使用json.net 出现“操作可能会破坏运行时稳定性”，未处理 System.Security.VerificationException

悬赏园豆：10 [待解决问题]

win8x64 ,vs2010,Framworkv4.0；

代码：

[DataContract]
public class User
{
[DataMember(Order=0,IsRequired=true)]
public string name { get; set; }
[DataMember(Order=1)]
public string email { get; set; }
[DataMember(Order = 2)]
public string address { get; set; }
[DataMember(Order = 3)]
public string sex { get; set; }
}

private void button1_Click(object sender, EventArgs e)

{

User user=new User{

name=textBox1.Text,

email=textBox2.Text,

address=textBox3.Text,

sex=radioButton1.Checked?"男":"女"

};

var json = JsonConvert.SerializeObject(user);

。。。。

错误堆栈：

未处理 System.Security.VerificationException

HResult=-2146233075

Message=操作可能会破坏运行时稳定性。

Source=Newtonsoft.Json

StackTrace:

在 Newtonsoft.Json.Serialization.DefaultContractResolver.SetPropertySettingsFromAttributes(JsonProperty property, Object attributeProvider, String name, Type declaringType, MemberSerialization memberSerialization, Boolean& allowNonPublicAccess)

在 Newtonsoft.Json.Serialization.DefaultContractResolver.CreateProperty(MemberInfo member, MemberSerialization memberSerialization)

在 Newtonsoft.Json.Serialization.DefaultContractResolver.CreateProperties(Type type, MemberSerialization memberSerialization)

在 Newtonsoft.Json.Serialization.DefaultContractResolver.CreateObjectContract(Type objectType)

在 Newtonsoft.Json.Serialization.DefaultContractResolver.CreateContract(Type objectType)

。。。

问题补充：

在另外一个项目中出现类似的问题。
代码：

using Couchbase;
using Couchbase.Extensions;
using Enyim.Caching.Memcached;
using Couchbase.Configuration;

//读配置文件的方式创建client
[System.Security.Permissions.PermissionSet(System.Security.Permissions.SecurityAction.Assert)]
private static void NewMethod1()
{
var client = CouchbaseManager.Instance;
var key = "cottrell_brewing-old_yankee_ale";
var newBeer = new Beer
{
Name = "Old Yankee Ale",
abv = 5.00f,
BreweryId = "cottrell_brewing",
Style = "American-Style Amber",
Category = "North American Ale"
};
var result = client.StoreJson(StoreMode.Add, key, newBeer);
if (result)
{
var savedBeer = client.GetJson<Beer>(key);
Console.WriteLine("Found beer:" + savedBeer.Name);
}
}