禁止程序多开

andymark

ACCESS本身也不允许程序打开多次,  但如果把程序复制到其他目录,  就可以程序多开了
有什么方法禁止上述的行为呢  ,  方法有好几种,  这里介绍CreateMutex 建立互斥体

模块代码

Private Declare Function CreateMutex Lib "kernel32" Alias "CreateMutexA" (ByVal lpMutexAttributes As Long, ByVal bInitialOwner As Long, ByVal lpName As String) As Long
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
  
'variable constant to match if the mutex exists
Private Const ERROR_ALREADY_EXISTS = 183&
  
'Application Variable Declarations
Public Const AppVer = "MyApp v1.1"
Public Function Test()

Dim Mutexvalue As Long
  
'*the following code would go in the starting function of your application
'either the main() or form_load() depending on how your application works
  
'Create an individual mutex value for the application
Mutexvalue = CreateMutex(ByVal 0&, 1, AppVer)
  Debug.Print Mutexvalue
'If an error occured creating the mutex, that means it
'must have already existed, therefore your application
'is already running
If (Err.LastDllError = ERROR_ALREADY_EXISTS) Then
  
'Inform the user of running the same app twice
MsgBox "The application is already running."
  
'Terminate the application via the reference to it, its hObject value
CloseHandle Mutexvalue
Application.Quit acQuitSaveNone
End If
End Function


测试例子

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huangqinyong

难得坐个沙发[:13]

changweiren

一定有用,谢谢楼主!

yori2007

[:50]

YCLOVE

一定有用

koutx

收藏备用

luhao

学习了

pcmanliu

下載來研究一下..

shiningdays

收藏了先！

W886655

总之，运算式在ACCESS中的应用是很广泛，包括：3 M% z6 u" n7 N0 _

* l4 k7 `" H! T5 |' W8 G% `0 @* VBA 模块控制流程与循环的条件判断
. O! \: M6 l; M  l
- p7 ^& L: [" i( b* e* SQL 指令的条件判断& t6 T  ~4 r% J$ B4 z* c2 m
7 q- K/ M. ^& ~7 v+ D
* 宏中的条件判断3 h* }+ X. E$ J' q( X) N
1 w0 d6 w# {. r
* 数据表字段中的默认值属性3 \& Q# U9 E( |! ]7 v9 `! j( [: O
$ P3 o& z1 \& X; O+ Y
* 数据表的验证规则属性
' e/ V5 i" z6 ?
# \+ l! j5 y0 k# o2 j4 U* 查询中建立的计算字段
- y) J  p6 h. Z, j* _) z# i8 b. w9 Q" k2 c( [/ G
* 输入字段中准则属性1 O4 x) e7 D- S8 [
' L$ p9 t1 M4 H" n
    运算式虽然很重要,但是它的结构很简单，依照运算符所需要的运算元数量来分共有两类：
" M4 Q0 y$ ]& Z  C3 h5 X( q
  H' |4 H# d2 k& Z( l* 单运算元：每个运算符只需要一个运算元。其格式：