一、检查错误错误

将 httpwebresponse response = (httpwebresponse)request.getresponse();
改为 httpwebresponse response;
try
{
response = (httpwebresponse)request.getresponse();
}
catch (webexception ex)
{
response = (httpwebresponse)ex.response;
}

二、解决问题

如果抛出异常出现为:找到了与该请求匹配的多个操作

则修改webapi中的路由

config.routes.maphttproute(
name: “defaultapi”,
routetemplate: “api/{controller}/{id}”,
defaults: new { id = routeparameter.optional }
);
改为
config.routes.maphttproute(
name: “defaultapi”,
routetemplate: “api/{controller}/{action}/{id}”,
defaults: new { id = routeparameter.optional }
);