Private Declare Function OpenProcess Lib "kernel32" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Private Declare Function GetExitCodeProcess Lib "kernel32" (ByVal hProcess As Long, lpExitCode As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Const PROCESS_QUERY_INFORMATION = &H400
Const STILL_ALIVE = &H103
Private Sub Command1_Click()
Dim pid As Long
pid = Shell("c:/a.bat", vbNormalFocus)
hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, 0, pid)
Do
Call GetExitCodeProcess(hProcess, ExitCode)
DoEvents()
Loop While ExitCode = STILL_ALIVE
Call CloseHandle(hProcess)
MsgBox("運作結束")
End Sub
VB啟動/結束另一程式(Shell 等待程式運作結束)
VB 中,常以Shell指令來執行外部程式,然而它在Create該外部process 後,立刻就會回到vb 的下一行程式,無法做到等待該Process結束時,才執行下一行指令,或是說,無法得知該Process是否已結束,甚者,該Process執行到一半,又該如何中止其執行等等,這些都不是Shell指令所能控制的,是以我們需使API的幫助來完成。
第一個問題,如何等待shell所Create的process結束後才往後執行vb的程式。首先要知道的是,每個Process有唯一的一個ProcessID,這是OS給定的,用來差別每個 Process,這個Process ID(PID)主要可用來取得該Process相對應的一些資訊,然而要對該Process的控制,卻大多透過 Process Handle(hProcess)。
VB Shell指令的傳回值是PID,而非hProcess,是以我們需透過OpenProcess這個API來取得 hProcess而OpenProcess()的第一個叁數,指的是所取得的hProcess所具有的能力,像 PROCESS_QUERY_INFORMATION 便是讓GetExitCode()可取得hProcess所指的process之狀态,而PROCESS_TERMINATE,便是讓TerminateProcess(hProcess..)的指令能夠生效,也就是說,不同叁數設定,使hProcess所具有的權限、能力有所不同。
取得 hProcess後便可以使用WaitForSingleObject()來等待hProcess狀态的改變,也就是說,它會等待 hProcess所指的process執行完,這個指令才結束,它第二個叁數所指的是 WaitForSingleObject()所要等待的時間(in milliseconds ),如果超過所指的時間,就TimeOut而結束WaitForSingleObject()的等待。若要它無限的等下去,就設定為INFIN99vE。
pid = Shell("C:/tools/spe3/pe2.exe", vbNormalFocus)
hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, 0, pid)
ExitEvent = WaitForSingleObject(hProcess, INFIN99vE)
Call CloseHandle(hProcess)
上例會無限等待shell指令create之process結束後,才再做後面的vb指令。有時覺得那會等太久,是以有第二個解決方式:
等process結束時再通知vb 就好,即:設定一個公用變數(isDone),當它變成True時代表Shell所Create的Process已結束。
當Process還在執行時,GetExitCodeProcess會傳&H103給其第二個叁數,直到結束時才傳另外的數值,如果程式正常結束,那Exitcode = 0,否則就得看它如何結束了。
或許有人在其他地方看到 loop的地方是Loop while Exitcode <> 0,那有一點危險,如果以這程子來看,您不是用F4來離開pe2而是用右上方 X 的結束dos window那麽,會因為ExitCode的值永遠不會是0,而進入無窮的回圈。
Dim pid As Long
pid = Shell("C:/tools/spe3/pe2.exe", vbNormalFocus)
hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, 0, pid)
isDone = False
Do
Call GetExitCodeProcess(hProcess, ExitCode)
Debug.Print ExitCode
DoEvents
Loop While ExitCode = STILL_ALIVE
Call CloseHandle(hProcess)
isDone = True
另外,如果您的shell所Create的程式,有視窗且為立刻Focus者,可另外用以下的方式:
Dim pid As Long
Dim hwnd5 As Long
pid = Shell("c:/tools/spe3/pe2.exe", vbNormalFocus)
hwnd5 = GetForegroundWindow()
isDone = False
Do While IsWindow(hwnd5)
DoEvents
Loop
isDone = True
而如何強迫shell所Create的process結束呢,那便是
Dim aa As Long
If hProcess <> 0 Then
aa = TerminateProcess(hProcess, 3838)
End If
