在构造函数中初始化静态字段.这是正常的？

Question

public class SharedCacheData : ISharedCacheData
{
    private readonly ISharedPetsService mPetsService;
    private static ISharedEmployeeService mSharedEmployeeService;
 public SharedCacheData(ISharedPetsService petsService, ISharedEmployeeService employeeService)
    {
        mPetsService = petsService;
        mSharedEmployeeService = employeeService;
    }

    public static string GetUserFullName(string key)
    {
        Hashtable value = HttpContext.Current.Application[USERFULLNAME_KEY] as Hashtable;
        if (value == null)
        {
            value = new Hashtable();
            HttpContext.Current.Application[USERFULLNAME_KEY] = value;
        }
        if (value.ContainsKey(key))
            return value[key] as string;

        string name = mSharedEmployeeService.FindOneUser(key);
        value[key] = name;
        return name;
    }

是否在构造函数中初始化静态字段mSharedEmployeeService(service)？

Answer 1

不,这通常是一个坏主意.每次创建新实例时,它都将替换静态变量.这几乎肯定不是你想要做的.

我不知道是否确实这里应该有两个类-一个用于宠物的服务和一个为员工服务.从提供的代码中很难说出来,但我们在这里看到的并不是一个好主意.

Answer 2

在静态构造函数中初始化它会更有意义:

http://msdn.microsoft.com/en-us/library/k9x6w0hc(v=vs.80).aspx

class SimpleClass
{
    // Static constructor
    static SimpleClass()
    {
        //...
    }
}