\nA customer wanted to prevent users from pinning their application\nto the taskbar.\n<\/p>\n
\nI have an application that is launched as a helper by a main application.\nUsers shouldn’t be launching it directly, but rather should be launching\nthe main application.\nBut since the helper shows up in the taskbar,\nusers may be tempted to right-click on the taskbar icon and select\n“Pin to taskbar.”\nUnfortunately, this pins the helper program to the taskbar instead of\nthe main application,\nand launching the helper program directly doesn’t work.\nIs there a way I can prevent users from pinning the helper program?\n<\/p><\/blockquote>\n
\nIt so happens that there are\n\na number of ways of marking your\nhelper program as Don’t pin me<\/i><\/a>.\nGiven the description above, the most direct way is probably to set the\n\n
System.AppUserModel.PreventPinning<\/code>\nproperty<\/a>\non the window created by the helper program.\n<\/p>\n\nTake our\n\nscratch program<\/a>\nand make the following changes:<\/p>\n
\n#include <shellapi.h>\n#include <propsys.h>\n#include <propkey.h>\nHRESULT MarkWindowAsUnpinnable(HWND hwnd)\n{\n IPropertyStore *pps;\n HRESULT hr = SHGetPropertyStoreForWindow(hwnd, IID_PPV_ARGS(&pps));\n if (SUCCEEDED(hr)) {\n PROPVARIANT var;\n var.vt = VT_BOOL;\n var.boolVal = VARIANT_TRUE<\/a>;\n hr = pps->SetValue(PKEY_AppUserModel_PreventPinning, var);\n pps->Release();\n }\n return hr;\n}\n<\/font>\nBOOL\nOnCreate(HWND hwnd, LPCREATESTRUCT lpcs)\n{\n MarkWindowAsUnpinnable(hwnd);<\/font>\n return TRUE;\n}\n<\/pre>\n\nI set the
PROPVARIANT<\/code> manually instead of using\nInitPropVariantFromBoolean<\/code>\njust to emphasize that\n\ntheboolVal<\/code> must beVARIANT_TRUE<\/code> and not\nTRUE<\/code><\/a>.\nIn real life, I probably would have used\nInitPropVariantFromBoolean<\/code>.\n<\/p>\n\nRun this program and observe that “Pin this program\nto taskbar” does not appear on the menu when you\nright-click on the taskbar button.\n<\/p>\n
\nEven better would be to permit pinning,\nbut set the\n\n
System.AppUserModel.RelaunchCommand<\/code><\/a>,\n\n.RelaunchDisplayNameResource<\/code><\/a>\nand optionally\n\n.RelaunchIconResource<\/code><\/a>\nproperties\nso that\n\nif the user tries to pin the helper,\nit actually pins the main application<\/a>.\n<\/p>\n\nStart with a new scratch program and make these changes:\n<\/p>\n
\n#include <shellapi.h>\n#include <propsys.h>\n#include <propkey.h>\n#include <propvarutil.h>\nHRESULT IPropertyStore_SetValue(IPropertyStore *pps,\n REFPROPERTYKEY pkey, PCWSTR pszValue)\n{\n PROPVARIANT var;\n HRESULT hr = InitPropVariantFromString(pszValue, &var);\n if (SUCCEEDED(hr))\n {\n hr = pps->SetValue(pkey, var);\n PropVariantClear(&var);\n }\n return hr;\n}<\/font>\nBOOL\nOnCreate(HWND hwnd, LPCREATESTRUCT lpcs)\n{\n IPropertyStore *pps;\n HRESULT hr = SHGetPropertyStoreForWindow(hwnd, IID_PPV_ARGS(&pps));\n if (SUCCEEDED(hr)) {\n IPropertyStore_SetValue(pps,\n PKEY_AppUserModel_ID, L\"Contoso.Scratch\");\n IPropertyStore_SetValue(pps,\n PKEY_AppUserModel_RelaunchCommand,\n L\"notepad.exe %windir%\\\\system.ini\");\n IPropertyStore_SetValue(pps,\n PKEY_AppUserModel_RelaunchDisplayNameResource,\n L\"C:\\\\full\\\\path\\\\to\\\\scratch.exe,-1\");\n \/\/ optionally also set PKEY_AppUserModel_RelaunchIconResource\n pps->Release();\n }<\/font>\n return TRUE;\n}\n\/\/ resource file\nSTRINGTABLE BEGIN\n 1 \"Open system.ini\"\nEND\n<\/pre>\n\nI’m pulling a fast one here and pretending that Notepad is my\nmain application.\nObviously you’d use your actual main application.\n(I’m also hard-coding the path to my scratch program.)\n<\/p>\n
\nWhen you run this program, right-click on the taskbar button.\nObserve that the option to run a new copy of the program is called\nOpen system.ini<\/i> and if you pick it\n(or use the middle-mouse-button shortcut),\nNotepad runs.\nIf you pin the program, the pinned icon runs Notepad.\n<\/p>\n