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程序问答发布时间：2022-06-01 发布网站：大佬教程 code.js-code.com

大佬教程收集整理的这篇文章主要介绍了当 url 正确时，VB.NET webrequest 返回 404，大佬教程大佬觉得挺不错的，现在分享给大家，也给大家做个参考。

如何解决当 url 正确时，VB.NET webrequest 返回 404？

开发过程中遇到当 url 正确时，VB.NET webrequest 返回 404的问题如何解决？下面主要结合日常开发的经验，给出你关于当 url 正确时，VB.NET webrequest 返回 404的解决方法建议，希望对你解决当 url 正确时，VB.NET webrequest 返回 404有所启发或帮助；

我已经在这尝试了几个小时。我正在将此代码从 Access 2010 项目移植到 vb.net 我不知道这里会出现什么问题。

Visual studio 2019，框架 4.7.2

    Dim data As Byte() = EnCoding.UTF8.GetBytes(strBody)
    url = "https://rest.avatax.com/API/v2/companIEs/" & OE2019HomeForm.strAvalaraCompany & "/certificates/"

    Dim uri As Uri = New Uri(url)

    Dim request As System.Net.Webrequest = System.Net.Webrequest.Create(uri)
    request.Method = "Post"
    request.headers.Add("40","Mozilla/5.0 (compatible; MSIE 10.0; windows NT 6.2; TrIDent/6.0)")
    request.headers.Add("Authorization","Basic " & OE2019HomeForm.strAuth)
    request.headers.Add("Cache-Control","no-cache")
    request.headers.Add("20","application/Json") 'this is the accept header
    request.headers.Add("12","text/plain") ' content type
    request.ContentLength = data.Length
    



    Dim stream As Stream = request.GetrequestStream()
    stream.Write(data,data.Length)
    stream.Close()

    Using response As WebResponse = request.GetResponse()
        Using responsestream As Stream = response.GetResponseStream()
            Using reader As StreamReader = New StreamReader(responsestream)
                Dim webresponse As String
                webresponse = reader.ReadToEnd()
                MsgBox(webresponsE)


            End Using
        End Using
    End Using

' 如果我在使请求变暗之前在下面添加一行，我会得到“'底层连接已关闭：接收时发生意外错误。'内部异常：Win32Exception：客户端和服务器无法通信，因为它们没有通用算法"

servicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3

任何帮助都会很棒。

解决方法

这对你有用吗？把它放在靠近顶部的地方。

    servicePointManager.SecurityProtocol = SecurityProtocolType.Tls Or SecurityProtocolType.Tls11 Or
        SecurityProtocolType.Tls12 Or SecurityProtocolType.Ssl3 Or SecurityProtocolType.Ssl3



    servicePointManager.ServerCertificateValidationCallBACk = Function(obj As [Object],certificate As X509Certificate,chain As X509Chain,errors As SslPolicyErrors) (true)