hProcess便是先前的例子中所取得的那個Process Handle, 3838所指的是傳給GetExitCodeProcess()中的第二叁數,這是我們任意給的,但最好不要是0,因為0一般是代表正常結束,當然這樣設也不會有錯。當然不可設&H103,以這個例子來看,如果程式正處於以下的LOOP
Do
Call GetExitCodeProcess(hProcess, ExitCode)
Debug.Print ExitCode
DoEvents
Loop While ExitCode = STILL_ALIVE
Debug.print ExitCode
而執行了 TerminateProcess(hProcess, 3838)那會看到ExitCode = 3838。
然而,這個方式在win95沒問題,在NT中,可能您要在OpenProcess()的第一個叁數要更改成 PROCESS_QUERY_INFORMATION Or PROCESS_TERMINATE 這樣才能Work。不過良心的建議,非到最後關頭,不要使用TerminateProcess(),因不正常的結束,往往許多程式結束前所要做的事都沒有做,可能造成Resource的浪費,甚者,下次再執行某些程式時會有問題,例如:本人常使用MS-dos Shell Link 的方式執行一程式,透過Com port與大電腦的聯結,如果Ms-dos Shell Link 不正常結束,下次再想Link時,會發現too Many Opens,這便是一例。
另外,有人使用Shell來執行.bat檔,即:
pid = Shell("c:/aa.bat", vbNormalFocus)
可是卻遇上aa.bat結束了,但ms-dos的Window卻仍活着,那可以用以下的方式來做
pid = Shell("c:/command.com /c c:/aa.bat", vbNormalFocus)
那是執行Command.com,而Command.com指定執行c:/aa.bat 而且結束時自動Close,所有程式如下:
Private Declare Function OpenProcess Lib "kernel32" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Private Declare Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function GetExitCodeProcess Lib "kernel32" (ByVal hProcess As Long, lpExitCode As Long) As Long
Private Declare Function TerminateProcess Lib "kernel32" (ByVal hProcess As Long, ByVal uExitCode As Long) As Long
Private Declare Function GetForegroundWindow Lib "user32" () As Long
Private Declare Function IsWindow Lib "user32" (ByVal hwnd As Long) As Long
Const PROCESS_QUERY_INFORMATION = &H400
Const STILL_ALIVE = &H103
Const INFIN99vE = &HFFFF
Private ExitCode As Long
Private hProcess As Long
Private isDone As Long
Private Sub Command1_Click()
Dim pid As Long
pid = Shell("C:/tools/spe/pe2.exe", vbNormalFocus)
hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, 0, pid)
isDone = False
Do
Call GetExitCodeProcess(hProcess, ExitCode)
Debug.Print ExitCode
DoEvents()
Loop While ExitCode = STILL_ALIVE
Call CloseHandle(hProcess)
isDone = True
End Sub
Private Sub Command2_Click()
Dim pid As Long
Dim ExitEvent As Long
pid = Shell("C:/tools/spe3/pe2.exe", vbNormalFocus)
hProcess = OpenProcess(PROCESS_QUERY_INFORMATION, 0, pid)
ExitEvent = WaitForSingleObject(hProcess, INFIN99vE)
Call CloseHandle(hProcess)
End Sub
Private Sub Command3_Click()
Dim aa As Long
If hProcess <> 0 Then
aa = TerminateProcess(hProcess, 3838)
End If
End Sub
Private Sub Command4_Click()
Dim pid As Long
Dim hwnd5 As Long
pid = Shell("c:/tools/spe3/pe2.exe", vbNormalFocus)
hwnd5 = GetForegroundWindow()
isDone = False
Do While IsWindow(hwnd5)
DoEvents()
Loop
isDone = True
End Sub
Private Sub Command5_Click()
Dim pid As Long
'pid = Shell("c:/windows/command/xcopy c:/aa.bat a:", vbHide)
pid = Shell("c:/command.com /c c:/aa.bat", vbNormalFocus)
End Sub
===================================================================================
