这段代码是线程安全的吗？如果没有,我怎样才能使它成为线程安全的？

public class Page
{
    public string Name {get; set; }
}
 
public class PageQueue
{
    private ConcurrentDictionary<int,ConcurrentQueue<Page>> pages =
        new ConcurrentDictionary<int,ConcurrentQueue<Page>>();
 
    public void Add(int id,Page page)
    {
        if (!this.pages.ContainsKey(id))
            this.pages[id] = new ConcurrentQueue<Page>();
 
        this.pages[id].Enqueue(page);
    }
 
    public Page GetAndRemove(int id)
    {
        Page lp = null;
 
        if(this.pages.ContainsKey(id))
            this.pages[id].TryDequeue(out lp);
 
        return lp;
    }
}

演示：

public class Demo
 {
     public void RunAll()
     {
         for (int i = 0; i < 10; i++)
             Task.Factory.StartNew(() => Run());
     }
 
     public void Run()
     {
         PageQueue pq = new PageQueue();
         pq.Add(1,new Page());
 
         pq.GetAndRemove(1);
     }
 }