller in the Main:
public static void Main(string[] args)
{
AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve);
.
...and add the resolver itself somewhere in the class:
static Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
{
String resourceName = new AssemblyName(args.Name).Name + ".dll";
using (var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName))
{
Byte[] assemblyData = new Byte[stream.Length];
stream.Read(assemblyData, 0, assemblyData.Length);
return Assembly.Load(assemblyData);
}
}
I name the vbs script to match the .cs filename (e.g. ssh.vbs looks for ssh.cs); this makes running the script numerous times a lot easier, but if you aren't an idiot like me then a generic script could pick up the target .cs file from a drag-and-drop:
Dim name_,oShell,fso
Set oShell = CreateObject("Shell.Application")
Set fso = CreateObject("Scripting.fileSystemObject")
'TAKE THE VBS SCRIPT NAME AS THE TARGET FILE NAME
'################################################
name_ = Split(wscript.ScriptName, ".")(0)
'GET THE EXTERNAL DLL's AND ICON NAMES FROM THE .CS FILE
'#######################################################
Const OPEN_FILE_FOR_READING = 1
Set objInputFile = fso.OpenTextFile(name_ & ".cs", 1)
'READ EVERYTHING INTO AN ARRAY
'#############################
inputData = Split(objInputFile.ReadAll, vbNewline)
For each strData In inputData
if left(strData,7)="//+ref>" then
csc_references = csc_references & " /reference:" & trim(replace(strData,"//+ref>","")) & " "
end if
if left(strData,7)="//+res>" then
csc_resources = csc_resources & " /resource:" & trim(replace(strData,"//+res>","")) & " "
end if
if left(strData,7)="//+ico>" then
csc_icon = " /win32icon:" & trim(replace(strData,"//+ico>","")) & " "
end if
Next
objInputFile.Close
'COMPILE THE FILE
'################
oShell.ShellExecute "c:\windows\microsoft.net\framework\v3.5\csc.exe", "/warn:1 /target:exe " & csc_references & csc_resources & csc_icon & " " & name_ & ".cs", "", "runas", 2
WScript.Quit(0)

If you are using .NET Core 3.0
You can do this with the dotnet publish command with PublishSingleFile property:
dotnet publish -r win-x64 -c Release /p:PublishSingleFile=true
The only downside is you end up with a single EXE file with a huge size.

It's possible but not all that easy, to create a hybrid native/managed assembly in C#. Were you using C++ instead it'd be a lot easier, as the Visual C++ compiler can create hybrid assemblies as easily as anything else.
Unless you have a strict requirement to produce a hybrid assembly, I'd agree with MusiGenesis that this isn't really worth the trouble to do with C#. If you need to do it, perhaps look at moving to C++/CLI instead.

Generally you would need some form of post build tool to perform an assembly merge like you are describing. There is a free tool called Eazfuscator (eazfuscator.blogspot.com/) which is designed for bytecode mangling that also handles assembly merging. You can add this into a post build command line with Visual Studio to merge your assemblies, but your mileage will vary due to issues that will arise in any non trival assembly merging scenarios.
You could also check to see if the build make untility NANT has the ability to merge assemblies after building, but I am not familiar enough with NANT myself to say whether the functionality is built in or not.
There are also many many Visual Studio plugins that will perform assembly merging as part of building the application.
Alternatively if you don't need this to be done automatically, there are a number of tools like ILMerge that will merge .net assemblies into a single file.
The biggest issue I've had with merging assemblies is if they use any similar namespaces. Or worse, reference different versions of the same dll (my problems were generally with the NUnit dll files).

Try this:
https://github.com/ytk2128/dll-merger
here you can merge all 32 bit dlls/exe - even its not ".net" dlls - so for me better then ilmerge for example ...