Programming Forums > Application Development > C#

Pedja · Mar 22nd, 2006, 3:34 PM

Hi there.
I have a problem. When I change the default icon for some file extension, I need it to happen instantly. For example, I want to change icon for .cdc files. I know how to do it, and that is not a problem, but the problem is that it doesn't happen instantly, but when some kind of system refresh happens. I think it has something to do with shelliconcache.dll or iconcache.db, witch i can't find on my system. I have WXP Professional.
For example, when you start BS Player and assign it to be the default player for some file types, it happens, and all icons change right away.
I need to know what I can do to make this change happening when I want it. What is the thing that BS player and Windows Media Player do when they make a registry change, to make it happen at that exact moment?
The thing is that i am creating an application that should be able to do this, and i have no idea what should be done, and how BS Player does it.
Maybe I need to send some kind of system message to tell the OS to reload icon cache.
Any help would be most appreciated.
Thanks.

The Dark · Mar 22nd, 2006, 6:26 PM

Google is your friend

Dameon · Mar 22nd, 2006, 9:14 PM

@The Dark: I'd have to say, that link is far from useful.

I haven't been able to find a good answer. Odd.

nnxion · Mar 23rd, 2006, 3:17 AM

I know that the tweakUI powertool rebuilds your icons just for that purpose.
I think you need to do the same.

The Dark · Mar 23rd, 2006, 5:15 AM

@Dameon: Really? The first link off google (the codeproject one) shows a similar problem with changing the icons and shows the exact call needed to get the icon cache to be refreshed.

(Toggle Plain Text)

 ::SendMessage(HWND_BROADCAST ,
        WM_SETTINGCHANGE,SPI_SETNONCLIENTMETRICS,NULL);

I suspect that there is a better SPI_ value for icon changing, but this one (suposedly) does the trick.

Pedja · Mar 24th, 2006, 3:19 PM

Guys, thank you all for helping, especially The Dark (again).
You got it right, but i still have a problem.
ShellIconChanger really works, and it does what my app needs to do, but i have problems implementing the same in C#.

Here is what happens:

(Toggle Plain Text)

[DllImport("user32.dll")]
        public static extern uint SendMessage(IntPtr hWnd, uint Msg, uint wParam, IntPtr lParam);

(Toggle Plain Text)

RegistryKey k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true);
k.SetValue("Shell Icon Size", "33");  //this value in my reg is 32
k.Flush(); k.Close();

SendMessage((IntPtr)0xffff, 0x001A, 0x002A, IntPtr.Zero);

k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true);
k.SetValue("Shell Icon Size", "32");  //back to what it was
k.Flush(); k.Close();

SendMessage((IntPtr)0xffff, 0x001A, 0x002A, IntPtr.Zero);

App always blocks on second call to SendMessage function.
Icons sometimes change immediately, and sometimes don't.
From my app, icons change immediately only when I start it after doing the same thing in ShellIconChanger. Every other time app fails to do this.
What am I missing?

The Dark · Mar 24th, 2006, 6:23 PM

It may be the fault of another program you are running. If an app doesn't respond to the global SendMessage, it sits there waiting for it for a period of time. I am not sure what you can do about it though.

Dameon · Mar 24th, 2006, 7:58 PM

Use PostMessage instead?

Sorry about the criticism of the link. I seem to have missed the first result...somehow.

Pedja · Mar 25th, 2006, 8:03 AM

It works! The SendMessageTimeout function does the trick.

(Toggle Plain Text)

private static extern long SendMessageTimeout(
	int hWnd,
	int Msg,
	int wParam,
	string lParam,
	int fuFlags,
	int uTimeout,
	out int lpdwResult
);

(Toggle Plain Text)

RegistryKey k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true);
k.SetValue("Shell Icon Size", "33");
k.Flush(); k.Close();

int res = 0;
SendMessageTimeout(0xffff, 0x001A, 0, "", 0x0002, 5000, out res);

k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true);
k.SetValue("Shell Icon Size", "32");
k.Flush(); k.Close();

SendMessageTimeout(0xffff, 0x001A, 0, "", 0x0002, 5000, out res);

This function specifies the timeout period. After 5 seconds (in this case) program returns from the function, and icons are reloaded.
I still don't understand why the program never returned from SendMessage function, but it's not so important.
Thanks a lot.

Mar 22nd, 2006, 3:34 PM	#1
Pedja Programmer Join Date: Nov 2005 Location: Belgrade, Serbia & Montenegro Posts: 31 Rep Power: 0	Changing icons problem Hi there. I have a problem. When I change the default icon for some file extension, I need it to happen instantly. For example, I want to change icon for .cdc files. I know how to do it, and that is not a problem, but the problem is that it doesn't happen instantly, but when some kind of system refresh happens. I think it has something to do with shelliconcache.dll or iconcache.db, witch i can't find on my system. I have WXP Professional. For example, when you start BS Player and assign it to be the default player for some file types, it happens, and all icons change right away. I need to know what I can do to make this change happening when I want it. What is the thing that BS player and Windows Media Player do when they make a registry change, to make it happen at that exact moment? The thing is that i am creating an application that should be able to do this, and i have no idea what should be done, and how BS Player does it. Maybe I need to send some kind of system message to tell the OS to reload icon cache. Any help would be most appreciated. Thanks.

