方法一：webbrowser的outhtml法
利用webbrowser打開網頁，然後通過outhtml輸出源碼，再加以分析利用。
方法二：WebClient的Downloaddata法
利用webclient下載源碼，再加以分析利用。
方法三：XMLHTTP及流對象法
利用MSXML2.XMLHTTP與adodb.stream獲取源碼，再加以分析利用。
經過多次的測試，獲得源碼速度的排序是：
方法三 > 方法一 > 方法二
也就是說，用XMLHTTP的方法是獲得網頁源碼最快的方式。方法二所用時間是方法三的三倍，是方法一的二倍
下面我把幾個方法的主要過程（函數）列出來，大家可以參考指正
XMLHTTP及流對象法的基本函數
Function GetPage(ByVal url)
Dim Retrieval
Retrieval = CreateObject("MSXML2.XMLHTTP")
With Retrieval
.Open("Get", url, False) ', "", ""
.Send()
GetPage = BytesToBstr(.ResponseBody)
End With
Retrieval = Nothing
End Function
Function BytesToBstr(ByVal body)
Dim objstream
objstream = CreateObject("adodb.stream")
objstream.Type = 1
objstream.Mode = 3
objstream.Open()
objstream.Write(body)
objstream.Position = 0
objstream.Type = 2
objstream.Charset = "utf-8" '這裡是設定編碼的
BytesToBstr = objstream.ReadText
objstream.Close()
objstream = Nothing
End Function
WebClient的Downloaddata法的基本函數
Function gethtml(ByVal u As String, ByVal bm As String) As String
Dim Doc As New WebClient
Dim T As String = ""
Try
If bm = "utf-8" Then
T = System.Text.Encoding.UTF8.GetString(Doc.DownloadData(u))
ElseIf bm = "gb2312" Then
T = System.Text.Encoding.Default.GetString(Doc.DownloadData(u))
End If
Return T
Catch ex As Exception
Return ""
End Try
End Function
webbrowser的outhtml法的基本函數
利用WebBrowser的DocumentCompleted，獲取webBrowser1.Document.Body.OuterHtml
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VB.net保存遠程文件到本地並用進度條進行顯示的方法
首先在form裡添加一個ProgressBar，命名為prg1
然後指定要下載的文件路徑比如
dim remote as string ="http://www.abc.com/aa.exe" '遠程文件
dim local as string ="bb.exe" '本地文件
然後進行調用：
DownloadFile(remote, local,Me.prg1)
主函數：
Public Shared Sub DownloadFile(ByVal URL As String, ByVal Filename As String, ByVal Prog As ProgressBar)
Dim Myrq As HttpWebRequest = HttpWebRequest.Create(URL)
Dim myrp As HttpWebResponse = Myrq.GetResponse
Dim totalBytes As Long = myrp.ContentLength
Prog.Maximum = totalBytes
Dim st As Stream = myrp.GetResponseStream
Dim so As Stream = New FileStream(Filename, FileMode.Create)
Dim totalDownloadedByte As Long = 0
Dim by(1024) As Byte
Dim osize As Integer = st.Read(by, 0, by.Length)
While osize > 0
totalDownloadedByte = osize + totalDownloadedByte
System.Windows.Forms.Application.DoEvents()
so.Write(by, 0, osize)
Prog.Value = totalDownloadedByte
osize = st.Read(by, 0, by.LongLength)
End While
so.Close()
st.Close()
End Sub
VB 與 網路資源 (5)
