利用HttpWebRequest取得網頁資料的某部份

取得網頁資料的某部份

有時候我們想要取得某一個網頁的某一個部份的值
.NET裡面就有很好用的Class {System.Net} 裡的 HttpWebRequest

所以寫個簡單範例來看一下

Function GetPage(ByVal txtURL As String) As String

Dim strResponse As String
Dim strState As String
Dim strServer As String
Dim strTitle As String

Dim Result As String

Dim Request As HttpWebRequest
Dim Response As HttpWebResponse

Request = WebRequest.Create(txtURL)

Response = Request.GetResponse

Dim Answer As Stream
Dim SR As StreamReader

Answer = Response.GetResponseStream

SR = New StreamReader(Answer, Text.Encoding.UTF8)

strResponse = SR.ReadToEnd()

strState = Response.StatusCode.ToString

strServer = Response.Server

SR.Close()

If strState = "OK" Then
If strResponse.Length > 0 And strResponse.IndexOf("<title>") > 0 Then
strTitle = strResponse.Substring(strResponse.IndexOf("<title>") + 7, strResponse.IndexOf("</title>") - strResponse.IndexOf("<title>") - 7)
Result = strServer & "-" & strState & "-" & strTitle
Else
Result = strServer & "-" & strState & "-" & " XXXX "
End If
Else
Result = strServer & "-" & strState & "-" & " XXXX "
End If

Return Result

End Function

Protected Sub BTN_Search_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles BTN_Search.Click

LAB_Result.Text = GetPage(TB_URL.Text)

End Sub

結果顯示 -- WebServer名稱, 狀態, 網頁的Title