FileLen()获取文件大小出现负数

dlxhj

FileLen()获取文件大小时，如果文件超过2G，会出现负数，怎么处理。

lsdongjh

filelen返回的是long型的字节数，而long最大值为2147483647，换算成G，约为2G,也就是说，一旦超过2G,出错了

dlxhj

lsdongjh 发表于 2021-9-23 10:17
filelen返回的是long型的字节数，而long最大值为2147483647，换算成G，约为2G,也就是说，一旦超过2G,出错了

有什么函数可以解决？

lsdongjh

打开文件, 用double类型 读取 LOF

dlxhj

lsdongjh 发表于 2021-9-23 10:32
打开文件, 用double类型 读取 LOF

open "c:\1.mpg" for input as #1
a= lof(1)
close #1

这样还是会出错，出现负数？

x-xx-xx

我刚刚也遇到了，改用fso了

小fisher

1. #If VBA7 Then
   
2. Private Declare PtrSafe Function GetFileSizeEx Lib "kernel32" (ByVal hFile As LongPtr, ByRef FileSize As LARGE_INTEGER) As Long
   
3. Private Declare PtrSafe Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, _
   
4.     lpSecurityAttributes As LongPtr, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As LongPtr) As LongPtr
   
5. Private Declare PtrSafe Function CloseHandle Lib "kernel32" (ByVal hObject As LongPtr) As Long
   
6. Dim lngHandle As LongPtr
   
7. #Else
   
8. Private Declare Function GetFileSizeEx Lib "kernel32" (ByVal hFile As Long, FileSize As LARGE_INTEGER ) As Long
   
9. Private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, _
   
10.     lpSecurityAttributes As Long, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long
    
11. Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
    
12. Dim lngHandle As Long
    
13. #End If
    
14. Private Const GENERIC_WRITE = &H40000000
    
15. Private Const OPEN_EXISTING = 3
    
16. Private Const FILE_SHARE_READ = &H1
    
17. Private Const FILE_SHARE_WRITE = &H2
    
18. Private Type LARGE_INTEGER
    
19.     LowPart As Long
    
20.     HighPart As Long
    
21. End Type
    
22. Function GetFileSize(sFilename As String) As Double
    
23.     Dim liFileSize As LARGE_INTEGER, lResult As Long
    
24.     lngHandle = CreateFile(sFilename, GENERIC_WRITE, FILE_SHARE_READ Or FILE_SHARE_WRITE, ByVal 0&, OPEN_EXISTING, 0, 0)
    
25.     lResult = GetFileSizeEx(lngHandle, liFileSize)
    
26.     CloseHandle lngHandle
    
27.     Dim a As Double
    
28.     a = 2 ^ 32
    
29.     If lResult <> 0 Then
    
30.         If liFileSize.LowPart >= 0 Then
    
31.             GetFileSize = liFileSize.HighPart * a + liFileSize.LowPart
    
32.         Else
    
33.             GetFileSize = (liFileSize.HighPart + 1) * a + liFileSize.LowPart
    
34.         End If
    
35.     End If
    
36. End Function
    
37. 
    
38. '用法演示
    
39. Sub test()
    
40.     MsgBox GetFileSize("E:\JZ_WIN10_X64_V2022.07.iso")
    
41. End Sub
    

复制代码

小fisher

lsdongjh 发表于 2021-9-23 10:32
打开文件, 用double类型 读取 LOF

LOF函数的定义是Function LOF(FileNumber As Integer) As Long，所以用double类型，也只是把返回的Long转为Double

perfect131

小fisher 发表于 2024-1-31 14:23

感谢分享
原来 FileLen的不足点 是没有 HighPart啊

perfect131

FileLen 只能计算 4G以下的 应该包含4G
2G~4G 是负值
负值 + 2^32(4gb)