由于服务端SSL证书不可信，导致调用https的Web serivce 出现"基础连接已经断开"（
The underlying connection was closed）的错误，对于这个错误，可以使用代码忽略
.Net1.0的做法:
public class AcceptServerNameMismatch : ICertificatePolicy
{
// HACK: This is a workaround. The .NET Framwork should expose these, but they don't.
public enum CertificateProblem : long
{
CertEXPIRED = 2148204801,
CertVALIDITYPERIODNESTING = 2148204802,
CertROLE = 2148204803,
CertPATHLENCONST = 2148204804,
CertCRITICAL = 2148204805,
CertPURPOSE = 2148204806,
CertISSUERCHAINING = 2148204807,
CertMALFORMED = 2148204808,
CertUNTRUSTEDROOT = 2148204809,
CertCHAINING = 2148204810,
CertREVOKED = 2148204812,
CertUNTRUSTEDTESTROOT = 2148204813,
CertREVOCATION_FAILURE = 2148204814,
CertCN_NO_MATCH = 2148204815,
CertWRONG_USAGE = 2148204816,
CertUNTRUSTEDCA = 2148204818
}
/**//// <summary>
/// Implement CheckValidationResult to ignore problems that we are willing to accept.
/// </summary>
public bool CheckValidationResult(ServicePoint sp, X509Certificate cert,
WebRequest request, int problem)
{
/**//*
int CertificateNameDoesntMatch = unchecked( (int) CertificateProblem.CertCN_NO_MATCH);
if ( problem == CertificateNameDoesntMatch ) // only accept server name failed match
return true;
// The 1.1 framework calls this method with a problem of 0, even if nothing is wrong
return (problem == 0);
*/
return true;
}
}System.Net.ServicePointManager.CertificatePolicy = new AcceptServerNameMismatch(); .Net2.0+ 的做法，增加一个委托，在委托中判断并忽略
using System.Net.Security;
using System.Security.Cryptography.X509Certificates;
ServicePointManager.ServerCertificateValidationCallback +=
delegate(object sender, X509Certificate cert, X509Chain chain, SslPolicyErrors sslError)
{
bool validationResult = true;
return validationResult;
};