如何将observablecollection放入列表

你好
我想将observablecollection放入List< string>像这样:

Hello
I want to put observablecollection into the List<string> like this :

<pre lang="cs">List<string> test = new List<string>();<br />
          foreach (CheckInData coll in CheckInCollection)<br />
          {<br />
              for (int i = 0; i < _CheckInCollection.Count; i++)<br />
              {<br />
               test.Add(coll.RoomNumber[i].ToString());<br />
              }<br />
              <br />
          }</pre><br />

但它仅将集合的第一个字符作为示例，例如，有2424个测试内容将仅为2个.
请任何人帮助我

这是我的收藏集:

but its only put the first character of collection for example there is 2424 test content will be only 2.
Please help me anybody

This is my Collection:

<pre lang="cs">ObservableCollection<CheckInData> _CheckInCollection = new ObservableCollection<CheckInData>();<br />
<br />
   public ObservableCollection<CheckInData> CheckInCollection<br />
   {<br />
       get { return _CheckInCollection; }<br />
   }<br />
   public class CheckInData<br />
   {<br />
       public string RoomNumber { get; set; }<br />
       public decimal Price { get; set; }<br />
       public string Currecny { get; set; }<br />
       public decimal Discount { get; set; }<br />
       public string CheckOut { get; set; }<br />
       public int TotalDay { get; set; }<br />
       public decimal TotalPrice { get; set; }<br />
       public int CheckOutYear { get; set; }<br />
       public int CheckOutMonth { get; set; }<br />
       public int CheckOutDay { get; set; }<br />
       public Boolean IncToday { get; set; }<br />
   }</pre><br />