在做跨域接口调用的时候，写了个handler，在本地部署好了之后测试是可以用的，但是供外部链接调用的时候返回了405 method not allowed，解决办法如下：
<system.webServer> <httpProtocol> <customHeaders> <add name="Access-Control-Allow-Origin" value="*" /> <add name="Access-Control-Allow-Headers" value="X-Requested-With,Content-Type" /> <add name="Access-Control-Allow-Methods" value="GET, POST, PUT, DELETE, OPTIONS" /> </customHeaders> </httpProtocol> <handlers> <remove name="WebDAV" /> <remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" /> <remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" /> <remove name="ExtensionlessUrlHandler-Integrated-4.0" /> <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" /> <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" /> <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" /> <add name="handler" path="handler.ashx" verb="*" type="WebApp.handler"/> <remove name="OPTIONSVerbHandler" /> </handlers> <modules runAllManagedModulesForAllRequests="true"> <remove name="WebDAVModule" /> </modules> </system.webServer>
注意：
上述配置中，青色部分是结决跨域问题，红色部分是解决405错误的,
尤其要注意加粗部分，添加对应的handler文件，后面的type是"命名空间.类名"，如
namespace WebApp
{
/// <summary>
/// handler 的摘要说明
/// </summary>
public class handler : IHttpHandler
{
...
}