XMLHTTP onTimeOut 时如何使用 VBA 回调函数？
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How to VBA callback function when XMLHTTP onTimeOut?
提问by Davuz
I'm trying get xml data from webserver to excel, then I wrote a sendRequestfunction to call in excel
我正在尝试从网络服务器获取 xml 数据到 excel，然后我编写了一个sendRequest函数来调用 excel
=sendRequest("http://abb.com/index.php?id=111")
=sendRequest("http://abb.com/index.php?id=111")
When web-server having trouble, cannot connect or cannot find, excel is not responding, it was horrible! To avoid it, i think we should set timeOut. These are my function:
当网络服务器出现问题、无法连接或找不到时，excel 没有响应，太可怕了！为了避免它，我认为我们应该设置超时。这些是我的功能：
Function sendRequest(Url)
'Call service
Set XMLHTTP = CreateObject("Msxml2.ServerXMLHTTP.6.0")
'Timeout values are in milli-seconds
lResolve = 10 * 1000
lConnect = 10 * 1000
lSend = 10 * 1000
lReceive = 15 * 1000 'waiting time to receive data from server
XMLHTTP.setTimeOuts lResolve, lConnect, lSend, lReceive
XMLHTTP.OnTimeOut = OnTimeOutMessage 'callback function
XMLHTTP.Open "GET", Url, False
On Error Resume Next
XMLHTTP.Send
On Error GoTo 0
sendRequest = (XMLHTTP.responseText)
End Function
Private Function OnTimeOutMessage()
'Application.Caller.Value = "Server error: request time-out"
MsgBox ("Server error: request time-out")
End Function
Normally, when XMLHTTP's timeout occurs, event OnTimeOutMessagewill be executed (reference #1, #2). But as in my test, OnTimeOutMessageis executed right at the beginning of sendRequest()
通常，当XMLHTTP的超时发生时，事件OnTimeOutMessage将被执行（参考#1, #2）。但是在我的测试中，OnTimeOutMessage在开始时执行sendRequest()
How to use callback function when Msxml2.ServerXMLHTTP.6.0request is time-out?
Msxml2.ServerXMLHTTP.6.0请求超时时如何使用回调函数？
Thank for your help!
感谢您的帮助！
采纳答案by Alex K.
The line;
线；
XMLHTTP.OnTimeOut = OnTimeOutMessage
XMLHTTP.OnTimeOut = OnTimeOutMessage
Is not a method assignment; rather it immediately executes OnTimeOutMessage()(and assigns its useless return value to OnTimeOut).
不是方法赋值；而是立即执行OnTimeOutMessage()（并将其无用的返回值分配给OnTimeOut）。
The equivalent line in JavaScriptas per your example link correctly assigns a Functionobject to OnTimeOutfor subsequent invokation - this is not supported by VBA.
根据您的示例链接，JavaScript 中的等效行正确Function地OnTimeOut为后续调用分配了一个对象- VBA 不支持这一点。
Instead, you could trap the timeout error raised after .sendor use early binding, WithEvents, & inline event handlers.
相反，您可以捕获在.send或使用早期绑定、WithEvents、 和内联事件处理程序之后引发的超时错误。
回答by osknows
Tim is correct in that if you have timeouts then each request will 'hang' Excel/VBA until the timeout duration has elapsed before continuing. Using async will allow you multiple requests without a long request delaying either a response or further requests.
蒂姆是正确的，因为如果您有超时，那么每个请求都会“挂起”Excel/VBA，直到超时持续时间过去，然后才能继续。使用 async 将允许您进行多个请求，而不会延迟响应或进一步请求的长请求。
The status property represents the HTTP status code returned by a request. Just place the code below in your existing code for a slower synchronous check or move your response processing to an event handler for async.
status 属性表示请求返回的 HTTP 状态代码。只需将下面的代码放在您现有的代码中以进行较慢的同步检查或将您的响应处理移动到异步事件处理程序。
XMLHTTP.Send
If XMLHTTP.Status = "200" Then
'200 OK
htmlString = XMLHTTP.ResponseText
Elseif XMLHTTP.Status = "408" Then
'408 Request Timeout
Call OnTimeOutMessage
else
'All status return values
'Number Description
'100 Continue
'101 Switching protocols
'200 OK
'201 Created
'202 Accepted
'203 Non-Authoritative Information
'204 No Content
'205 Reset Content
'206 Partial Content
'300 Multiple Choices
'301 Moved Permanently
'302 Found
'303 See Other
'304 Not Modified
'305 Use Proxy
'307 Temporary Redirect
'400 Bad Request
'401 Unauthorized
'402 Payment Required
'403 Forbidden
'404 Not Found
'405 Method Not Allowed
'406 Not Acceptable
'407 Proxy Authentication Required
'408 Request Timeout
'409 Conflict
'410 Gone
'411 Length Required
'412 Precondition Failed
'413 Request Entity Too Large
'414 Request-URI Too Long
'415 Unsupported Media Type
'416 Requested Range Not Suitable
'417 Expectation Failed
'500 Internal Server Error
'501 Not Implemented
'502 Bad Gateway
'503 Service Unavailable
'504 Gateway Timeout
'505 HTTP Version Not Supported
End If
