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Forcing .Extensions namespace to load when embedded DLL will need it

I'm building a utility that uses Microsoft's DACPAC libraries. For the purpose of this tool, I want to embed all requisite libraries in the executable. It appears that when I execute DacServices.GenerateDeployScript() it's trying to use the Microsoft.SqlServer.Dac.Extensions library. The library is also embedded, but perhaps isn't being resolved with my EventHandler the way other DLLs are. My EventHandler is like this:
private static Assembly ResolveEventHandler(Object sender, ResolveEventArgs args)
{
//Debugger.Break();
String dllName = new AssemblyName(args.Name).Name + ".dll";
var assem = Assembly.GetExecutingAssembly();
String resourceName = assem.GetManifestResourceNames().FirstOrDefault(rn => rn.EndsWith(dllName));
if (resourceName == null) return null;
using (var stream = assem.GetManifestResourceStream(resourceName))
{
Byte[] assemblyData = new Byte[stream.Length];
stream.Read(assemblyData, 0, assemblyData.Length);
return Assembly.Load(assemblyData);
}
}
This works for resolving other items, but I believe that the likely issue is that the Microsoft.SqlServer.Dac namespace is making an execution time call to the .Extensions namespace and isn't able to resolve the namespace or the methods in it. I could be wrong, but I'm not sure what else could be the cause.
The calls to methods and classes in .Dac itself are being handled fine, so I know the EventHandler is working properly. I'm not really sure what to do and would appreciate any guidance. I've tried using Microsoft.SqlServer.Dac.Extenions at the top of the .cs file, but since I don't directly call anything in that namespace, it's grey and probably is ignored by the compiler.
Thanks!
Update:
I made a call to the .Extensions namespace in the code to force it to be read into memory prior to the failing call, though it appears that it already was. I set a breakpoint where the resolver kicks off. Just prior to it failing, it's trying to resolve .resource for each DLL, e.g. Microsoft.SqlServer.Dac.resource and Microsoft.SqlServer.TransactSql.ScriptDom.resource - all for DLLs embedded in the executable. The resolver doesn't see anything because there are no .resource files in the project, so nothing compiled into the manifest. Aren't these supposed to just be resident in memory while a DLL is being utilized? When the DLLs are all present in the same directory as the .exe, it functions fine, and also doesn't create temporary .resource files in the directory, so I'm unsure what I'm looking to resolve.
Update 2:
Using a PDB of the DAC libraries, it appears the failing line is:
IOperation operation = DacServices.CreateDeploymentArtifactGenerationOperation(OperationResources.GenerateDeployScriptCaption, (ErrorManager errorManager) => this.CreatePackageToDatabaseDeployment(package.PackageSource, targetDatabaseName, dacDeployOption, errorManager), (IDeploymentController controller, DeploymentPlan plan, ErrorManager errorManager) => DacServices.WriteDeploymentScript(streamWriter, controller, plan, errorManager), cancellationToken1, dacLoggingContext);
And the resulting exceptions are:
The extension type Microsoft.SqlServer.Dac.Deployment.Internal.InternalDeploymentPlanExecutor could not be instantiated.
and
The extension type Microsoft.SqlServer.Dac.Deployment.Internal.InternalDeploymentPlanModifier could not be instantiated.

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?

Is it possible to internalize/IL-merge a single C# class?

I have an app with a reference to a rather large library DLL (let's call it lib.dll), but it only uses a single class from it (let's call this Helper).
lib.dll has additional transitive references which are all copied to the bin folder of my project upon compilation.
I would seriously like to avoid that overhead and find a way to "copy" or "cross-compile" or "merge" the code that makes up Helper into my main project.
Are there any possibilities for doing so? I would like to avoid IL-merging lib.dll in its entirity.

