I can't understand how to use SendMessage or PostMessage calls

Question

I need to simulate a keypress in a third party application. Let\'s say I have a C# application that needs to send an \"8\" to the Calculator application. I can\'t use the Se

Answer 1

Because it is an Edit Child window inside the notepad window. You should send messages to the right child window. It is a working example in C:

#include 
#include 

void main(void) {
    STARTUPINFO si;
    PROCESS_INFORMATION pi;
    HWND mainwnd,editwnd;
    char c;
    si.cb=sizeof(si);
    si.lpReserved=NULL;
    si.lpDesktop=NULL;
    si.lpTitle=NULL;
    si.dwFlags=0;
    si.cbReserved2=0;
    si.lpReserved2=NULL;
    if(!CreateProcess("c:\\windows\\notepad.exe",NULL,NULL,NULL,FALSE,0,NULL,NULL,&si,&pi)) {
        printf("Failed to run app");
        return;
    }
    WaitForInputIdle(pi.hProcess,INFINITE);
    mainwnd=FindWindow(NULL,"Untitled - Notepad");
    if(!mainwnd) {
        printf("Main window not found");
        return;
    }
    editwnd=FindWindowEx(mainwnd,NULL,"Edit","");
    if(!editwnd) {
        printf("Edit window not found");
        return;
    }
    for(c='1';c<='9';c++) {
        PostMessage(editwnd,WM_CHAR,c,1);
        Sleep(100);
    }
}