我不知道您是否还在寻找实现此目的的方法。可以做到的。这是一个示例CORS处理程序
using System;using System.Collections.Generic;using System.Linq;using System.Net;using System.Net.Http;using System.Text;using System.Threading;using System.Threading.Tasks;namespace Api.Handlers{ /// <summary> /// /// </summary> public class CorsHandler : DelegatingHandler { const string Origin = "Origin"; const string AccessControlRequestMethod = "Access-Control-Request-Method"; const string AccessControlRequestHeaders = "Access-Control-Request-Headers"; const string AccessControlAllowOrigin = "Access-Control-Allow-Origin"; const string AccessControlAllowMethods = "Access-Control-Allow-Methods"; const string AccessControlAllowHeaders = "Access-Control-Allow-Headers"; /// <summary> /// /// </summary> /// <param name="request"></param> /// <param name="cancellationToken"></param> /// <returns></returns> protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken) { bool isCorsRequest = request.Headers.Contains(Origin); bool isPreflightRequest = request.Method == HttpMethod.Options; if (isCorsRequest) { if (isPreflightRequest) { HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK); response.Headers.Add(AccessControlAllowOrigin, request.Headers.GetValues(Origin).First()); string accessControlRequestMethod = request.Headers.GetValues(AccessControlRequestMethod).FirstOrDefault(); if (accessControlRequestMethod != null) { response.Headers.Add(AccessControlAllowMethods, accessControlRequestMethod); } string requestedHeaders = string.Join(", ", request.Headers.GetValues(AccessControlRequestHeaders)); if (!string.IsNullOrEmpty(requestedHeaders)) { response.Headers.Add(AccessControlAllowHeaders, requestedHeaders); } TaskCompletionSource<HttpResponseMessage> tcs = new TaskCompletionSource<HttpResponseMessage>(); tcs.SetResult(response); return tcs.Task; } return base.SendAsync(request, cancellationToken).ContinueWith<HttpResponseMessage>(t => { HttpResponseMessage resp = t.Result; resp.Headers.Add(AccessControlAllowOrigin, request.Headers.GetValues(Origin).First()); return resp; }); } return base.SendAsync(request, cancellationToken); } }}添加此代码后，然后在Application_Start方法内的Global.asax文件中注册处理程序。
GlobalConfiguration.Configuration.MessageHandlers.Add(new CorsHandler());
现在，您可以发送请求标头。希望有帮助。已通过Web API，MVC 4以及来自Google Chrome和Firefox的站点进行了测试。
