VB下载网页文件或图片的几种简易方法

原贴链接:http://www.suntw.com/vb6/vb-xia-zhai-wang-ye-wen-jian-he-tu-pian.html

一、使用 API 函数 URLDownloadToFile，下载网页文件（也可以是图片等其他文件）到硬盘

Private Declare Function URLDownloadToFile Lib "urlmon" Alias "URLDownloadToFileA" (ByVal pCaller As Long, ByVal szURL As String, ByVal szFileName As String, ByVal dwReserved As Long, ByVal lpfnCB As Long) As Long

Dim nUrl As String, F As String, S As Long

nUrl = "http://www.baidu.com/img/baidu_logo.gif": F = App.Path & "\My-1.bmp" '下载百度图片

S = URLDownloadToFile(0, nUrl, F, 0, 0) '下载文件，0 表示成功

nUrl = "http://www.baidu.com": F = App.Path & "\Baidu.html" '下载百度首页的网页

S = URLDownloadToFile(0, nUrl, F, 0, 0) '下载文件，0 表示成功

二、使用 API 函数 OleLoadPicturePath，下载图片文件到变量，注意要勾选引用：OLE Automation

Private Declare Function OleLoadPicturePath Lib "oleaut32.dll" (ByVal szURLorPath As Long, ByVal punkCaller As Long, ByVal dwReserved As Long, ByVal clrReserved As OLE_COLOR, ByRef riid As TGUID, ByRef ppvRet As IPicture) As Long

Private Type TGUID

Data1 As Long: Data2 As Integer: Data3 As Integer: Data4(0 To 7) As Byte

End Type

Public Function LoadNetPicture(ByVal ImgSrc As String) As Picture

Dim riid As TGUID

riid.Data1 = &H7BF80980: riid.Data2 = &HBF32: riid.Data3 = &H101A

riid.Data4(0) = &H8B: riid.Data4(1) = &HBB: riid.Data4(2) = &H0

riid.Data4(3) = &HAA: riid.Data4(4) = &H0: riid.Data4(5) = &H30

riid.Data4(6) = &HC: riid.Data4(7) = &HAB

OleLoadPicturePath StrPtr(ImgSrc), 0&, 0&, 0&, riid, LoadNetPicture

End Function

'使用方法:

Dim ImgSrc As String, nPicture As Picture

ImgSrc = "http://www.baidu.com/img/baidu_logo.gif"

Set nPicture = LoadNetPicture(ImgSrc) '将图片下载到变量

SavePicture nPicture, App.Path & "\MyImg.bmp" '保存到硬盘

Picture1.Picture = nPicture

'如果要将图片装载到控件，可以直接这样：

Picture1.Picture = LoadNetPicture(ImgSrc)

三、使用 Microsoft.XMLHTTP 对象，下载网页文件（也可以是图片等其他文件）到硬盘

Private Sub DownNetFile(ByVal nUrl As String, ByVal nFile As String)

Dim XmlHttp, B() As Byte

Set XmlHttp = CreateObject("Microsoft.XMLHTTP")

XmlHttp.Open "GET", nUrl, False

XmlHttp.Send

If XmlHttp.ReadyState = 4 Then

B() = XmlHttp.ResponseBody

Open nFile For Binary As #1

Put #1, , B()

Close #1

End If

Set XmlHttp = Nothing

End Sub

'使用方法:

DownNetFile "http://www.baidu.com/img/baidu_logo.gif", App.Path & "\My-1.bmp" '下载百度图片

DownNetFile "http://www.baidu.com", App.Path & "\Baidu.html" '下载百度首页的网页

四、使用 WebBrowser 的 Document 对象，保存网页的所有图片

'先用 WebBrowser1 显示一个网页，如：WebBrowser1.Navigate "http://www.baidu.com"

'待网页加载完毕后，再执行以下语句：

Dim nPath As String, K As Long, E, nRange

nPath = App.Path & "\Tu\"

WebBrowser1.Silent = True '关闭交互 禁止脚本错误

For Each E In WebBrowser1.Document.All

If E.tagName = "IMG" Then

Set nRange = WebBrowser1.Document.body.createControlRange()

nRange.Add E

nRange.execCommand "Copy" '复制到剪贴板

K = K + 1

SavePicture Clipboard.GetData, nPath & K & ".bmp" '保存到硬盘

End If

Next

五、用API调用系统的另存为下载对话框

Private Declare Function DoFileDownload Lib "shdocvw.dll" (ByVal lpszFile As String) As Long

'使用方法：

Dim nUrl As String

nUrl = StrConv("http://www.baidu.com", vbUnicode)

Call DoFileDownload(nUrl)

六、用 WebBrowser1 的 ExecWB 方法调用网页另存为对话框：

WebBrowser1.ExecWB OLECMDID_SAVEAS, OLECMDEXECOPT_DODEFAULT

以上方法各有优缺点。

Microsoft.XMLHTTP 对于大文件有利，支持断点续传，但需调用 getResponseHeader 进行数据检查。

对于谷歌地图图片，图片链接形如 http://mt1.google.cn/vt/lyrs=s@63&gl=cn&x=51694&s=&y=26884&z=16&s=Galile，仅第四种方法有效。