Cannot convert bitmap to texture [closed]

I'm doing a little C# / OpenGL project and I can't manage to load textures properly.

So here is my texture class :

public class Texture
{
   public String Filepath;
   private int TextureID;

   public Texture(byte[] Filename)
   {
        Stream s = FileManager.FindTexture(Filename);

        if (s == null) return;

        Bitmap b = new Bitmap(FileManager.FindTexture(Filename));

        b.MakeTransparent(Color.FromArgb(255,0,255));

        //b = BitmapEx.Resize(b, b.Width * 2, b.Height * 2);

        //b.Save(DateTime.Now.ToFileTimeUtc().ToString() + ".png");
        //GL.Hint(HintTarget.PerspectiveCorrectionHint, HintMode.Nicest);

        GL.GenTextures(1, out TextureID);
        GL.BindTexture(TextureTarget.Texture2D, TextureID);

        BitmapData data = b.LockBits(new Rectangle(0, 0, b.Width, b.Height), ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

        GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba8, data.Width, data.Height, 0, OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, data.Scan0);

        b.UnlockBits(data);

        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.Repeat);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.Repeat);

        if(!GL.IsTexture(TextureID))
        {
            throw new Exception();
        }

    }

    public void Apply()
    {
        if (TextureID != 0)
        {
            GL.BindTexture(TextureTarget.Texture2D, TextureID);
        }
    }
}

As you can see, my bitmap loads well from the stream. I tried to save it after it loaded into a my debug folder and every texture loaded saves. So I'm pretty sure this part is not the problem. But everytime I try to do GL.IsTexture it returns false, I tried to apply my textures either it doesn't work.

I've used a similar method in another project where it was working.

        Bitmap bitmap = new Bitmap("Data/UI/" + File);

        GL.Hint(HintTarget.PerspectiveCorrectionHint, HintMode.Nicest);

        GL.GenTextures(1, out Texture);
        GL.BindTexture(TextureTarget.Texture2D, Texture);

        BitmapData data = bitmap.LockBits(new System.Drawing.Rectangle(0, 0, bitmap.Width, bitmap.Height),
            ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

        GL.TexImage2D(TextureTarget.Texture2D, 0, PixelInternalFormat.Rgba, data.Width, data.Height, 0,
            OpenTK.Graphics.OpenGL.PixelFormat.Bgra, PixelType.UnsignedByte, data.Scan0);
        bitmap.UnlockBits(data);


        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Linear);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Linear);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.Repeat);
        GL.TexParameter(TextureTarget.Texture2D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.Repeat);

I can't see why it is not working right now.

My textures are loaded way after OpenGL is initialized.

I'm using C# .NET framework 3.5 with OpenTK 1.1 ( Runtime 2.0.5, fresh out of their websites ).

Can someone give me a hint on why it is not working, please ?

Warm regards, Chaussette.