locking static variable

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static

Hi,

I have a following class at server-side.

public class Sample
{
    private enum Status
    {
        NotEvaluated,
        Yes,
        No
    }
    private static object _lockObj = new object();
    private static Status _status = Status.NotEvaluated;
    public static Status GetStatus()
    {
        if (_status == Status.NotEvaluated)
        {
            lock (_lockObj)
            {
                if (_status == Status.NotEvaluated)
                {
                    //some evaluation code which sets status to either Yes/No;
                    _status = Status.Yes;
                }
            }
        }
        return _status;
    }
}

Is anything wrong in locking mechanism above? do i need to lock at all? Because it is server-side (multiple requests will be there) and the variable is static i would think it should be locked at the time of evaluation.

correct me if i am wrong.

Thanks