Javascript to VB.Net [FEW LINES]

Javascript to VB.Net [FEW LINES]

本文关键字：FEW LINES Net to VB Javascript      更新时间：2023-09-26

我试图找出这个"POST"请求的作用，并将代码翻译成 vb.net，用于网络请求。将评论我已经知道的内容

var xmlhttp; //Defining the "xmlhttp" variable
    if (window.XMLHttpRequest) {
        xmlhttp = new XMLHttpRequest() 
    } else {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP")
    }
    xmlhttp.onreadystatechange = function() { //If the xmlhttp is created then do this:
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200) { //Don't know
            fired = true; //The function gathered the conditions to start
            var title = '<div id="message_box_title_unavailable">woops!</div>'; //Doesn't matter
            var result; //Variable "result"
            if (xmlhttp.responseText == 'available') { //If the xml file contains "available" on it then do this, else return an error...
                result = 'The name you selected <strong>' + user + 'is available!'
            } else {
                result = 'There was an error processing your request.  Please try again.'
            }
        }
    };
    xmlhttp.open("POST", "Checkusername.php", true); //Didn't I translate this correctly?
    xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded"); //What am I missing from this line in my vb code?
    xmlhttp.send("name=" + name + "&n=" + Math.random()) //The same...
}

好的 - 我的 Vb 翻译

Dim req As HttpWebRequest
Dim res As HttpWebResponse
Dim cookies As New CookieContainer()
req = WebRequest.Create("http://blablabla.net/Checkusername.php?name=" & name "&n=" R.Next(0, 20000))
req.Method = "POST"
req.ContentType = "application/xml"
req.Headers.Add("Content-type", "application/x-www-form-urlencoded")
req.CookieContainer = cookies
res = req.GetResponse
Dim webStream As Stream
webStream = res.GetResponseStream
Dim reader As New StreamReader(webStream)
checksource.text = reader.readtoend
这

总是向我返回一个"错误"而不是所需的结果，这在 HTML 中总是正确的

基本上，我无法翻译第 3/5 行和最后 3 行。

感谢您帮助大家！

当你做一个 GET 时，你在 url 中提供参数。当您执行 POST 时，您可以在请求中提供它们。此外，如果您不使用它，不确定为什么要创建 cookie 对象。

您不需要：

Dim res As HttpWebResponse
Dim cookies As New CookieContainer()

试试这个：

'Create the post string which contains the params
Dim postString As String = "name=" & name & "&n=" & R.Next(0, 20000)
'Create the request
req = WebRequest.Create("http://blablabla.net/Checkusername.php")
req.Method = "POST"
req.ContentLength = postString.Length
req.ContentType = "application/x-www-form-urlencoded"
'put the POST params in the request
Dim requestWriter As StreamWriter = New StreamWriter(req.GetRequestStream())
requestWriter.Write(postString)
requestWriter.Close()
'submit the request and read the response
Dim responseReader As StreamReader = New StreamReader(req.GetResponse().GetResponseStream())
Dim responseData As String = responseReader.ReadToEnd()
'close everything
responseReader.Close()
req.GetResponse().Close()
响应

数据将包含您的响应字符串

您还可以用 Try/Catch 包围它以检查是否有任何异常......互联网连接不良，网址错误，无响应等。 html 中的xmlhttp.readyState == 4 && xmlhttp.status == 200表示request finished和OK

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