使用 .NET (dotnet) 通过 HTTPS 下载文件

我想使用 VB.NET（最好）或 C# 通过 HTTPS 下载文件。

我有以下代码可以通过纯 HTTP 下载文件：

Dim client As WebClient = New WebClient()
Dim wp As WebProxy = New WebProxy("[IP number of our proxy server]", [port number of our proxy server])
wp.Credentials = CredentialCache.DefaultCredentials
client.Proxy = wp
client.DownloadFile("http://sstatic.net/so/img/logo.png", "c:\logo.png")

这有效。

如何更改此代码以下载存储在 HTTPS 服务器上的文件？我猜这与添加凭据或其他东西有关。

您需要添加一个证书验证器：

// You need to call it only once in a static constructor or multiple times there is no problem
ServicePointManager.ServerCertificateValidationCallback = ValidateCertificate;

    private static bool ValidateCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
    {
        return true;
    }

In VB:

ServicePointManager.ServerCertificateValidationCallback = AddressOf ValidateCertificate
Dim client As WebClient = New WebClient()
'...
'Your code

  Private Shared Function ValidateCertificate(sender As Object, certificate As X509Certificate, chain As X509Chain, sslPolicyErrors As SslPolicyErrors) As Boolean
        return True
  End Function