Question

I wish to write a small tool that will capture a global event when the user presses the Windows button and scrolls the mousewheel up or down. When such an event is captured, I wish to redirect said output to a virtual keystroke combination of Win-+ or Win– (plus/minus). Can this be done?

If the windows key is reserved, ctrl-alt or such would do.

Answer 1

Since it uses the windows key, the key can be captured globally using a hotkey binding. RegisterHotKey at msdn.

Edit: It seems the mousewheel events are not treated as keys as I assumed and there is no way to make a global hotkey for them.

You will have to make a global window message hook and trap the WM_MOUSEWHEEL message. But you may have to do that in C/C++. A C dll to accomplish this is below, you can call Hook and Unhook from C# to enable and disable the function.

WARNING: I have not tested this code and is provided as a demonstration only.

#include <windows.h>  HINSTANCE myInstance; HHOOK thehook = 0; BOOL isWinKeyDown = FALSE;  extern 'C' LRESULT __declspec(dllexport)__stdcall CALLBACK HookHandler(int nCode, WPARAM wParam, LPARAM lParam) {     if (nCode == WM_KEYDOWN && (wParam == VK_LWIN || wParam == VK_RWIN))         isWinKeyDown = TRUE;     else if (nCode == WM_KEYUP && (wParam == VK_LWIN || wParam == VK_RWIN))         isWinKeyDown = FALSE;     else if (nCode == WM_MOUSEHWHEEL && isWinKeyDown) {         if (HIWORD(wParam) > 0) { //mousewheel up             CallNextHookEx(thehook, WM_KEYDOWN, VK_ADD, 0);             CallNextHookEx(thehook, WM_KEYUP, VK_ADD, 0);         } else { //mousewheel down             CallNextHookEx(thehook, WM_KEYDOWN, VK_SUBTRACT, 0);             CallNextHookEx(thehook, WM_KEYUP, VK_SUBTRACT, 0);         }         return 0;     }     return CallNextHookEx(thehook, nCode, wParam, lParam); } BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD fwdReason, LPVOID lpvReserved) {     switch(fwdReason)     {         case DLL_PROCESS_ATTACH: {             DisableThreadLibraryCalls(hInstance);             myInstance = hInstance;              } break;         case DLL_THREAD_ATTACH:             break;         case DLL_PROCESS_DETACH:              break;         case DLL_THREAD_DETACH:             break;     }     return(TRUE);               // The initialization was successful, a FALSE will abort                                 // the DLL attach }  extern 'C' void __declspec(dllexport) Hook() {     if (!thehook)         thehook = SetWindowsHookEx(WH_CALLWNDPROC, &HookHandler, myInstance, 0); } extern 'C' void __declspec(dllexport) UnHook() {     if (thehook)         UnhookWindowsHookEx(thehook);     thehook = 0; }