为什么我不能在wcf服务中使用Newtonsoft.Json JsonConvert.SerializeObject？

Question

I am using Newtonsoft.Json dll for Serialize object to return string from wcf service. When I call other simple method from service it works fine but when I call method which serialize object into string and return that string its not working. Below is my code of service.

public string GetString()
    {
        return "Hello";
    }

    public string GetData(int i)
    {
        My_Entities ME = new MY_Entities();

        ApplicationVM oVM = new ApplicationVM()
        {
            AP_M_BloodGroup = ME.AP_M_BloodGroup.ToList().ElementAtOrDefault(i),
            AP_M_DayMaster = ME.AP_M_DayMaster.ToList().ElementAtOrDefault(i)
        };
        return JsonConvert.SerializeObject(oVM, Formatting.Indented);
    }

Both method work for local but after hosting when calling GetData() method it will give error message "Access Denied" at client side. So, what is the problem and what I need to put extra?

When I put client side code in try-catch block it gives message like:

Message: Request for the permission of type 'System.Security.Permissions.SecurityPermission, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed

Answer 1

I use

<trust level="Full" />

under system.web in web.config as per @d_Z suggested and it works.