Dictionary 進行where的枚舉遍歷

 Dictionary<int, string>進行枚舉遍歷的時候，使用IEnumerable<KeyValuePair<TKey, TValue>>.當然完全可以用foreach遍歷，foreach把枚舉的復雜性降低了。

 public static Dictionary<int, string> listPartition;
 IEnumerable<KeyValuePair<int, string>> partitiontemp = listPartition.Where(c => (!string.IsNullOrEmpty(province) ? c.Value.Trim().Contains(province) : true || !string.IsNullOrEmpty(ownCity) ? c.Value.Trim().Contains(ownCity) : true));
            if (partitiontemp!=null)
            {
                partition = partitiontemp.First().Key;
            }

[SerializableAttribute]
[ComVisibleAttribute(false)]
public class Dictionary<TKey, TValue> : IDictionary<TKey, TValue>, 
ICollection<KeyValuePair<TKey, TValue>>, IDictionary, ICollection, 
IReadOnlyDictionary<TKey, TValue>, IReadOnlyCollection<KeyValuePair<TKey, TValue>>, 
IEnumerable<KeyValuePair<TKey, TValue>>, IEnumerable, ISerializable, 
IDeserializationCallback