如下代码
public interface ISingalrSvc
{
}

public class SingalrSvc : ISingalrSvc
{
    private static ConcurrentDictionary<string, string> connectionMaps = new ConcurrentDictionary<string, string>();
  
    public void SetConnectionMaps(string connectionId, string value)
    {
        connectionMaps.AddOrUpdate(connectionId, value, (connectionId, value) => { return connectionId; });
    }
}

然后另一个类使用的时候通过构造函数注入，
public class SingalrService : Hub<ISingalrClient>
{
private ISingalrSvc _singalrSvc;
public SingalrService(ISingalrSvc singalrSvc)
{
_singalrSvc = singalrSvc;
}

    public void SetConnectionMaps(string account)
    {
        string connectionid = Context.ConnectionId;
        _singalrSvc.SetConnectionMaps(connectionid, account);
    }

}

为什么每次页面加载运行SetConnectionMaps的方法时，connectionMaps 就会变为0，静态变量不是全局唯一的，不属于类的吗？