Here is a new type of Form, a ProgressForm that adds progressbar-like properties to a standard System.Windows.Form. Simply use the ProgressForm in place of standard Form and set Value to 50 (Maximum defaults to 100 and Minimum is a non-settable value of 0) and set State to ThumbnailProgressState.Normal. If the OS is older than Windows 7, this class simply does nothing to the taskbar, keeping the application backwards compatible. This code also will keep the progress indication in the taskbar if explorer restarts for some unknown reason.
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
}
}
