leetcode3:Longest Substring Without Repeating Characters

public int LengthOfLongestSubstring(string s) {
        Queue<char> queue=new Queue<char>();
		 	int max=0;
		 	for(int i=0;i<s.Length;i++)
		 	{
		 		if(queue.Contains(s[i]))
		 		{
		 			max=Math.Max(max,queue.Count);
		 			while(queue.Dequeue()!=s[i])
		 			{
		 				
		 			}
		 			//queue.Dequeue();
		 		}
		 		queue.Enqueue(s[i]);
		 	}
		 	return Math.Max(max,queue.Count);
    }