看一下Phil Haack关于模型绑定JSON数据的文章。问题是默认模型联编程序无法正确序列化JSON。您需要某种ValueProvider或可以编写自定义模型绑定程序：
using System.IO;using System.Web.script.Serialization;public class JsonModelBinder : DefaultModelBinder { public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext) { if(!IsJSonRequest(controllerContext)) { return base.BindModel(controllerContext, bindingContext); } // Get the JSON data that's been posted var request = controllerContext.HttpContext.Request; //in some setups there is something that already reads the input stream if content type = 'application/json', so seek to the begining request.InputStream.Seek(0, SeekOrigin.Begin); var jsonStringData = new StreamReader(request.InputStream).ReadToEnd(); // Use the built-in serializer to do the work for us return new JavascriptSerializer() .Deserialize(jsonStringData, bindingContext.Modelmetadata.ModelType); // -- REQUIRES .NET4 // If you want to use the .NET4 version of this, change the target framework and uncomment the line below // and comment out the above return statement //return new JavascriptSerializer().Deserialize(jsonStringData, bindingContext.Modelmetadata.ModelType); } private static bool IsJSonRequest(ControllerContext controllerContext) { var contentType = controllerContext.HttpContext.Request.ContentType; return contentType.Contains("application/json"); } }public static class JavascriptSerializerExt { public static object Deserialize(this JavascriptSerializer serializer, string input, Type objType) { var deserializerMethod = serializer.GetType().GetMethod("Deserialize", BindingFlags.NonPublic | BindingFlags.Static); // internal static method to do the work for us //Deserialize(this, input, null, this.RecursionLimit); return deserializerMethod.Invoke(serializer, new object[] { serializer, input, objType, serializer.RecursionLimit }); } }并告诉MVC在您的Global.asax文件中使用它：
ModelBinders.Binders.DefaultBinder = new JsonModelBinder();
另外，此代码利用了内容类型=’application / json’，因此请确保您在jquery中进行设置，如下所示：
$.ajax({ dataType: "json", contentType: "application/json", type: 'POST', url: '/Controller/Action', data: { 'items': JSON.stringify(lineItems), 'id': documentId }});
