如何在 C# 窗口应用程序中的任务栏图标上显示操作的进度

这是一种新类型的窗体，一种将类似进度条的属性添加到标准 System.Windows.Form 的 ProgressForm。只需使用 ProgressForm 代替标准窗体，并将 Value 设置为 50（最大值默认值为 100，最小值是不可设置的值 0），并将"状态"设置为"缩略图进度状态.Normal"。如果操作系统早于 Windows 7，则此类不会对任务栏执行任何操作，从而使应用程序向后兼容。如果资源管理器由于某种未知原因重新启动，此代码还将在任务栏中保留进度指示。

using System.ComponentModel;
using System.Drawing;
using System.Runtime.InteropServices;
namespace System.Windows.Forms
{
  [ToolboxBitmap(typeof(Form))]
  public class ProgressForm : Form
  {
    private ThumbnailProgressState m_State = ThumbnailProgressState.NoProgress;
    private int m_Maximum = 100;
    private int m_Value = 0;
    //
    // Summary:
    //     Gets or sets the state in which progress should be indicated on the task
    //     bar.
    //
    // Returns:
    //     One of the System.Windows.Forms.ThumbnailProgressState values. The default is System.Windows.Forms.ThumbnailProgressState.NoProgress
    //
    // Exceptions:
    //   T:System.ComponentModel.InvalidEnumArgumentException:
    //     The value is not a member of the System.Windows.Forms.ThumbnailProgressState enumeration.
    [Browsable(true)]
    [DefaultValue(ThumbnailProgressState.NoProgress)]
    [EditorBrowsable(EditorBrowsableState.Always)]
    public ThumbnailProgressState State
    {
      get { return m_State; }
      set
      {
        switch (value)
        {
          case ThumbnailProgressState.NoProgress:
          case ThumbnailProgressState.Indeterminate:
          case ThumbnailProgressState.Normal:
          case ThumbnailProgressState.Error:
          case ThumbnailProgressState.Paused:
            m_State = value;
            OnStateChanged(new EventArgs());
            break;
          default:
            throw new InvalidEnumArgumentException("The value is not a member of the System.Windows.Forms.ThumbnailProgressState enumeration.");
        }
      }
    }
    //
    // Summary:
    //     Gets or sets the current position of the progress bar.
    //
    // Returns:
    //     The position within the range of the progress bar. The default is 0.
    //
    // Exceptions:
    //   T:System.ArgumentException:
    //     The value specified is greater than the value of the System.Windows.Forms.ProgressForm.Maximum
    //     property. -or- The value specified is less than 0.
    [Browsable(true)]
    [DefaultValue(0)]
    [EditorBrowsable(EditorBrowsableState.Always)]
    public int Value
    {
      get { return m_Value; }
      set
      {
        if ((value < 0) || (value > m_Maximum))
        {
          throw new ArgumentException("The value specified is greater than the value of the System.Windows.Forms.ProgressForm.Maximum property. -or- The value specified is less than 0.");
        }
        else
        {
          m_Value = value;
          OnValueChanged(new EventArgs());
        }
      }
    }
    //
    // Summary:
    //     Gets or sets the maximum value of the range of the control.
    //
    // Returns:
    //     The maximum value of the range. The default is 100.
    //
    // Exceptions:
    //   T:System.ArgumentException:
    //     The value specified is less than 0.
    [Browsable(true)]
    [DefaultValue(100)]
    [EditorBrowsable(EditorBrowsableState.Always)]
    public int Maximum
    {
      get { return m_Maximum; }
      set
      {
        if (value < 0) 
        {
          throw new ArgumentException("The value specified is less than 0.");
        }
        else
        {
          m_Maximum = value;
          if (value < m_Value) m_Value = value;
          OnMaximumChanged(new EventArgs());
        }
      }
    }
    protected virtual void OnStateChanged(EventArgs e)
    {
      if (Windows7orGreater) SetProgressState();
    }
    protected virtual void OnValueChanged(EventArgs e)
    {
      if (Windows7orGreater) SetProgressValue();
    }
    protected virtual void OnMaximumChanged(EventArgs e)
    {
      if (Windows7orGreater) SetProgressValue();
    }
    protected override void WndProc(ref Message m)
    {
      if (Windows7orGreater)
      {
        // if taskbar button created or recreated, update progress status
        if (m.Msg == WM_TaskbarButtonCreated) SetProgressState();
      }
      base.WndProc(ref m);
    }
    private void SetProgressState()
    {
      // must be Windows7orGreater
      TaskbarList.SetProgressState(Handle, m_State);
      SetProgressValue();
    }
    private void SetProgressValue()
    {
      // must be Windows7orGreater
      switch (m_State)
      {
        case ThumbnailProgressState.Normal:
        case ThumbnailProgressState.Error:
        case ThumbnailProgressState.Paused:
          TaskbarList.SetProgressValue(Handle, (ulong)m_Value, (ulong)m_Maximum);
          break;
      }
    }
    private static int WM_TaskbarButtonCreated = -1;
    private static int _winVersion = -1;
    internal static bool Windows7orGreater
    {
      get
      {
        if (_winVersion < 0)
        {
          Version osVersion = Environment.OSVersion.Version;
          if ((osVersion.Major == 6 && osVersion.Minor > 0) || (osVersion.Major > 6))
          {
            // Taskbar progress indicator requires Windows 7 Or Greater
            _winVersion = 1;
            // register taskbar creation window message
            WM_TaskbarButtonCreated = RegisterWindowMessage(@"TaskbarButtonCreated");
          }
          else
          {
            _winVersion = 0;
          }
        }
        return (_winVersion > 0);
      }
    }
    private static ITaskbarList3 _taskbarList = null;
    internal static ITaskbarList3 TaskbarList
    {
      get
      {
        if (_taskbarList == null)
        {
          lock (typeof(ProgressForm))
          {
            if (_taskbarList == null)
            {
              _taskbarList = (ITaskbarList3)new CTaskbarList();
              _taskbarList.HrInit();
            }
          }
        }
        return _taskbarList;
      }
    }
    [DllImport("user32.dll")]
    internal static extern int RegisterWindowMessage(string message);
    [ComImportAttribute()]
    [GuidAttribute("ea1afb91-9e28-4b86-90e9-9e9f8a5eefaf")]
    [InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
    internal interface ITaskbarList3
    {
      // ITaskbarList
      [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
      void SetProgressValue(IntPtr hwnd, UInt64 ullCompleted, UInt64 ullTotal);
      void SetProgressState(IntPtr hwnd, ThumbnailProgressState tbpFlags);
    }
    [GuidAttribute("56FDF344-FD6D-11d0-958A-006097C9A090")]
    [ClassInterfaceAttribute(ClassInterfaceType.None)]
    [ComImportAttribute()]
    internal class CTaskbarList { }
  }
  public enum ThumbnailProgressState
  {
    /// <summary>
    /// No progress is displayed.
    /// </summary>
    NoProgress = 0,
    /// <summary>
    /// The progress is indeterminate (marquee).
    /// </summary>
    Indeterminate = 0x1,
    /// <summary>
    /// Normal progress is displayed.
    /// </summary>
    Normal = 0x2,
    /// <summary>
    /// An error occurred (red).
    /// </summary>
    Error = 0x4,
    /// <summary>
    /// The operation is paused (yellow).
    /// </summary>
    Paused = 0x8
  }
}