如何使用 HTTP 下載檔案
出自VFP Wiki
（修訂版本間差異）
在2005年11月11日 (五) 23:15所做的修訂版本
來源: http://support.microsoft.com/default.aspx?scid=kb;en-us;311306
此文章使用了兩個方法,一個是使用 urlmon.dll,另外一個則是使用 msinet active x.
using urlmon.dll
*-----------------------------------
* AUTHOR: Trevor Hancock (TREVORH@MICROSOFT.COM)
* CREATED: 10/24/01 03:07:28 PM for Microsoft Knowledge Base article Q311306
* ABSTRACT: Downloads a Web page and then parses the Web page to extract a stock quote.
*
* DETAILS: This code uses the function URLDownloadToFile(), located in
* Urlmon.dll. This function downloads a Web page from
* http://moneycentral.msn.com. Specifically, the function calls
* "http://moneycentral.msn.com/scripts/webquote.dll?iPage=lqd&Symbol=",
* passing to the Web page a stock symbol that the user types into THISFORM.txtSYMBOL.
* The Web site returns an entire page of information about the
* stock, which this code then parses to extract the current quote.
*-----------------------------------
PUBLIC ofrmURLMON
ofrmURLMON = NEWOBJECT("frmURLMON")
ofrmURLMON.SHOW
RETURN
**************************
DEFINE CLASS frmURLMON AS FORM
HEIGHT = 83
WIDTH = 317
AUTOCENTER = .T.
BORDERSTYLE = 2
CAPTION = "Stock Quote via URLMON.DLL"
MAXBUTTON = .F.
MINBUTTON = .F.
NAME = "frmURLMON"
ADD OBJECT txtsymbol AS TEXTBOX WITH ;
FONTNAME = "Verdana", ;
VALUE = "MSFT", ;
FORMAT = "!", ;
HEIGHT = 26, ;
LEFT = 94, ;
TABINDEX = 1, ;
TOP = 7, ;
WIDTH = 100, ;
NAME = "txtSymbol"
ADD OBJECT cmdGetQuote AS COMMANDBUTTON WITH ;
TOP = 7, ;
LEFT = 206, ;
HEIGHT = 27, ;
WIDTH = 94, ;
FONTNAME = "Verdana", ;
CAPTION = "Get Quote", ;
TABINDEX = 2, ;
NAME = "cmdGetQuote"
ADD OBJECT lblSymbol AS LABEL WITH ;
AUTOSIZE = .T., ;
FONTNAME = "Verdana", ;
CAPTION = "Stock Symbol:", ;
HEIGHT = 16, ;
LEFT = 3, ;
TOP = 12, ;
WIDTH = 90, ;
TABINDEX = 5, ;
NAME = "lblSymbol"
ADD OBJECT txtQuote AS TEXTBOX WITH ;
FONTNAME = "Verdana", ;
HEIGHT = 23, ;
LEFT = 94, ;
READONLY = .T., ;
TOP = 39, ;
WIDTH = 100, ;
NAME = "txtQuote"
ADD OBJECT lblQuote AS LABEL WITH ;
AUTOSIZE = .T., ;
FONTNAME = "Verdana", ;
CAPTION = "Quote:", ;
HEIGHT = 16, ;
LEFT = 47, ;
TOP = 42, ;
WIDTH = 46, ;
TABINDEX = 5, ;
NAME = "lbQuote"
PROCEDURE cmdGetQuote.CLICK
LOCAL lcQuote AS STRING, ;
lcTempTxtFile AS STRING, ;
lnGetResults AS INTEGER, ;
lcURL AS STRING
lcQuote = ""
*-- Set up a variable referring to a temp .TXT file.
*-- Uses the current VFP TEMP DIR [SYS(2023)]
*-- and a random file name [SYS(2015)]
lcTempTxtFile = FORCEEXT(ADDBS(SYS(2023)) + SYS(2015), "TXT")
lnGetResults = 0
lcGetURl = "http://moneycentral.msn.com/scripts/webquote.dll?iPage=qd&Symbol=" + ;
ALLT(THISFORM.txtsymbol.VALUE)
DECLARE LONG URLDownloadToFile IN URLMON.DLL ;
LONG, STRING, STRING, LONG, LONG
WITH THISFORM
*-- Get the quote using the Urlmon.dll and store it
*-- to a temp .TXT file.
*-- This function returns non-zero if it fails.
lnGetResults = URLDownloadToFile(0, lcGetURl, lcTempTxtFile, 0, 0)
IF lnGetResults # 0
MESSAGEBOX("Download Failed",0,"")
RETURN .F.
ENDIF
*-- Read the Web page into a variable, and then erase it.
lcQuote = FILETOSTR(lcTempTxtFile)
ERASE (lcTempTxtFile)
*-- Grab the quote from the Web page. If in VFP 7.0 or later, we use the new
*-- STREXTRACT() function to grab the data between two delimiters.
*-- In VFP 6.0, use SUBSTR() to get the data, and then trim off any
*-- trailing HTML with the TRANSFORM() AND VAL() functions.
