对于EF4属性类型，使用一个struct代替原语

I've got an EF4 entity (code-first) that includes an int bitmask. I've created a Bitmask struct to make working with bitmasks easier (provides bool properties to access the bits). The bitmask struct includes overloaded implicit operators for converting to and from an int. I've got an EF4 entity (code-first) that includ