VBScript - Passing schtasks command into run method - vbscript

Question

The following .vbs creates the desired task without any issue (please excuse the syntax):
Option Explicit
Dim wshell
Set wshell = CreateObject("WScript.Shell")
wshell.Run "schtasks /create /sc once /tn ""Reminder"" /tr ""C:\Windows\System32\cmd.exe \""/c title Alert & mode con: cols=40 lines=10 & color f0 & cls & echo *** Message goes here *** & echo. & echo. & echo. & echo. & echo. & echo. & echo. & echo Press any key to exit & pause > nul\"""" /st 18:00 /sd 08/20/2016 /f"
However if I try pass the schtasks command string via a variable as follows:
Option explicit
dim strdate, strtime, strmessage, strtask, wshell
strdate = "08/20/2016"
strtime = "18:30"
strmessage = "Turn off pump"
WScript.Echo strdate
WScript.Echo strtime
WScript.Echo strmessage
strtask = """schtasks /create /sc once /tn """"Reminder"""" /tr """"C:\Windows\System32\cmd.exe \""""/c title Alert & mode con: cols=40 lines=10 & color f0 & cls & echo " & strmessage & " & echo. & echo. & echo. & echo. & echo. & echo. & echo. & echo Press any key to exit & pause > nul"""""""" /st " & strtime & " /sd " & strdate & " /f""" & " ,0" & " ,true"
WScript.Echo strtask
Set wshell = CreateObject("WScript.Shell")
wshell.Run strtask
I get the following error:
I can't understand why I'm getting this, the variable being parsed is, after all, identical to the previous snippet (including the quotes)... Could someone please explain to me what I'm missing?
EDIT
Thanks to Ansgar Wiechers' guidance. I've managed to get a working, albeit inelegant, script by removing the run command options, and intrinsically checking for an external command error instead. See hereunder:
option explicit
dim strdate, strtime, strmessage, strtask, exitcode, wshell
strdate = "08/21/2016"
strtime = "13:45"
strmessage = "Turn off pump"
WScript.Echo strdate
WScript.Echo strtime
WScript.Echo strmessage
strtask = "schtasks /create /sc once /tn ""Reminder"" /tr ""C:\Windows\System32\cmd.exe \""/c title Alert & mode con: cols=40 lines=10 & color f0 & cls & echo " & strmessage & " & echo. & echo. & echo. & echo. & echo. & echo. & echo. & echo Press any key to exit & pause > nul\"""" /st " & strtime & " /sd " & strdate & " /f"
set wshell = CreateObject("WScript.Shell")
exitcode = wshell.Run(strtask, 0, True)
if exitcode <> 0
then WScript.Echo "External command failed: " & Hex(exitcode)
End If

Answer 1

I seriously doubt that your original command ever worked. The nested quotes around the argument list to CMD.exe should always have made it raise an error. Remove those nested quotes (leave just the double quotes around the entire CMD statement) and also remove the arguments to the Run method from strTask, and task creation should work as you expect.
strtask = "schtasks /create /sc once /tn ""Reminder""" & _
" /tr ""C:\Windows\System32\cmd.exe /c title Alert" & _
" & mode con: cols=40 lines=10 & color f0 & cls" & _
" & echo " & strmessage & _
" & echo. & echo. & echo. & echo. & echo. & echo. & echo." & _
" & echo Press any key to exit & pause > nul""" & _
" /sd " & strdate & " /st " & strtime & " /f"
exitcode = wshell.Run(strtask, 0, True)
If exitcode <> 0 Then
WScript.Echo "External command failed: " & Hex(exitcode)
End If
It's always a good idea to add some code to check the exit status of external commands, so you can detect if something went wrong.
With that said, you could greatly improve maintainability of this code with some modifications:
Don't create the commandline as one big string. Build it from the inside out.
Use environment variables if possible (e.g. %COMSPEC% instead of the literal path to CMD.exe)
Use quotes only where they're required.
Use a quoting function for adding escaped double quotes.
Function qq(str)
qq = """" & str & """"
End Function
cmdargs = "/c title Alert & mode con: cols=40 lines=10 & color f0 & cls" & _
" & echo " & strmessage & " & echo. & echo. & echo. & echo." & _
" & echo. & echo. & echo. & echo Press any key to exit & pause > nul"
strtask = "schtasks /create /f /sc once /tn Reminder" & _
" /tr " & qq("%COMSPEC% " & cmdargs) & _
" /sd " & strdate & " /st " & strtime
exitcode = wshell.Run(strtask, 0, True)
Better yet, put the batch code into an actual batch file:
#echo off
title Alert
mode con: cols=40 lines=10
color f0
cls
echo %~1
echo.
echo.
echo.
echo.
echo.
echo.
echo.
echo Press any key to exit
pause > nul
and create the task to run that batch file with your message:
Function qq(str)
qq = """" & Replace(str, """", "\""") & """"
End Function
batchfile = "C:\path\to\your.bat"
strtask = "schtasks /create /f /sc once /tn Reminder" & _
" /tr " & qq(qq(batchfile) & " " & qq(strmessage)) & _
" /sd " & strdate & " /st " & strtime
exitcode = wshell.Run(strtask, 0, True)