急！！VB使用xmlhttp 分块下载大文件
我用vb 下载文件 文件小没有问题，文件大就会死掉 ，根据一般下载软件的分块下载，边下载边写文件，怎么下载完成的文件不能打开，下载后的文件比要下载的文件多几个字节，是怎么回事？？

xmlRequest.open "HEAD", strUrl, True      ' strUrl要下载的文件的地址
        xmlRequest.send Null
        '等待返回信息
        Do Until xmlRequest.readyState = 4
            DoEvents
        Loop
        strFileLen = xmlRequest.getResponseHeader("Content-Length") '获取下载的文件长度6186
        
        Num = strFileLen \ 4096
        If Dir(UpdataPath & NewFile) <> "" Then
            Kill UpdataPath & NewFile
        End If
        If Dir(UpdataPath, vbDirectory) = "" Then
            MkDir UpdataPath
        End If
            
        FileNum = FreeFile
        Open UpdataPath & NewFile For Binary As #FileNum     '二进制打开文件
            For i = 0 To Num
                xmlRequest.open "GET", strUrl, True
                'xmlRequest.setRequestHeader "Type", "application/octet-stream"
                If i = Num Then
                    xmlRequest.setRequestHeader "Range", "bytes=" & i * 4096 & "-"
                Else
                    xmlRequest.setRequestHeader "Range", "bytes=" & i * 4096 & "-" & (i + 1) * 4096 - 1
                End If
                xmlRequest.send Null
                '等待返回信息
                Do Until xmlRequest.readyState = 4
                    DoEvents
                Loop
                '判断是否还有下载
   '              NowFileLen = xmlRequest.getResponseHeader("Content-Length")
 '                ReDim FileBuff(CLng(NowFileLen) - 1)
 '                CopyMemory FileBuff(0), xmlRequest.responseBody(0), CLng(NowFileLen)
                
                Put #FileNum, , xmlRequest.responseBody
'                adoStream.Type = adTypeBinary
'                adoStream.open
'                adoStream.LoadFromFile UpdataPath & NewFile
'                adoStream.Position = i * 4096
'                adoStream.Write xmlRequest.responseStream
'                adoStream.SaveToFile UpdataPath & NewFile, adSaveCreateOverWrite
'                adoStream.Close
'
                
                
            Next i 
 

[解决办法]
忘了,是URL长度受限
[解决办法]
事件类（xmlEvent）代码：

Public xmlRequest As MSXML2.XMLHTTP
Public Event Complete()

Public Sub DownProc() '通过“工具”菜单下的“过程属性”菜单项弹出的过程属性对话框中“高级”按钮设置本过程为默认过程。
    If xmlRequest.readyState = 4 Then
        RaiseEvent Complete
    End If
End Sub

窗口代码：

Dim m_xmlRequest As New MSXML2.XMLHTTP
Dim WithEvents m_EventHandler As xmlEvent

Private Sub Command1_Click()
    '获得文件长度
    m_xmlRequest.open "HEAD", "HTTP://192.168.1.134/Vbe600chs1.rar", False
    m_xmlRequest.send
    Debug.Print "文件长度：", m_xmlRequest.getResponseHeader("Content-Length")

    '获得文件数据
    Set m_xmlRequest = New MSXML2.XMLHTTP
    Set m_EventHandler = New xmlEvent
    Set m_EventHandler.xmlRequest = m_xmlRequest
    m_xmlRequest.onreadystatechange = m_EventHandler
    m_xmlRequest.open "GET", "HTTP://192.168.1.134/Vbe600chs1.rar", True
    m_xmlRequest.send
End Sub

Private Sub m_EventHandler_Complete()
    '保存下载结果
    Open "c:\temp.rar" For Binary As #1
    Put #1, , m_xmlRequest.responseBody
    Close #1
    Debug.Print "下载文件长度：", UBound(m_xmlRequest.responseBody) + 1
End Sub

测试文件大小为220M，结果正确。