Running a form on a Windows C # login screen

Question

I need to write a small tool that runs on every userdesktop or, if no one is logged in, directly on the login screen. Maybe the service with the form begins?

I already found this question (and the answer): Starting the process on the Windows 7 welcome screen

// grab the winlogon process Process winLogon = null; foreach (Process p in Process.GetProcesses()) { if (p.ProcessName.Contains("winlogon")) { winLogon = p; break; } } // grab the winlogon token IntPtr userToken = IntPtr.Zero; if (!OpenProcessToken(winLogon.Handle, TOKEN_QUERY | TOKEN_IMPERSONATE | TOKEN_DUPLICATE, out userToken)) { log("ERROR: OpenProcessToken returned false - " + Marshal.GetLastWin32Error()); } // create a new token IntPtr newToken = IntPtr.Zero; SECURITY_ATTRIBUTES tokenAttributes = new SECURITY_ATTRIBUTES(); tokenAttributes.nLength = Marshal.SizeOf(tokenAttributes); SECURITY_ATTRIBUTES threadAttributes = new SECURITY_ATTRIBUTES(); threadAttributes.nLength = Marshal.SizeOf(threadAttributes); // duplicate the winlogon token to the new token if (!DuplicateTokenEx(userToken, 0x10000000, ref tokenAttributes, SECURITY_IMPERSONATION_LEVEL.SecurityImpersonation, TOKEN_TYPE.TokenImpersonation, out newToken)) { log("ERROR: DuplicateTokenEx returned false - " + Marshal.GetLastWin32Error()); } TOKEN_PRIVILEGES tokPrivs = new TOKEN_PRIVILEGES(); tokPrivs.PrivilegeCount = 1; LUID seDebugNameValue = new LUID(); if (!LookupPrivilegeValue(null, SE_DEBUG_NAME, out seDebugNameValue)) { log("ERROR: LookupPrivilegeValue returned false - " + Marshal.GetLastWin32Error()); } tokPrivs.Privileges = new LUID_AND_ATTRIBUTES[1]; tokPrivs.Privileges[0].Luid = seDebugNameValue; tokPrivs.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED; // escalate the new token privileges if (!AdjustTokenPrivileges(newToken, false, ref tokPrivs, 0, IntPtr.Zero, IntPtr.Zero)) { log("ERROR: AdjustTokenPrivileges returned false - " + Marshal.GetLastWin32Error()); } PROCESS_INFORMATION pi = new PROCESS_INFORMATION(); STARTUPINFO si = new STARTUPINFO(); si.cb = Marshal.SizeOf(si); si.lpDesktop = "Winsta0\\Winlogon"; // start the process using the new token if (!CreateProcessAsUser(newToken, process, process, ref tokenAttributes, ref threadAttributes, true, (uint)CreateProcessFlags.CREATE_NEW_CONSOLE | (uint)CreateProcessFlags.INHERIT_CALLER_PRIORITY, IntPtr.Zero, logInfoDir, ref si, out pi)) { log("ERROR: CreateProcessAsUser returned false - " + Marshal.GetLastWin32Error()); } Process _p = Process.GetProcessById(pi.dwProcessId); if (_p != null) { log("Process " + _p.Id + " Name " + _p.ProcessName); } else { log("Process not found"); } 

But no DLL import is explained, so I can’t build it.

Thank you for your efforts Fluxer