如何使用文件复制对话框？

Visual Basic 提供了过时的FileCopy语句.问题是使用该函数时并不显示文件复制对话框,也就是说,当拷贝一个大文件时,用户看不到Windows的标准
文件复制对话框,无法从进度条上判断当前复制的进度.那么,如何做到这一点呢?请看下面:

Public Type SHFILEOPSTRUCT
hWnd As Long
wFunc As Long
pFrom As String
pTo As String
fFlags As Integer
fAnyOperationsAborted As Boolean
hNameMappings As Long
lpszProgressTitle As String
End Type

Public Declare Function SHFileOperation Lib "shell32.dll" Alias
_
"SHFileOperationA" (lpFileOp As SHFILEOPSTRUCT) As Long
Public Const FO_COPY = &H2
Public Const FOF_ALLOWUNDO = &H40

Public Sub ShellCopyFile(Source As String, Dest As String)
Dim result As Long
Dim fileop As SHFILEOPSTRUCT
With fileop
.hwnd = 0
.wFunc = FO_COPY
'The files to copy separated by Nulls and terminated by 2 nulls
.pFrom = Source & vbNullChar & vbNullChar
'or to copy all files use this line
'.pFrom = "C:/*.*" & vbNullChar & vbNullChar
'The directory or filename(s) to copy into terminated in 2 nulls
.pTo = Dest & vbNullChar & vbNullChar
.fFlags = FOF_ALLOWUNDO
End With
result = SHFileOperation(fileop)
If result ＜＞ 0 Then 'Operation failed
'Msgbox the error that occurred in the API.
MsgBox Err.LastDllError, vbCritical Or vbOKOnly
Else
If fileop.fAnyOperationsAborted ＜＞ 0 Then
MsgBox "Operation Failed", vbCritical Or vbOKOnly
End If
End If
End Sub

只需调用ShellCopyFile FileA, FileACopy