调用 Webapi 跨域

先讲一下，web和client各自调用webapi的post和get实例

Get方式

[HttpGet]
        public dynamic Test(string a)
        {
            return a+"---";
        }

web调用

$.ajax({
                type: "Get",
                url: '../api/MyController/Test',
                dataType: "json",
data:"123",
                success: function (d) {
}
})

Client调用

static async void APIGet(string url)
        {
            //创建HttpClient（注意传入HttpClientHandler）
            var handler = new HttpClientHandler() { AutomaticDecompression = DecompressionMethods.GZip };

            using (var http = new HttpClient(handler))
            {
                //await异步等待回应
                var response = await http.GetAsync(url);
                //确保HTTP成功状态值
                response.EnsureSuccessStatusCode();

                //await异步读取最后的JSON（注意此时gzip已经被自动解压缩了，因为上面的AutomaticDecompression = DecompressionMethods.GZip）
                Console.WriteLine(await response.Content.ReadAsStringAsync());
            }
        }

Post方式

[HttpPost]
        public dynamic Test([FromBody]string data)
        {
            return data+"---";
        }

web调用

var data = { "": "123" };
$.ajax({
                    type: "Post",
                    url: "../api/MyController/Test",
                    dataType: "json",
                    data: data,
                    success: function (d) {

                    }
                });

client调用

public static async Task<string> APIPost(string url, string data)
        {
            string result = string.Empty;
            var handler = new HttpClientHandler() { AutomaticDecompression = DecompressionMethods.GZip };
            using (var http = new HttpClient(handler))
            {
                var content = new FormUrlEncodedContent(new Dictionary<string, string>()
                {
                  {"", data}//键名必须为空
                 });

                var response = await http.PostAsync(url, content);
                response.EnsureSuccessStatusCode();
                result = await response.Content.ReadAsStringAsync();
            }
            return result;
        }

方法1  配置web.config

对于跨域，比较简单的是配置web.config
<system.webServer> 节点下配置：

<httpProtocol>
      <customHeaders>
        <add name="Access-Control-Allow-Origin" value="*" />
        <add name="Access-Control-Allow-Headers" value="*" />
        <add name="Access-Control-Allow-Methods" value="GET, POST, PUT, DELETE" />
      </customHeaders>
    </httpProtocol>

方法2  设置 CORS

http://www.cnblogs.com/landeanfen/p/5177176.html