vb中怎样判断已经存在的文件，当前是否已经打开

--//判断一个文件是否存在和是否打开

先引用：microsoft scripting runtime

如：贺巧D盘的上的aa.txt文件档腊

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Private Sub Command1_Click()

Dim hwndcalc As Integer

Dim fso As New FileSystemObject

If fso.FileExists("d:\aa.txt") = True Then

MsgBox "此文件存在！"

Else

MsgBox "此文件不存在！禅蠢键"

Exit Sub

End If

On Error GoTo err:

fso.CopyFile "d:\aa.txt", "e:\aa.txt", True

MsgBox "打开了！"

Exit Sub

err:

MsgBox "没打开!"

End Sub

用_access函数判断，再次打开时的情况要看你第一次的打开方式侍槐核了，如果上次用的是非独占打开，那没问题，如果是独占打开，会老掘打开失败

Example

/* ACCESS.C: This example uses _access to check the

* file named "ACCESS.C" to see if it exists and if

* writing is allowed.

*/

#include <io.h>

#include <stdio.h>

#include <明孙stdlib.h>

void main( void )

{

/* Check for existence */

if( (_access( "ACCESS.C", 0 )) != -1 )

{

printf( "File ACCESS.C exists\n" )

/* Check for write permission */

if( (_access( "ACCESS.C", 2 )) != -1 )

printf( "File ACCESS.C has write permission\n" )

}

}

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