mvc3中的十进制错误——该值对字段无效

I'm following [Getting started with ASP.NET MVC 3][1]. And I can't add/edit with value of Price = 9.99 or 9,99. It said: "The value '9.99' is not valid for Price." and "The field Price must be a number."I'm following [Getting started with ASP.NET MVC