需要在Global.asax的Application中进行初始化处理 这样：GlobalConfiguration.Configuration.MessageHandlers.Add(new DefaultHandler())


然后在App_Start文件夹中添加 DefaultHandler 类复制下面的代码

public class DefaultHandler : DelegatingHandler

{

protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)

{

request.RequestUri = new Uri(request.RequestUri.ToString());

MediaTypeHeaderValue contentType = request.Content.Headers.ContentType;

if (contentType != null)

{

switch (contentType.MediaType)

{

case "application/x-www-form-urlencoded":

{

NameValueCollection formData = await request.Content.ReadAsFormDataAsync(cancellationToken);

request.Content = new FormUrlEncodedContent(Correct(formData));

//如下代码为了预下订单使用

var formDataDic = formData.ToDictionary();

var str = ConvertToJsonString(formDataDic);

HttpContext.Current.Request.Headers.Add("formDataToJson", str);

}

break;

case "multipart/form-data":

{

NameValueCollection formData = await request.Content.ReadAsFormDataAsync(cancellationToken);

request.Content = new FormUrlEncodedContent(Correct(formData));

}

break;

case "application/json":

{

HttpContentHeaders oldHeaders = request.Content.Headers;

string formData = await request.Content.ReadAsStringAsync();

request.Content = new StringContent(formData);

ReplaceHeaders(request.Content.Headers, oldHeaders);

}

break;

default:

throw new Exception("Implement It!");

}

}

return await base.SendAsync(request, cancellationToken);

}

private static IEnumerable<KeyValuePair<string, string>> Correct(NameValueCollection formData)

{

return formData.Keys.Cast<string>().Select(key => new KeyValuePair<string, string>(key, formData[key])).ToList();

}

private static void ReplaceHeaders(HttpHeaders currentHeaders, HttpHeaders oldHeaders)

{

currentHeaders.Clear();

foreach (var item in oldHeaders)

currentHeaders.Add(item.Key, item.Value);

}

private string ConvertToJsonString(IDictionary<string, string> param)

{

dynamic myObj = new ExpandoObject();

var dic = (IDictionary<string, object>)myObj;

foreach (var item in param)

{

if (item.Value.StartsWith("[") || item.Value.StartsWith("{"))

{

dic[item.Key] = JsonConvert.DeserializeObject(item.Value);

}

else

{

dic[item.Key] = item.Value;

}

}

return JsonConvert.SerializeObject(myObj);

}

}

public static class NVCExtender

{

public static IDictionary<string, string> ToDictionary(this NameValueCollection source)

{

return source.AllKeys.ToDictionary(k => k, k => source[k]);

}

}