C# 利用HttpRequestMessage设置cookie

var baseAddress = new Uri("http://example.com");
using (var handler = new HttpClientHandler { UseCookies = false //这里为false表示不采用HttpClient的默认Cookie,而是采用httpRequestmessage的Cookie})
using (var client = new HttpClient(handler) { BaseAddress = baseAddress })
{
    var message = new HttpRequestMessage(HttpMethod.Get, "/test");
    message.Headers.Add("Cookie", "cookie1=value1; cookie2=value2");
    var result = await client.SendAsync(message);
    result.EnsureSuccessStatusCode();
}

参考：http://stackoverflow.com/questions/12373738/how-do-i-set-a-cookie-on-httpclients-httprequestmessage