Embedding DLL's into .exe in in Visual C# 2010

Question

I'm working on a C# program that uses iTextSharp.dll and WebCam_Capture.dll. When I build the program, it creates executable in the debug folder and it also copies these two dll's to the debug folder as expected. I want to merge them into a single executable, however I failed. These two libraries are visible in the references normally in the solution explorer. I also add them as resources. Executable size got bigger which equals the sum of three files, nevertheless the executable still requires these libraries in its directory... I played with "build action" property of the resource files but no change. I also tried ILmerge but it gave me an error. so what should I do?

Update: This is what I get from ILmerge:

An exception occurred during merging:
Unresolved assembly reference not allowed: System.Core.
at System.Compiler.Ir2md.GetAssemblyRefIndex(AssemblyNode assembly)
   at System.Compiler.Ir2md.GetTypeRefIndex(TypeNode type)

It is just a windows application by the way, a form to be filled and printed as pdf with a photo taken via webcam if available. Thanks all!

Solution 1

You can use ILMerge to merge multiple assemblies together. You've already said you did this, and you've received an error. Though I don't know why, you can use an alternative: if the libraries are open source (and their licenses are compatible with yours), you can download the source code, add it to your project and compile. This will result in a single assembly.

The ILMerge page also lists Jeffrey Richter's blog as yet another alternative to solve your issue:

Many applications consist of an EXE file that depends on many DLL files. When deploying this application, all the files must be deployed. However, there is a technique that you can use to deploy just a single EXE file. First, identify all the DLL files that your EXE file depends on that do not ship as part of the Microsoft .NET Framework itself. Then add these DLLs to your Visual Studio project. For each DLL file you add, display its properties and change its “Build Action” to “Embedded Resource.” This causes the C# compiler to embed the DLL file(s) into your EXE file, and you can deploy this one EXE file.

At runtime, the CLR won’t be able to find the dependent DLL assemblies, which is a problem. To fix this, when your application initializes, register a callback method with the AppDomain’s ResolveAssembly event. The code should look something like this:

AppDomain.CurrentDomain.AssemblyResolve += (sender, args) => { 
   String resourceName = "AssemblyLoadingAndReflection." + 
       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); 
   }   
}; 

Now, the first time a thread calls a method that references a type in a dependent DLL file, the AssemblyResolve event will be raised and the callback code shown above will find the embedded DLL resource desired and load it by calling an overload of Assembly’s Load method that takes a Byte[] as an argument.

Solution 2

1. Add the DLL files to your Visual Studio project.
2. For each file go to "Properties" and set its Build Action to "Embedded Resource"
3. On your code retrive the resource using the GetManifestResourceStream("DLL_Name_Here") this returns a stream that can be loadable.
4. Write an "AssemblyResolve" event handler to load it.

Here is the code:

using System;
using System.Collections.Generic;
using System.Reflection;
using System.IO;

namespace WindowsForm
{
    public partial class Form1 : Form
    {
        Dictionary<string, Assembly> _libs = new Dictionary<string, Assembly>();            

        public Form1()
        {
            InitializeComponent();
            AppDomain.CurrentDomain.AssemblyResolve += FindDLL;
        }

        private Assembly FindDLL(object sender, ResolveEventArgs args)
        {
            string keyName = new AssemblyName(args.Name).Name;

            // If DLL is loaded then don't load it again just return
            if (_libs.ContainsKey(keyName)) return _libs[keyName];


            using (Stream stream = Assembly.GetExecutingAssembly().GetManifestResourceStream("YourNamespaceGoesHere." + keyName + ".dll"))  // <-- To find out the Namespace name go to Your Project >> Properties >> Application >> Default namespace
            {
                byte[] buffer = new BinaryReader(stream).ReadBytes((int)stream.Length);
                Assembly assembly = Assembly.Load(buffer);
                _libs[keyName] = assembly;
                return assembly;
            }
        }

        //
        // Your Methods here
        //

    }
}

Hope it helps, Pablo

Solution 3

I modified Pablo's code a little bit and it worked for me.
It was not getting the DLL's resource name correctly.

IDictionary<string, Assembly> _libs = new Dictionary<string, Assembly>();

public Form1()
{
    AppDomain.CurrentDomain.AssemblyResolve += new ResolveEventHandler(CurrentDomain_AssemblyResolve);
    InitializeComponent();
}

// dll handler
System.Reflection.Assembly CurrentDomain_AssemblyResolve(object sender, ResolveEventArgs args)
{
    string keyName = new AssemblyName(args.Name).Name;

    // If DLL is loaded then don't load it again just return
    if (_libs.ContainsKey(keyName)) return _libs[keyName];

    using (Stream stream = Assembly.GetExecutingAssembly()
           .GetManifestResourceStream(GetDllResourceName("itextsharp.dll")))  // <-- To find out the Namespace name go to Your Project >> Properties >> Application >> Default namespace
    {
        byte[] buffer = new BinaryReader(stream).ReadBytes((int)stream.Length);
        Assembly assembly = Assembly.Load(buffer);
        _libs[keyName] = assembly;
        return assembly;
    }
}

private string GetDllResourceName(string dllName)
{
    string resourceName = string.Empty;
    foreach (string name in Assembly.GetExecutingAssembly().GetManifestResourceNames())
    {
        if (name.EndsWith(dllName))
        {
            resourceName = name;
            break;
        }
    }

    return resourceName;
}

Solution 4

The answer you are looking for:

// To embed a dll in a compiled exe:
// 1 - Change the properties of the dll in References so that Copy Local=false
// 2 - Add the dll file to the project as an additional file not just a reference
// 3 - Change the properties of the file so that Build Action=Embedded Resource
// 4 - Paste this code before Application.Run in the main exe
AppDomain.CurrentDomain.AssemblyResolve += (Object sender, ResolveEventArgs args) =>
    {
        String thisExe = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name;
        System.Reflection.AssemblyName embeddedAssembly = new System.Reflection.AssemblyName(args.Name);
        String resourceName = thisExe + "." + embeddedAssembly.Name + ".dll";

        using (var stream = System.Reflection.Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName))
        {
            Byte[] assemblyData = new Byte[stream.Length];
            stream.Read(assemblyData, 0, assemblyData.Length);
            return System.Reflection.Assembly.Load(assemblyData);
        }
    };

View more solutions

Comments

[ssube]

A word of warning: if you're building other libraries into your app, read the licenses twice over, then run them by a lawyer. You may end up catching a viral license. It's much safer to use an installer or just an archive and pack the 3 files up.

[greatmajestics]

Do we have to write this in each class?

[Pabinator]

I don't think so but you may have figure it out by now.

[Amit Bhagat]

I had to modify your code little bit to make it work, hope you don't mind :)

[mutanic]

This piece of code just save my life... 1st thing to do is to make sure we already include all the required dll, once you done just use the code above to make it work as a single exe application.

[Amit Bhagat]

glad to know it helped you.

[Andrew Barber]

Please consider including some information about your answer, rather than simply posting code. We try to provide not just 'fixes', but help people learn. You should explain what was wrong in the original code, what you did differently, and why your change(s) worked.

[Amedee Van Gasse]

iTextSharp indeed has a viral license: AGPL. So your program would have to be AGPL too. Not only when you include the source, but also when you use it as a DLL!