How to refresh/reload Desktop
I have a WPF C# project in which I'm implementing settings for Windows folder options. One of them is "Single-click to open an item" (instead of double-click). When I change the registry keys for that matter, I need to refresh Windows Explorer which I found a solution for. But desktop doesn't refresh, and even refreshing it manually doesn't apply the changes. I've used IActiveDesktop::ApplyChanges Method but didn't work (or maybe I made a mistake). I've also used this code snippet, but it still doesn't apply the changes I've made:
SHChangeNotify(0x8000000, 0x1000, IntPtr.Zero, IntPtr.Zero);
And here is the full code snippet that I used for refreshing Win Explorer(witch is from this site):
[System.Runtime.InteropServices.DllImport("Shell32.dll")]
private static extern int SHChangeNotify(int eventId, int flags, IntPtr item1, IntPtr item2);
public static void RefreshWindowsExplorer()
{
// Refresh the desktop
SHChangeNotify(0x8000000, 0x1000, IntPtr.Zero, IntPtr.Zero);
// Refresh any open explorer windows
// based on http://stackoverflow.com/questions/2488727/refresh-windows-explorer-in-win7
Guid CLSID_ShellApplication = new Guid("13709620-C279-11CE-A49E-444553540000");
Type shellApplicationType = Type.GetTypeFromCLSID(CLSID_ShellApplication, true);
object shellApplication = Activator.CreateInstance(shellApplicationType);
object windows = shellApplicationType.InvokeMember("Windows", System.Reflection.BindingFlags.InvokeMethod, null, shellApplication, new object[] { });
Type windowsType = windows.GetType();
object count = windowsType.InvokeMember("Count", System.Reflection.BindingFlags.GetProperty, null, windows, null);
for (int i = 0; i < (int)count; i++)
{
object item = windowsType.InvokeMember("Item", System.Reflection.BindingFlags.InvokeMethod, null, windows, new object[] { i });
Type itemType = item.GetType();
// Only refresh Windows Explorer, without checking for the name this could refresh open IE windows
string itemName = (string)itemType.InvokeMember("Name", System.Reflection.BindingFlags.GetProperty, null, item, null);
if (itemName == "Windows Explorer")
{
itemType.InvokeMember("Refresh", System.Reflection.BindingFlags.InvokeMethod, null, item, null);
}
}
}
That works for Windows Explorer but not the desktop (which is odd since desktop depends on explorer too). So how should I reload the desktop so that my changes take effect?
If you would have posted the code to change that setting, I would have tested it against the following suggestions before replying.
Have you tried:
1) Removing the statement if (itemName == "Windows Explorer") from the above code, so it refreshes every window (including the desktop)?
2) Broadcasting a WM_SETTINGCHANGE via SendMessage WIN32 API?
private const int HWND_BROADCAST = 0xffff;
private const int WM_WININICHANGE = 0x001a, WM_SETTINGCHANGE = 0x001a, INI_INTL = 1;
[DllImport("user32.dll")]
private static extern int SendMessage(int hWnd, uint wMsg, uint wParam, uint lParam);
SendMessage(HWND_BROADCAST, WM_SETTINGCHANGE, 0, INI_INTL);
[Credit]
3) IActiveDesktop.ApplyChanges
[ComImport]
[Guid("F490EB00-1240-11D1-9888-006097DEACF9")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IActiveDesktop
{
[PreserveSig]
int ApplyChanges(AD_Apply dwFlags);
// [...]
// Note: There is a lot more to this interface,
// please see PInvoke.net link below.
}
private const int AD_APPLY_REFRESH = 4;
IActiveDesktop.ApplyChanges(AD_APPLY_REFRESH);
[PInvoke.net - IActiveDesktop]
If these do not work, let me know. If it comes down to it, it is possible to save all the open explorer windows & their positions, terminate explorer, wait for explorer to restart, re-open each explorer window and re-position them... if that would acceptable.
Hope this helps.
Thanks for all your replies and comments. I finally figured out a workaround for this problem. We could just hide all desktop icons and then show them again. This will force the desktop to reload.
Update: In Window 8, SHELLDLL_DefView is the child of one of WorkerW windows. (instead of Progman ) So here is the updated code which works on Windows 8 and 8.1 too:
[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);
[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr GetWindow(IntPtr hWnd, GetWindow_Cmd uCmd);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);
enum GetWindow_Cmd : uint
{
GW_HWNDFIRST = 0,
GW_HWNDLAST = 1,
GW_HWNDNEXT = 2,
GW_HWNDPREV = 3,
GW_OWNER = 4,
GW_CHILD = 5,
GW_ENABLEDPOPUP = 6
}
private const int WM_COMMAND = 0x111;
[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);
private delegate bool EnumWindowsProc(IntPtr hWnd, IntPtr lParam);
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
private static extern int GetWindowText(IntPtr hWnd, StringBuilder strText, int maxCount);
[DllImport("user32.dll", CharSet = CharSet.Unicode)]
private static extern int GetWindowTextLength(IntPtr hWnd);
[DllImport("user32.dll")]
private static extern bool EnumWindows(EnumWindowsProc enumProc, IntPtr lParam);
[DllImport("user32.dll", SetLastError = true, CharSet = CharSet.Auto)]
static extern int GetClassName(IntPtr hWnd, StringBuilder lpClassName, int nMaxCount);
public static string GetWindowText(IntPtr hWnd)
{
int size = GetWindowTextLength(hWnd);
if (size++ > 0)
{
var builder = new StringBuilder(size);
GetWindowText(hWnd, builder, builder.Capacity);
return builder.ToString();
}
return String.Empty;
}
public static IEnumerable<IntPtr> FindWindowsWithClass(string className)
{
IntPtr found = IntPtr.Zero;
List<IntPtr> windows = new List<IntPtr>();
EnumWindows(delegate(IntPtr wnd, IntPtr param)
{
StringBuilder cl = new StringBuilder(256);
GetClassName(wnd, cl, cl.Capacity);
if (cl.ToString() == className && (GetWindowText(wnd) == "" || GetWindowText(wnd) == null))
{
windows.Add(wnd);
}
return true;
},
IntPtr.Zero);
return windows;
}
static void ToggleDesktopIcons()
{
var toggleDesktopCommand = new IntPtr(0x7402);
IntPtr hWnd = IntPtr.Zero;
if (Environment.OSVersion.Version.Major < 6 || Environment.OSVersion.Version.Minor < 2) //7 and -
hWnd = GetWindow(FindWindow("Progman", "Program Manager"), GetWindow_Cmd.GW_CHILD);
else
{
var ptrs = FindWindowsWithClass("WorkerW");
int i = 0;
while (hWnd == IntPtr.Zero && i < ptrs.Count())
{
hWnd = FindWindowEx(ptrs.ElementAt(i), IntPtr.Zero, "SHELLDLL_DefView", null);
i++;
}
}
SendMessage(hWnd, WM_COMMAND, toggleDesktopCommand, IntPtr.Zero);
}
Now we can just toggle desktop icons twice:
ToggleDesktopIcons();
ToggleDesktopIcons();
Hope this helps someone else ...
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