如何从VB6使用Web服务？

VB6（Visual Basic 6）是一种面向对象的编程语言，自1991年首次发布以来，在各种应用程序中都得到了广泛的应用。然而，对于Web服务的操作，VB6在实现上并不太友好。尽管如此，如果您希望在VB6应用中实现某些Web服务，您可以尝试使用第三方库来实现它。例如，您可以使用SOAPlib库来轻松地与Web服务交互。

SOAPlib库是一个开源的、基于SOAP的Web服务客户端，专门用于VB6和.NET。它使用标准SOAP API来处理Web服务，无需编写过多的代码就能够实现多种服务的调用。

下面是一些步骤，您可以在VB6中使用SOAPlib库：

在您的VB6项目中引用SOAPlib库。您可以通过以下命令在您的VB6项目中导入它：' 引用SOAPlib库的文件位置 Private Declare Function soapinitialize Lib "soaplib.lib" () As Long Private Declare Sub soapfree Lib "soaplib.lib" (ByVal ptr As Long) Dim SOAPLIB_initialize, SOAPLIB_free As Long SOAPLIB_initialize = SoapInitialize ' 添加必要的引用 Private Type typSOAP xmlns As String xmlnsNamespace As String xmlnsLocalName As String xmlnsDelimiter() As String xmlnsNamespaceDelimiter() As String End Type Private Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" _ (ByVal pDest As Long, ByVal pSrc As Long, ByVal Length As Long) Private Type typSOAPHTTPBindings url As String username As String password As String End Type Private Declare Function wsainitialize Lib "Wsasprintf.DLL" (byval szNamespace As typSOAPHTTPBindings, byval szPrefix As String, byval _ szType As typSOAP, byval szName As String, byref szValue) As Long Private Const WsaSOAPVer1_0 = 43 Private Const WsaSOAPVer1_1 = 5 Private Const WsaSOAPVer1_2 = 6 Private Type typSOAPNSBinding NameSpace As String * 32 Prefix As typSOAP * 32 End Type ' 创建SOAPlib的HTTP绑定 Private Declare Function soapsoapbindingfunc\_CreateNS (ByRef soapNSBinding As typSOAPNSBinding, ByVal soapBindingType As typSOAP) As Long Private Declare Function soapsoapbindingfunc\_GetNS (ByRef nsbinding As typSOAPNSBinding, ByVal Prefix As typSOAP, byref \_ soapURL As String) As Long ' 创建SOAPlib的HTTP绑定并且注册一个命名空间 Private Declare Function soapsoapbindingfunc\_CreateNSEx (soap\_HttpBind \_ ByVal soapNSBinding As typSOAPNSBinding, \_ soap\_Verb As String, soap\_Method As String, ByVal soapTarget As String, byref \_ soapResponseText As String) As Long ' 调用HTTP请求并且解析响应 Private Declare Function soap\_http\_Call (soapUrl As String, \_ soapMethod As String, soapNsBinding As typSOAPNSBinding, \_ soapRequestData As String, byref soapResponseText As String) As Boolean ' 创建SOAPlib的HTTP调用 Private Declare Sub soap\_http\_CreateEx (ByRef soapRequestData As String, ByVal soapSOAPVer As Long, byref \_ soap\_HttpBind As typSOAPHTTPBindings, ByVal soapNsBinding As typSOAPNSBinding) As Boolean ' 初始化Soap消息头 Private Declare Function soap\_soapheaderfunc\_Create (soap\_Method As String) As Long ' 创建Soap消息头 Private Declare Function soap\_soapheaderfunc\_Get () As Long ' 插入Soap消息头 Private Declare Function soap\_soapheaderfunc\_Set (soap\_SoapData As String, soapType As typSOAP, \_ ByVal soapData As String) As Long Private Declare Function soap\_soapheaderfunc\_Get1 () As Long ' 从Soap消息中获取SoapHeader的值 Private Declare Function soap\_UncompressString (ByVal buf As String, ByVal Len As Long, byref \_ DecompressBuf As String) As Long Private Declare Function soapheaderfunc\_Get1Ex (soapHeader\_Info As typSOAP) As Long Private Declare Function soapheaderfunc\_Set1Ex (soapHeader\_Info As typSOAP, soap\_Method As String, \_ SoapData As String, ByVal soapType As typSOAP) As Long ' 创建一个新的变量，设置其类型为 SoapHeader Sub AssignNewHeader() Dim soapInfo As typSOAP soapInfo.NameSpace = "http://schemas.xmlsoap.org/soap/http" soapInfo.Prefix = "NS1" soapHeader\_Info.Name = "header1" soap\_soapheaderfunc\_Create soapInfo, "text/xml" End Sub ''' '调用HTTP请求并且解析响应 Sub HttpRequestExample() ' 声明 SOAPlib 中的 HTTP 绑定 soap\_http\_CreateEx soap\_HttpBind.url, WsaSOAPVer1_0, soap\_HttpBind.username, soap\_HttpBind.password ' 设置 HTTP 头信息中的 SOAP 版本为 1.0 soap\_http\_Set SoapHeader, soapHeader\_Info.Namespace, soapHeader\_Info.Prefix, WsaSOAPVer1_0 ' 获取 SOAPlib 当前所支持的 SOAP 版本，用于在调用相关方法之前设置相应的 HTTP 版本 If (soapHeader\_Info.Namespace = "http://schemas.xmlsoap.org/soap/soap/\") Then Dim xmlns\_ver As String xmlns\_ver = GetSoapHeaderVariable("soap-version") If (LenB(xmlns\_ver) >= 0) Then Select Case xmlns\_ver Case "1.0" soap\_http\_Call soap\_HttpBind.url, soapHeader\_Info.Name, soap\_soapheaderfunc\_Get(), soap\_SoapData, soap\_SoapResponseText Debug.Print soap\_SoapResponseText ' ... 在这里写调用响应程序的代码 ... ' 断开 HTTP 连接 soap\_http\_Destroy soap\_HttpBind Case Else MsgBox "当前 soap-version = " & xmlns\_ver & " 不支持。" End Select Unload Me Else MsgBox "当前 SOAPlib 库没有找到 soap-version 变量。" End If End Sub Private Sub GetSoapHeaderVariable(ByVal soap_header As String) soap\_UncompressString buf, LenB(buf), DecompressBuf Dim soap\_soapheader$ soap\_soapheader$ = Split(DecompressBuf, ";") soap\_soapheaderfunc\_Get1 soap\_soapheader$(0) End Sub Private Sub DebugCallResult(ByVal soap\_SoapResponseText As String) Debug.Print soap\_SoapResponseText End Sub
在程序中使用SOAPlib库，进行示例代码调用

AssignNewHeader

//创建一个变量，设置其类型为 SoapHeader

' 调用HTTP请求并且创建一个 Soap1.2 的消息头
SendMessage soap\_Method, soap\_HttpBind, vbNullString, "text/xml; charset=utf-8", vbNullString

使用SOAPlib库进行通信。需要注意的是，SOAPlib库使用的是HTTP协议，因此需要将程序的网络访问方式设置为"局域网"、"localhost"或计算机名而非"公共Internet"或IP地址，以保证安全性。同时，如果您访问的Web服务需要身份验证或权限时，您还需要为其配置相关访问权限，并在代码中使用合适的认证和授权模式。