从 Silverlight 4 客户端访问 SOAP Web 服务

Question

我正在进行概念验证，从 Silverlight 4 客户端应用程序访问公共 Web 服务。当我尝试调用此示例公共 Web 服务时，出现以下错误：

An error occurred while trying to make a request to URI 'http://www.w3schools.com/webservices/tempconvert.asmx'. 
This could be due to attempting to access a service in a cross-domain way without a proper cross-domain policy in place, 
or a policy that is unsuitable for SOAP services. 
You may need to contact the owner of the service to publish a cross-domain policy file and to ensure it allows SOAP-related HTTP headers to be sent. 
This error may also be caused by using internal types in the web service proxy without using the InternalsVisibleToAttribute attribute. Please see the inner exception for more details.

我只能访问具有这些策略的 Web 服务吗？还是我根本没有在项目中正确配置 ASMX 服务？调用服务的代码如下：

   // Create
    var webServiceProxy = new TempConvert.TempConvertSoapClient();

    // Delegate
    webServiceProxy.FahrenheitToCelsiusCompleted += (s, args) =>
    {
        // Fail?
        if (args.Error != null)
        {
            // Message
            MessageBox.Show(string.Format("Something went wrong!\n\n{0}", args.Error.Message));
        }
        else
        {
            // Message
            MessageBox.Show(string.Format("50 f to c is {0}.", args.Result));
        }
    };

    // Call
    webServiceProxy.FahrenheitToCelsiusAsync("50");

Answer 1

如果您从计算机上运行此程序，则很可能会跨越域边界，并要求被调用站点制定从不同域进行调用的策略。

Microsoft 有大量相关信息，查找“silverlight跨域”以获取更多信息。

Answer 2

当服务器收到 url= /clientaccesspolicy.xml 的 GET 时
确保它的答案是：

<access-policy>
            <cross-domain-access>
                <policy>
                    <allow-from http-request-headers="*">
                        <domain uri="*"/>
                    </allow-from>
                    <grant-to>
                        <resource path="/" include-subpaths="true"/>
                    </grant-to>
                </policy>
            </cross-domain-access>