In some situations you can just embed the third party dlls as embedded resources and resolve the references yourself, as Jeffrey Richter described here.
In a nutshell, in your entry point:
AppDomain.CurrentDomain.AssemblyResolve += (sender, args) => {
string name = new AssemblyName(args.Name).Name;
// Either hardcode the appropriate namespace or retrieve it at runtime in a way that makes sense for your project.
string resourceName = string.Concat("My.Namespace.Resources.", name, ".dll");
using(var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName)) {
var buffer = new byte[stream.Length];
stream.Read(buffer, 0, buffer.Length);
return Assembly.Load(buffer);
}
};

If you were using .NET Core the new .NET Linker would be an option. Otherwise, license permitting, and if the class you use does not have too many dependencies and the dll is not obfuscated, you could just copy the code to your application by decompiling the dll with IL Spy

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 ...

How to declare type in an Imported or Embed Resource DLL

I'm actually looking for solution merge all DLL and EXE into single file.
I have asked a question at here:
How to use an DLL load from Embed Resource?
and I received suggestion that I can link the DLL as embed resource, then write the embed DLL file into memory and use DLLImport to import the DLL.
I followed the instructions here:
http://weblogs.asp.net/ralfw/archive/2007/02/04/single-assembly-deployment-of-managed-and-unmanaged-code.aspx
and below is what I have done:
[DllImport("System.Data.SQLite.dll")]
public static SQLiteConnection sqLiteConnection1 = new SQLiteConnection();
public Form1()
{
ResourceExtractor.ExtractResourceToFile("MyApp.System.Data.SQLite.dll", "System.Data.SQLite.dll");
}
public static class ResourceExtractor
{
public static void ExtractResourceToFile(string resourceName, string filename)
{
if (!System.IO.File.Exists(filename))
using (System.IO.Stream s = System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName))
using (System.IO.FileStream fs = new System.IO.FileStream(filename, System.IO.FileMode.Create))
{
byte[] b = new byte[s.Length];
s.Read(b, 0, b.Length);
fs.Write(b, 0, b.Length);
}
}
}
but Visual Studio says that this block creates an error:
[DllImport("System.Data.SQLite.dll")]
public static SQLiteConnection sqLiteConnection1 = new SQLiteConnection();
Error 1 Attribute 'DllImport' is not valid on this declaration type. It is only valid on 'method' declarations.
How to declare the type inside that DLL?
Thanks you very much.

The DllImport attribute is used to declare methods from unmanaged DLLs.
Since System.Data.SQLite.dll is a managed assembly, what you need to do, after saving your assembly to disk, is to load it via Reflection, something like:
using System.Data;
...
var assembly = Assembly.LoadFile(#"path\to\System.Data.SQLite.dll");
var type = assembly.GetType("System.Data.SQLite.SQLiteConnection");
IDbConnection connection = (IDbConnection)Activator.CreateInstance(type);
Hope that helps.

If you want to stuff managed assemblies and the exe in one file, I suggest you look at ILMerge.
It is much easier to use than manually doing things with resources.

DllImport is only for native DLLs.
On embedding managed DLLs you have several options:
use ILMerge (free)
For howto see here and here
OR
use some tool like SmartAssembly (commercial)
it can embed and merge among other things (no need to change your source code)
OR
code that yourself in less than 10 lines (free but minimal source code change)
mark all needed dependencies as "embedded resource" - this way they are included in the EXE file... you need to setup an AssemblyResolve handler which at runtime reads from Resources and returns the needed DLLs to the .NET runtime...
On using a type from such an Assembly see these links (they including reference material AND some sample code etc.):
http://msdn.microsoft.com/en-us/library/system.activator.createinstance.aspx
https://stackoverflow.com/a/57450/847363
http://msdn.microsoft.com/en-us/library/h538bck7.aspx (loads an ssembly from a byte array so there is no need to write that assembly to the filesystem)
http://msdn.microsoft.com/en-us/library/system.reflection.assembly.gettype.aspx
http://www.codeproject.com/Articles/32828/Using-Reflection-to-load-unreferenced-assemblies-a