Use C# exe to modify resources of a different C# exe

Question

Solved! See below.

I have 2 C# applications. Application a is supposed to modify the internal resources of application b. Application b is supposed

Answer 1

Based on your assumptions you can update/add resources of your executable using Mono.Cecil library

Here are three essential methods for Resource Manipulation using Mono.Cecil:

    public static void ReplaceResource(string path, string resourceName, byte[] resource)
    {
        var definition =
            AssemblyDefinition.ReadAssembly(path);

        for (var i = 0; i < definition.MainModule.Resources.Count; i++)
            if (definition.MainModule.Resources[i].Name == resourceName)
            {
                definition.MainModule.Resources.RemoveAt(i);
                break;
            }

        var er = new EmbeddedResource(resourceName, ManifestResourceAttributes.Public, resource);
        definition.MainModule.Resources.Add(er);
        definition.Write(path);
    }

    public static void AddResource(string path, string resourceName, byte[] resource)
    {
        var definition =
            AssemblyDefinition.ReadAssembly(path);

        var er = new EmbeddedResource(resourceName, ManifestResourceAttributes.Public, resource);
        definition.MainModule.Resources.Add(er);
        definition.Write(path);
    }

    public static MemoryStream GetResource(string path, string resourceName)
    {
        var definition =
            AssemblyDefinition.ReadAssembly(path);

        foreach (var resource in definition.MainModule.Resources)
            if (resource.Name == resourceName)
            {
                var embeddedResource =(EmbeddedResource) resource;
                var stream = embeddedResource.GetResourceStream();

                var bytes = new byte[stream.Length];
                stream.Read(bytes, 0, bytes.Length);

                var memStream = new MemoryStream();
                memStream.Write(bytes,0,bytes.Length);
                memStream.Position = 0;
                return memStream;
            }

        return null;
    }

You can use GetResource method to retrieve current resource stream (Writable),

using ResourceWriter, ResourceReader or ResourceEditor classes you can read/write or modify current resource or create a new resource, then simply put it back in the executable by calling ReplaceResource or add it as a new one by calling AddResource

Here is an example of replacing an image in resource (by creating a new resource from scratch):

            var ms = new MemoryStream();
            var writer = new ResourceWriter(ms);
            writer.AddResource("good_luck",new Bitmap("good_luck.png"));
            writer.Generate();   
            ReplaceResource(@"my executale.exe", "ResourceTest.Properties.Resources.resources",ms.ToArray());

you can obtain Cecil through PM> Install-Package Mono.Cecil nuget.