Mar 22nd, 2006, 9:14 PM	#3
Dameon Troll Join Date: Apr 2005 Location: Texas Posts: 732 Rep Power: 4	@The Dark: I'd have to say, that link is far from useful. I haven't been able to find a good answer. Odd. __________________ MD5(sig) = bcef75433db02e9ad9bf81d6f7c5c270

Mar 23rd, 2006, 3:17 AM	#4
nnxion Programming Guru Join Date: Jun 2005 Location: elemental plane Posts: 1,429 Rep Power: 5	I know that the tweakUI powertool rebuilds your icons just for that purpose. I think you need to do the same. __________________ "Employ your time in improving yourself by other men's writings, so that you shall gain easily what others have labored hard for." -- Socrates

Mar 23rd, 2006, 5:15 AM	#5
The Dark Expert Programmer Join Date: Jun 2005 Posts: 825 Rep Power: 4	@Dameon: Really? The first link off google (the codeproject one) shows a similar problem with changing the icons and shows the exact call needed to get the icon cache to be refreshed. (Toggle Plain Text) ::SendMessage(HWND_BROADCAST , WM_SETTINGCHANGE,SPI_SETNONCLIENTMETRICS,NULL); ::SendMessage(HWND_BROADCAST , WM_SETTINGCHANGE,SPI_SETNONCLIENTMETRICS,NULL); I suspect that there is a better SPI_ value for icon changing, but this one (suposedly) does the trick.

Mar 24th, 2006, 3:19 PM	#6
Pedja Programmer Join Date: Nov 2005 Location: Belgrade, Serbia & Montenegro Posts: 31 Rep Power: 0	Guys, thank you all for helping, especially The Dark (again). You got it right, but i still have a problem. ShellIconChanger really works, and it does what my app needs to do, but i have problems implementing the same in C#. Here is what happens: (Toggle Plain Text) [DllImport("user32.dll")] public static extern uint SendMessage(IntPtr hWnd, uint Msg, uint wParam, IntPtr lParam); [DllImport("user32.dll")] public static extern uint SendMessage(IntPtr hWnd, uint Msg, uint wParam, IntPtr lParam); (Toggle Plain Text) RegistryKey k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true); k.SetValue("Shell Icon Size", "33"); //this value in my reg is 32 k.Flush(); k.Close(); SendMessage((IntPtr)0xffff, 0x001A, 0x002A, IntPtr.Zero); k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true); k.SetValue("Shell Icon Size", "32"); //back to what it was k.Flush(); k.Close(); SendMessage((IntPtr)0xffff, 0x001A, 0x002A, IntPtr.Zero); RegistryKey k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true); k.SetValue("Shell Icon Size", "33"); //this value in my reg is 32 k.Flush(); k.Close(); SendMessage((IntPtr)0xffff, 0x001A, 0x002A, IntPtr.Zero); k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true); k.SetValue("Shell Icon Size", "32"); //back to what it was k.Flush(); k.Close(); SendMessage((IntPtr)0xffff, 0x001A, 0x002A, IntPtr.Zero); App always blocks on second call to SendMessage function. Icons sometimes change immediately, and sometimes don't. From my app, icons change immediately only when I start it after doing the same thing in ShellIconChanger. Every other time app fails to do this. What am I missing?

Mar 22nd, 2006, 6:26 PM	#2
The Dark Expert Programmer Join Date: Jun 2005 Posts: 825 Rep Power: 4	Google is your friend

Mar 24th, 2006, 6:23 PM	#7
The Dark Expert Programmer Join Date: Jun 2005 Posts: 825 Rep Power: 4	It may be the fault of another program you are running. If an app doesn't respond to the global SendMessage, it sits there waiting for it for a period of time. I am not sure what you can do about it though.

Mar 24th, 2006, 7:58 PM	#8
Dameon Troll Join Date: Apr 2005 Location: Texas Posts: 732 Rep Power: 4	Use PostMessage instead? Sorry about the criticism of the link. I seem to have missed the first result...somehow. __________________ MD5(sig) = bcef75433db02e9ad9bf81d6f7c5c270

Mar 25th, 2006, 8:03 AM	#9
Pedja Programmer Join Date: Nov 2005 Location: Belgrade, Serbia & Montenegro Posts: 31 Rep Power: 0	It works! The SendMessageTimeout function does the trick. (Toggle Plain Text) private static extern long SendMessageTimeout( int hWnd, int Msg, int wParam, string lParam, int fuFlags, int uTimeout, out int lpdwResult ); private static extern long SendMessageTimeout( int hWnd, int Msg, int wParam, string lParam, int fuFlags, int uTimeout, out int lpdwResult ); (Toggle Plain Text) RegistryKey k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true); k.SetValue("Shell Icon Size", "33"); k.Flush(); k.Close(); int res = 0; SendMessageTimeout(0xffff, 0x001A, 0, "", 0x0002, 5000, out res); k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true); k.SetValue("Shell Icon Size", "32"); k.Flush(); k.Close(); SendMessageTimeout(0xffff, 0x001A, 0, "", 0x0002, 5000, out res); RegistryKey k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true); k.SetValue("Shell Icon Size", "33"); k.Flush(); k.Close(); int res = 0; SendMessageTimeout(0xffff, 0x001A, 0, "", 0x0002, 5000, out res); k = Registry.CurrentUser.OpenSubKey("Control Panel").OpenSubKey("Desktop").OpenSubKey("WindowMetrics", true); k.SetValue("Shell Icon Size", "32"); k.Flush(); k.Close(); SendMessageTimeout(0xffff, 0x001A, 0, "", 0x0002, 5000, out res); This function specifies the timeout period. After 5 seconds (in this case) program returns from the function, and icons are reloaded. I still don't understand why the program never returned from SendMessage function, but it's not so important. Thanks a lot.

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Programming Forums > Application Development > C#

Changing icons problem