互锁,反射值类型增量

我想使用interlocked.increment增加一个对象的整数成员,但是我想通过反射引用这些整数。下面是我所拥有的不起作用的示例代码。

public class StatBoard
{

    #region States (count of)
    public int Active;
    public int Contacting;
    public int Polling;
    public int Connected;
    public int Waiting;
    public int Idle;
    #endregion

    protected IEnumerable<FieldInfo> states;

    public StatBoard()
    {
        Type foo = GetType();
        FieldInfo[] fields = foo.GetFields(BindingFlags.Instance & BindingFlags.Public);

        states = from n in fields
                     where n.FieldType == typeof(int)
                     select n;

    }

    public void UpdateState(string key)
    {
        FieldInfo statusType = states.First( 
            i => i.Name == key
        );

        System.Threading.Interlocked.Increment(ref (int)statusType.GetValue(this));
    }

}

如何修改updateState方法以使其正常工作?