使用Excelmacrosauthentication文件下载

我有需要从互联网上下载大量的文件，所以我写了一个Excel的macros，通过引用网站。但现在我想下载一些文件从网站，这是密码保护以及如何改变我的代码，使它检查身份validation，并提出一个提示input用户名和密码，如果需要的话？ 在此先感谢这里是我的vba代码Sub DownloadFiles（）

'Declaring the necessary variables. Dim sh As Worksheet Dim DownloadFolder As String Dim LastRow As Long Dim SpecialChar() As String Dim SpecialCharFound As Double Dim FilePath As String Dim i As Long Dim j As Integer Dim Result As Long Dim CountErrors As Long Dim Username As String Dim Password As String Dim TextFile As Integer Dim CFilePath As String Dim Credentials As Variant 'Disable screen flickering. Application.ScreenUpdating = False 'Set the worksheet object to the desired sheet. Set sh = Sheets("Main") 'An array with special characters that cannot be used for naming a file. SpecialChar() = Split("\ / : * ? " & Chr$(34) & " < > |", " ") 'Find the last row. With sh .Activate LastRow = .Cells(.Rows.Count, "C").End(xlUp).Row End With 'Check if the download folder exists. DownloadFolder = sh.Range("B4") On Error Resume Next If Dir(DownloadFolder, vbDirectory) = vbNullString Then MsgBox "The folder's path is incorrect!", vbCritical, "Folder's Path Error" sh.Range("B4").Select Exit Sub End If On Error GoTo 0 'Check if there is at least one URL. If LastRow < 8 Then MsgBox "You did't enter a single URL!", vbCritical, "No URL Error" sh.Range("C8").Select Exit Sub End If 'Clear the results column. sh.Range("E8:E" & LastRow).ClearContents 'Add the backslash if doesn't exist. If Right(DownloadFolder, 1) <> "\" Then DownloadFolder = DownloadFolder & "\" End If 'Counting the number of files that will not be downloaded. CountErrors = 0 'Save the internet files at the specified folder of your hard disk. On Error Resume Next For i = 8 To LastRow 'Use the given file name. If Not sh.Cells(i, 4) = vbNullString Then 'Get the given file name. FilePath = sh.Cells(i, 4) 'Check if the file path contains a special/illegal character. For j = LBound(SpecialChar) To UBound(SpecialChar) SpecialCharFound = InStr(1, FilePath, SpecialChar(j), vbTextCompare) 'If an illegal character is found substitute it with a "-" character. If SpecialCharFound > 0 Then FilePath = WorksheetFunction.Substitute(FilePath, SpecialChar(j), "-") End If Next j 'Create the final file path. FilePath = DownloadFolder & FilePath 'Check if the file path exceeds the maximum allowable characters. If Len(FilePath) > 255 Then sh.Cells(i, 5) = "ERROR" CountErrors = CountErrors + 1 End If Else 'Empty file name. sh.Cells(i, 5) = "ERROR" CountErrors = CountErrors + 1 End If 'If the file path is valid, save the file into the selected folder. If UCase(sh.Cells(i, 5)) <> "ERROR" Then 'Try to download and save the file. Result = URLDownloadToFile(0, sh.Cells(i, 3), FilePath, 0, 0) 'Check if the file downloaded successfully and exists. If Result = 0 And Not Dir(FilePath, vbDirectory) = vbNullString Then 'Success! sh.Cells(i, 5) = "OK" Else 'Error! sh.Cells(i, 5) = "ERROR" CountErrors = CountErrors + 1 End If End If Next i On Error GoTo 0 'Enable the screen. Application.ScreenUpdating = True 'Inform the user that macro finished successfully or with errors. If CountErrors = 0 Then 'Success! If LastRow - 7 = 1 Then MsgBox "The file was successfully downloaded!", vbInformation, "Done" Else MsgBox LastRow - 7 & " files were successfully downloaded!", vbInformation, "Done" End If Else 'Error! If CountErrors = 1 Then MsgBox "There was an error with one of the files!", vbCritical, "Error" Else MsgBox "There was an error with " & CountErrors & " files!", vbCritical, "Error" End If End If 

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