如何在C#中使用VIES SOAP服务检查EU VAT

Question

我有一个ASP.NET网站,需要检查用户提供的增值税.所述VIES服务可用于该暴露一个SOAP API.

我需要一个关于如何使用此服务验证增值税的简单示例.在PHP中,它是以下4行:https://stackoverflow.com/a/14340495.对于C#,我发现2010年的一些文章不起作用,或者是几十行甚至几百行的"包装","辅助服务"等.

我不需要任何这些,有人可以提供类似PHP的四线程,可以在C#中检查增值税吗？谢谢.

Answer 1

这是一个自给自足的（没有 WCF，没有 WSDL，...）实用程序类，它将检查增值税号并获取有关公司的信息（名称和地址）。如果增值税号无效或发生任何错误，它将返回 null。

// sample calling code
Console.WriteLine(EuropeanVatInformation.Get("FR89831948815"));

...

public class EuropeanVatInformation
{
    private EuropeanVatInformation() { }

    public string CountryCode { get; private set; }
    public string VatNumber { get; private set; }
    public string Address { get; private set; }
    public string Name { get; private set; }
    public override string ToString() => CountryCode + " " + VatNumber + ": " + Name + ", " + Address.Replace("\n", ", ");

    public static EuropeanVatInformation Get(string countryCodeAndVatNumber)
    {
        if (countryCodeAndVatNumber == null)
            throw new ArgumentNullException(nameof(countryCodeAndVatNumber));

        if (countryCodeAndVatNumber.Length < 3)
            return null;

        return Get(countryCodeAndVatNumber.Substring(0, 2), countryCodeAndVatNumber.Substring(2));
    }

    public static EuropeanVatInformation Get(string countryCode, string vatNumber)
    {
        if (countryCode == null)
            throw new ArgumentNullException(nameof(countryCode));

        if (vatNumber == null)
            throw new ArgumentNullException(nameof(vatNumber));

        countryCode = countryCode.Trim();
        vatNumber = vatNumber.Trim().Replace(" ", string.Empty);

        const string url = "http://ec.europa.eu/taxation_customs/vies/services/checkVatService";
        const string xml = @"<s:Envelope xmlns:s='http://schemas.xmlsoap.org/soap/envelope/'><s:Body><checkVat xmlns='urn:ec.europa.eu:taxud:vies:services:checkVat:types'><countryCode>{0}</countryCode><vatNumber>{1}</vatNumber></checkVat></s:Body></s:Envelope>";

        try
        {
            using (var client = new WebClient())
            {
                var doc = new XmlDocument();
                doc.LoadXml(client.UploadString(url, string.Format(xml, countryCode, vatNumber)));
                var response = doc.SelectSingleNode("//*[local-name()='checkVatResponse']") as XmlElement;
                if (response == null || response["valid"]?.InnerText != "true")
                    return null;

                var info = new EuropeanVatInformation();
                info.CountryCode = response["countryCode"].InnerText;
                info.VatNumber = response["vatNumber"].InnerText;
                info.Name = response["name"]?.InnerText;
                info.Address = response["address"]?.InnerText;
                return info;
            }
        }
        catch
        {
            return null;
        }
    }
}

Answer 2

我发现的最简单的方法就是发送XML并在返回时对其进行解析：

var wc = new WebClient();
var request = @"<soapenv:Envelope xmlns:soapenv=""http://schemas.xmlsoap.org/soap/envelope/"" xmlns:urn=""urn:ec.europa.eu:taxud:vies:services:checkVat:types"">
    <soapenv:Header/>
    <soapenv:Body>
      <urn:checkVat>
         <urn:countryCode>COUNTRY</urn:countryCode>
         <urn:vatNumber>VATNUMBER</urn:vatNumber>
      </urn:checkVat>
    </soapenv:Body>
    </soapenv:Envelope>";

request = request.Replace("COUNTRY", countryCode);
request = request.Replace("VATNUMBER", theRest);

String response;
try
{
    response = wc.UploadString("http://ec.europa.eu/taxation_customs/vies/services/checkVatService", request);
}
catch
{
    // service throws WebException e.g. when non-EU VAT is supplied
}

var isValid = response.Contains("<valid>true</valid>");

Answer 3

在.NET平台上,通常使用Web服务以便生成代理类.这通常可以使用Visual Studio"添加Web引用"来完成,您只需填写WSDL的路径即可.另一种方法是使用wsdl.exe或svcutil.exe生成源类.

然后只需消耗这个类,验证增值税就变成了一个单行:

DateTime date = new checkVatPortTypeClient().checkVat(ref countryCode, ref vatNumber, out isValid, out name, out address);

生成代理提供强类型API以使用整个服务,我们不需要手动创建soap信封和解析输出文本.它比您的解决方案更容易,更安全,更通用.

Answer 4

更新：我已将其发布为 NuGet 库。

https://github.com/TriggerMe/CSharpVatChecker

var vatQuery = new VATQuery();
var vatResult = await vatQuery.CheckVATNumberAsync("IE", "3041081MH"); // The Squarespace VAT Number

Console.WriteLine(vatResult.Valid); // Is the VAT Number valid?
Console.WriteLine(vatResult.Name);  // Name of the organisation