===================================================================================
在使用shell後,如何等待此程式完成後,程式才繼續執行.我們使用 shell 調用一個外部程式的時候,通常 vb(a) 會在調用之後繼續下面的語句,而不管此 shell 程式執行完成沒有.有時我們需要在此 shell 執行完成之後才繼續,又當如何呢?請看源程:
Public Declare Function OpenProcess Lib "kernel32" Alias "OpenProcess" (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, ByVal dwProcessId As Long) As Long
Public Declare Function WaitForSingleObject Lib "kernel32" Alias "WaitForSingleObject" (ByVal hHandle As Long, ByVal dwMilliseconds As Long) As Long
Public Declare Function CloseHandle Lib "kernel32" Alias "CloseHandle" (ByVal hObject As Long) As Long
Dim lngPId As Long
Dim lngPHandle As Long
lngPId = Shell("Notepad", vbNormalFocus)
lngPHandle = OpenProcess(SYNCHRONIZE, 0, lngpId)
If lngPHandle <> 0 Then
Call WaitForSingleObject(lngPHandle, INFINITE) ' 無限等待, 直到程式結束
Call CloseHandle(lngPHandle)
End If
需要注意的是,在 shell 程式未完成前,你的程式不能做任何事,請小心為之。
=============================================================================
=============================================================================
Private Declare Function WaitForSingleObject Lib "kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function ShellExecuteEx Lib "shell32.dll" Alias "ShellExecuteExA" (lpInfo As Any) As Long
Private Type SHELLEXECUTEINFO
cbSize As Long
fMask As Long
hwnd As Long
lpVerb As String
lpFile As String
lpParameters As String
lpDirectory As String
nShow As Long
hInstApp As Long
'Optional members
lpIDList As Long
lpClass As String
hkeyClass As Long
dwHotKey As Long
hIcon_OR_Monitor As Long
hProcess As Long
End Type
Private Sub Form_Load()
Dim si As SHELLEXECUTEINFO
si.cbSize = Len(si)
si.lpVerb = "open"
si.lpFile = "notepad.exe"
si.lpParameters = ""
si.lpDirectory = ""
si.nShow = 5 'SW_SHOW
si.fMask = &H40 'SEE_MASK_NOCLOSEPROCESS
ShellExecuteEx si
If si.hProcess <> 0 Then
WaitForSingleObject(si.hProcess, &HFFFFFFFF) ' 無限等待, 直到程式結束
CloseHandle si.hProcess
MsgBox "程式運作完畢!"
End If
End Sub
============================================
=============================================
shell指令一觀:
shell "cmd /c dir",1'/c表示執行完即關閉視窗
shell "cmd /k dir",1'/k表示執行完停留
shell "cmd /c dir && pause",1'多條語句可用&&連接配接
關于cmd的具體用法可以在指令提示符下敲入cmd/?看看太多了,隻列舉一些典型的:
CMD [/A | /U] [/Q] [/D] [/E:ON | /E:OFF] [/F:ON | /F:OFF] [/V:ON | /V:OFF] [[/S] [/C | /K] string]
/C 執行字元串指定的指令然後終斷
/K 執行字元串指定的指令但保留
/S 在 /C 或 /K 後修改字元串處理(見下)
/Q 關閉回應
/D 從系統資料庫中停用執行 AutoRun 指令(見下)
/A 使向内部管道或檔案指令的輸出成為 ANSI
/U 使向内部管道或檔案指令的輸出成為 Unicode
/T:fg 設定前景/背景顔色(詳細資訊,請見 COLOR /?)
/E:ON 啟用指令擴充(見下)
/E:OFF 停用指令擴充(見下)
/F:ON 啟用檔案和目錄名稱完成字元 (見下)
/F:OFF 停用檔案和目錄名稱完成字元(見下)
/V:ON 将 ! 作為定界符啟動延緩環境變量擴充。
如: /V:ON 會允許 !var! 在執行時允許 !var! 擴充變量 var。var 文法在輸入時擴充變量,這與在一個 FOR 循環内不同。
/V:OFF 停用延緩的環境擴充。