使用文件防止程序重复运行.frm

Windows API函数,希望大伙有用哦

VERSION 5.00
Begin VB.Form Form1 
   BackColor       =   &H80000018&
   Caption         =   "Form1"
   ClientHeight    =   1935
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   4680
   Icon            =   "使用文件防止程序重复运行.frx":0000
   LinkTopic       =   "Form1"
   ScaleHeight     =   1935
   ScaleWidth      =   4680
   StartUpPosition =   3  '窗口缺省
   Begin VB.CommandButton Command1 
      Caption         =   "退   出"
      Height          =   345
      Left            =   3060
      TabIndex        =   0
      Top             =   1350
      Width           =   1305
   End
   Begin VB.Label Label1 
      AutoSize        =   -1  'True
      BackStyle       =   0  'Transparent
      Caption         =   "欢迎使用本程序 ！"
      BeginProperty Font 
         Name            =   "华文行楷"
         Size            =   24
         Charset         =   134
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      ForeColor       =   &H00FF0000&
      Height          =   495
      Left            =   480
      TabIndex        =   1
      Top             =   510
      Width           =   3960
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Option Explicit
Private Sub Form_Load()
On Error GoTo A1
Dim FileName As String
' 从文件中读入程序运行信息
 Open App.Path + "\" + "AAA.txt" For Input As #1
 Input #1, FileName
 Close #1
' 如果有作为程序运行标志的数据则显示提示信息，单击确认按钮后停止本程序的运行
   If FileName = "X1" Then
    MsgBox "  本程序正在运行  ！ "
   End If
  Exit Sub
' 如果文件不存在则创建 AAA.txt 并将程序运行标志数写入文件
A1:
  FileName = "X1"
  Open App.Path + "\" + "AAA.txt" For Output As #1
  Write #1, FileName
  Close #1
End Sub
Private Sub Form_Unload(Cancel As Integer)
' 卸载窗体时从文件中删除数据
  Open App.Path + "\" + "AAA.txt" For Output As #1
    Write #1, ""
  Close #1
End Sub
Private Sub Command1_Click()
' 单击命令按钮，从文件中删除数据，停止程序运行
  Open App.Path + "\" + "AAA.txt" For Output As #1
    Write #1, ""
  Close #1
  Unload Me
  End
End Sub