IF VERSION(5) => 700
lcQuote = STREXTRACT(lcQuote, [Last ], [ ])
ELSE
*-- Extract the quote from the HTML
lcQuote = SUBSTR(lcQuote, ATC([Last ], lcQuote) + 16, 8)
*-- Trim off the trailing HTML. VAL() will only return the numbers,
*-- which we then change to a string with TRANSFORM()
lcQuote = TRANSFORM(VAL(lcQuote))
ENDIF
*-- Put the quote in the text box.
.txtQuote.VALUE = "$" + lcQuote
ENDWITH
ENDPROC
ENDDEFINE
****************
using msinet active x control
*-----------------------------------
* AUTHOR: Trevor Hancock (TREVORH@MICROSOFT.COM)
* CREATED: 10/24/01 03:07:28 PM for Microsoft Knowledge Base article Q311306
* ABSTRACT: Downloads a Web page and then parses it to extract a stock quote.
*
* DETAILS: This code uses the Msinet.ocx ActiveX control to
* download a Web page from http://moneycentral.msn.com. Specifically,
* the function calls "http://moneycentral.msn.com/scripts/webquote.dll?iPage=lqd&Symbol=",
* passing to the Web page a stock symbol that the user types into THISFORM.txtSYBMOL.
* The Web site returns an entire page of information about the
* stock, which this code then parses to extract the current quote.
*-----------------------------------
PUBLIC ofrmMSINET
ofrmMSINET = NEWOBJECT("frmMSINET")
ofrmMSINET.SHOW
RETURN
**************************
DEFINE CLASS ocxMSINET AS OLECONTROL
OLECLASS = "InetCtls.Inet.1"
ENDDEFINE
**************************
DEFINE CLASS frmMSINET AS FORM
HEIGHT = 70
WIDTH = 304
AUTOCENTER = .T.
BORDERSTYLE = 3
CAPTION = "Stock Quote via MSINET.OCX"
MAXBUTTON = .F.
MINBUTTON = .F.
NAME = "frmMSINET"
ADD OBJECT MSINET AS ocxMSINET WITH ;
TOP = 37, ;
LEFT = 234, ;
HEIGHT = 100, ;
WIDTH = 100, ;
NAME = "MSINET"
ADD OBJECT txtsymbol AS TEXTBOX WITH ;
FONTNAME = "Verdana", ;
VALUE = "MSFT", ;
FORMAT = "!", ;
HEIGHT = 26, ;
LEFT = 94, ;
TABINDEX = 1, ;
TOP = 7, ;
WIDTH = 100, ;
NAME = "txtSymbol"
ADD OBJECT cmdGetQuote AS COMMANDBUTTON WITH ;
TOP = 7, ;
LEFT = 206, ;
HEIGHT = 27, ;
WIDTH = 94, ;
FONTNAME = "Verdana", ;
CAPTION = "Get Quote", ;
TABINDEX = 2, ;
NAME = "cmdGetQuote"
ADD OBJECT lblSymbol AS LABEL WITH ;
AUTOSIZE = .T., ;
FONTNAME = "Verdana", ;
CAPTION = "Stock Symbol:", ;
HEIGHT = 16, ;
LEFT = 3, ;
TOP = 12, ;
WIDTH = 90, ;
TABINDEX = 5, ;
NAME = "lblSymbol"
ADD OBJECT txtQuote AS TEXTBOX WITH ;
FONTNAME = "Verdana", ;
HEIGHT = 23, ;
LEFT = 94, ;
READONLY = .T., ;
TOP = 39, ;
WIDTH = 100, ;
NAME = "txtQuote"
ADD OBJECT lblQuote AS LABEL WITH ;
AUTOSIZE = .T., ;
FONTNAME = "Verdana", ;
CAPTION = "Quote:", ;
HEIGHT = 16, ;
LEFT = 47, ;
TOP = 42, ;
WIDTH = 46, ;
TABINDEX = 5, ;
NAME = "lbQuote"
PROCEDURE cmdGetQuote.CLICK
LOCAL lcQuote AS STRING, ;
lcURL AS STRING
lcQuote = ""
lcGetURl = "http://moneycentral.msn.com/scripts/webquote.dll?iPage=qd&Symbol=" + ;
ALLT(THISFORM.txtsymbol.VALUE)
WITH THISFORM
*-- Get the quote using the Msinet.ocx ActiveX control.
*-- The control will load it directly into a variable.
lcQuote = .MSINET.OpenURL(lcGetURl)
IF EMPTY(lcQuote)
MESSAGEBOX("Download Failed.",0,"")
RETURN .F.
ENDIF
*-- Grab the quote from the Web page. If in VFP 7.0 or later, we use the new
*-- STREXTRACT() function to grab the data between two delimiters.
*-- In VFP 6.0, use SUBSTR() to get the data, and then trim off any
*-- trailing HTML with the TRANSFORM() AND VAL() functions.
IF VERSION(5) => 700
lcQuote = STREXTRACT(lcQuote, [Last ], [ ])
ELSE
*-- Extract the quote from the HTML
lcQuote = SUBSTR(lcQuote, ATC([Last ], lcQuote) + 16, 8)
*-- Trim off the trailing HTML. VAL() will only return the numbers,
*-- which we then change to a string with TRANSFORM()
lcQuote = TRANSFORM(VAL(lcQuote))
ENDIF
*-- Put the quote in the text box.
.txtQuote.VALUE = "$" + lcQuote
ENDWITH
ENDPROC
ENDDEFINE
**************************
