asp.net – 为什么这个JSON返回“无效的JSON原语”？

这个初始JSON来自服务器和IS VALID：

{
    "AppropriationAmount": 25000000,"AppropriationHours": 56300,"ArrThreshold": 11,"ClientKey": 24,"Description": 'Find and incarcerate the escaped prisoner',"DirectHours": 50000,"EndDate": '3/31/2011',"EngineeringHours": 4000,"IndirectHours": 2000,"Key": 1589,"Number": '0',"OtherHours": 300,"ProductivityCurveType": 'BurnedEarned',"ProjectManager": 'Doctor Who',"ProjectName": 'Prisoner ZERO',"StartDate": '5/1/2010' 
    }

这个后续的JSON发送到服务器FAILS：
一旦用户编辑了表单,数据就会被客户端序列化并发送回来……然后在尝试反序列化JSON时失败.

{
    "AppropriationAmount": 56300.00,"AppropriationHours": 25000000.00,"ArrThreshold": 11.00,"ClientKey":,"DirectHours": 50000.00,"EngineeringHours": 4000.00,"IndirectHours": 2000.00,"OtherHours": 300.00,"StartDate": '5/1/2010' 
    }

此代码抛出错误：

try
    {
        if (!String.IsNullOrEmpty(this.JSON))
        {
            serializer = new JavaScriptSerializer();
            dialog = serializer.Deserialize<ProjectDecorator>(this.JSON);
        }
    }
    catch (Exception ex)
    {
        // The message shows here
    }

抛出的错误看起来像：

{"Invalid JSON primitive: ."}