TaskbarProgressHelper.cs

using System;
using System.Runtime.InteropServices;

namespace bookGrabber {
  
  internal static class TaskbarProgressHelper {

    public enum TaskbarStates {
      NoProgress = 0,
      Indeterminate = 0x1,
      Normal = 0x2,
      Error = 0x4,
      Paused = 0x8
    }

    [ComImport]
    [Guid("ea1afb91-9e28-4b86-90e9-9e9f8a5eefaf")]
    [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
    private interface ITaskbarList3 {
      [PreserveSig]
      void HrInit();

      [PreserveSig]
      void AddTab(IntPtr hwnd);

      [PreserveSig]
      void DeleteTab(IntPtr hwnd);

      [PreserveSig]
      void ActivateTab(IntPtr hwnd);

      [PreserveSig]
      void SetActiveAlt(IntPtr hwnd);

      // ITaskbarList2
      [PreserveSig]
      void MarkFullscreenWindow(IntPtr hwnd, [MarshalAs(UnmanagedType.Bool)] bool fFullscreen);

      // ITaskbarList3
      [PreserveSig]
      void SetProgressValue(IntPtr hwnd, ulong ullCompleted, ulong ullTotal);

      [PreserveSig]
      void SetProgressState(IntPtr hwnd, TaskbarStates state);
    }

    [ComImport]
    [Guid("56fdf344-fd6d-11d0-958a-006097c9a090")]
    [ClassInterface(ClassInterfaceType.None)]
    private class TaskbarInstance  {
    }

    [DllImport("kernel32.dll")]
    static extern IntPtr GetConsoleWindow();

    private static readonly ITaskbarList3 taskbarInstance = (ITaskbarList3) new TaskbarInstance();
    private static readonly bool taskbarSupported = Environment.OSVersion.Version >= new Version(6, 1);
    private static IntPtr handle = IntPtr.Zero;

    private static IntPtr Handle {
      get {
        if (handle == IntPtr.Zero) {
          //handle = Process.GetCurrentProcess().MainWindowHandle;
          handle = GetConsoleWindow();
        }
        return handle;
      }
    }

    public static void SetState(TaskbarStates taskbarState) {
      if (taskbarSupported)
        taskbarInstance.SetProgressState(Handle, taskbarState);
    }

    public static void SetValue(double progressValue, double progressMax) {
      if (taskbarSupported)
        taskbarInstance.SetProgressValue(Handle, (ulong) progressValue, (ulong) progressMax);
    }
  }
}