Using UpdateResource in C#?

Question

I\'m trying to change the icon of external executable programmatically. I\'ve googled and found much information about this problem using C++. Basically, I need to use Begin

Answer 1

I managed to get this working in pure C# using ResourceHacker and this posting as an example. Just use a regular .ico as input. In ResourceHacker (http://www.angusj.com/resourcehacker/) you will see the icon identifier (in my case 1) and the language identifier (in my case 1043):

I used this code:

internal class IconChanger
{

    #region IconReader
    public class Icons : List
    {
        public byte[] ToGroupData(int startindex = 1)
        {
            using (var ms = new MemoryStream())
            using (var writer = new BinaryWriter(ms))
            {
                var i = 0;

                writer.Write((ushort)0);  //reserved, must be 0
                writer.Write((ushort)1);  // type is 1 for icons
                writer.Write((ushort)this.Count);  // number of icons in structure(1)

                foreach (var icon in this)
                {

                    writer.Write(icon.Width);
                    writer.Write(icon.Height);
                    writer.Write(icon.Colors);

                    writer.Write((byte)0); // reserved, must be 0
                    writer.Write(icon.ColorPlanes);

                    writer.Write(icon.BitsPerPixel);

                    writer.Write(icon.Size);

                    writer.Write((ushort)(startindex + i));

                    i++;

                }
                ms.Position = 0;

                return ms.ToArray();
            }
        }
    }

    public class Icon
    {

        public byte Width { get; set; }
        public byte Height { get; set; }
        public byte Colors { get; set; }

        public uint Size { get; set; }

        public uint Offset { get; set; }

        public ushort ColorPlanes { get; set; }

        public ushort BitsPerPixel { get; set; }

        public byte[] Data { get; set; }

    }

    public class IconReader
    {

        public Icons Icons = new Icons();

        public IconReader(Stream input)
        {
            using (BinaryReader reader = new BinaryReader(input))
            {
                reader.ReadUInt16(); // ignore. Should be 0
                var type = reader.ReadUInt16();
                if (type != 1)
                {
                    throw new Exception("Invalid type. The stream is not an icon file");
                }
                var num_of_images = reader.ReadUInt16();

                for (var i = 0; i < num_of_images; i++)
                {
                    var width = reader.ReadByte();
                    var height = reader.ReadByte();
                    var colors = reader.ReadByte();
                    reader.ReadByte(); // ignore. Should be 0

                    var color_planes = reader.ReadUInt16(); // should be 0 or 1

                    var bits_per_pixel = reader.ReadUInt16();

                    var size = reader.ReadUInt32();

                    var offset = reader.ReadUInt32();

                    this.Icons.Add(new Icon()
                    {
                        Colors = colors,
                        Height = height,
                        Width = width,
                        Offset = offset,
                        Size = size,
                        ColorPlanes = color_planes,
                        BitsPerPixel = bits_per_pixel
                    });
                }

                // now get the Data
                foreach (var icon in Icons)
                {
                    if (reader.BaseStream.Position < icon.Offset)
                    {
                        var dummy_bytes_to_read = (int)(icon.Offset - reader.BaseStream.Position);
                        reader.ReadBytes(dummy_bytes_to_read);
                    }

                    var data = reader.ReadBytes((int)icon.Size);

                    icon.Data = data;
                }

            }
        }

    }
    #endregion

    [DllImport("kernel32.dll", SetLastError = true)]
    static extern int UpdateResource(IntPtr hUpdate, uint lpType, ushort lpName, ushort wLanguage, byte[] lpData, uint cbData);

    [DllImport("kernel32.dll", SetLastError = true)]
    static extern IntPtr BeginUpdateResource(string pFileName, [MarshalAs(UnmanagedType.Bool)]bool bDeleteExistingResources);

    [DllImport("kernel32.dll", SetLastError = true)]
    static extern bool EndUpdateResource(IntPtr hUpdate, bool fDiscard);

    public enum ICResult
    {
        Success,
        FailBegin,
        FailUpdate,
        FailEnd
    }

    const uint RT_ICON = 3;
    const uint RT_GROUP_ICON = 14;

    public ICResult ChangeIcon(string exeFilePath, string iconFilePath)
    {
        using (FileStream fs = new FileStream(iconFilePath, FileMode.Open, FileAccess.Read))
        {
            var reader = new IconReader(fs);

            var iconChanger = new IconChanger();
            return iconChanger.ChangeIcon(exeFilePath, reader.Icons);
        }
    }

    public ICResult ChangeIcon(string exeFilePath, Icons icons)
    {
        // Load executable
        IntPtr handleExe = BeginUpdateResource(exeFilePath, false);

        if (handleExe == null) return ICResult.FailBegin;

        ushort startindex = 1;
        ushort index = startindex;
        ICResult result = ICResult.Success;

        var ret = 1;

        foreach (var icon in icons)
        {
            // Replace the icon
            // todo :Improve the return value handling of UpdateResource
            ret = UpdateResource(handleExe, RT_ICON, index, 0, icon.Data, icon.Size);

            index++;
        }

        var groupdata = icons.ToGroupData();

        // todo :Improve the return value handling of UpdateResource
        ret = UpdateResource(handleExe, RT_GROUP_ICON, startindex, 0, groupdata, (uint)groupdata.Length);
        if (ret == 1)
        {
            if (EndUpdateResource(handleExe, false))
                result = ICResult.Success;
            else
                result = ICResult.FailEnd;
        }
        else
            result = ICResult.FailUpdate;

        return result;
    }
}