我返回引用字典,我只读属性。我如何prevent消费者改变我的数据?如果这是一个的IList
我可以简单地返回它 AsReadOnly
。是否有类似的东西我可以用一本字典吗?
私人_mydictionary作为词典(字符串,字符串)
公共只读属性MyDictionary()作为词典(字符串,字符串)
得到
返回_mydictionary
最终获取
高端物业
解决方案
下面是一个简单的实现,它封装了字典:
公共类ReadOnlyDictionary< TKEY的,TValue> :IDictionary的< TKEY的,TValue>
{
私人只读IDictionary的< TKEY的,TValue> _字典;
公共ReadOnlyDictionary()
{
_dictionary =新字典< TKEY的,TValue>();
}
公共ReadOnlyDictionary(IDictionary的< TKEY的,TValue>字典)
{
_dictionary =字典;
}
#地区的IDictionary< TKEY的,TValue>会员
无效的IDictionary< TKEY的,TValue>。新增(TKEY的关键,TValue值)
{
扔ReadOnlyException();
}
公共BOOL的containsKey(TKEY的键)
{
返回_dictionary.ContainsKey(键);
}
公众的ICollection< TKEY的>钥匙
{
{返回_dictionary.Keys; }
}
布尔的IDictionary< TKEY的,TValue>卸下摆臂(TKEY的键)
{
扔ReadOnlyException();
}
公共BOOL TryGetValue(TKEY的钥匙,走出TValue值)
{
返回_dictionary.TryGetValue(键,超时值);
}
公众的ICollection< TValue>值
{
{返回_dictionary.Values; }
}
公共TValue这[TKEY的关键]
{
得到
{
返回_dictionary [关键];
}
}
TValue IDictionary的< TKEY的,TValue>。这[TKEY的关键]
{
得到
{
返回此[关键];
}
组
{
扔ReadOnlyException();
}
}
#endregion
#地区的ICollection< KeyValuePair< TKEY的,TValue>>会员
无效的ICollection< KeyValuePair< TKEY的,TValue>>。新增(KeyValuePair< TKEY的,TValue>项目)
{
扔ReadOnlyException();
}
无效的ICollection< KeyValuePair< TKEY的,TValue>> .Clear()
{
扔ReadOnlyException();
}
公共BOOL包含(KeyValuePair< TKEY的,TValue>项目)
{
返回_dictionary.Contains(项目);
}
公共无效CopyTo从(KeyValuePair< TKEY的,TValue> []数组,诠释arrayIndex)
{
_dictionary.CopyTo(阵列,arrayIndex);
}
公众诠释计数
{
{返回_dictionary.Count; }
}
公共BOOL的IsReadOnly
{
获得{返回true; }
}
布尔的ICollection< KeyValuePair< TKEY的,TValue>>卸下摆臂(KeyValuePair< TKEY的,TValue>项目)
{
扔ReadOnlyException();
}
#endregion
#地区的IEnumerable< KeyValuePair< TKEY的,TValue>>会员
公众的IEnumerator< KeyValuePair< TKEY的,TValue>>的GetEnumerator()
{
返回_dictionary.GetEnumerator();
}
#endregion
#地区IEnumerable的成员
IEnumerator的IEnumerable.GetEnumerator()
{
返回的GetEnumerator();
}
#endregion
私有静态异常ReadOnlyException()
{
返回新NotSupportedException异常(这本词典是只读);
}
}
I'm returning a reference to a dictionary in my read only property. How do I prevent consumers from changing my data? If this were an IList
I could simply return it AsReadOnly
. Is there something similar I can do with a dictionary?
Private _mydictionary As Dictionary(Of String, String)
Public ReadOnly Property MyDictionary() As Dictionary(Of String, String)
Get
Return _mydictionary
End Get
End Property
解决方案
Here's a simple implementation that wraps a dictionary :
public class ReadOnlyDictionary<TKey, TValue> : IDictionary<TKey, TValue>
{
private readonly IDictionary<TKey, TValue> _dictionary;
public ReadOnlyDictionary()
{
_dictionary = new Dictionary<TKey, TValue>();
}
public ReadOnlyDictionary(IDictionary<TKey, TValue> dictionary)
{
_dictionary = dictionary;
}
#region IDictionary<TKey,TValue> Members
void IDictionary<TKey, TValue>.Add(TKey key, TValue value)
{
throw ReadOnlyException();
}
public bool ContainsKey(TKey key)
{
return _dictionary.ContainsKey(key);
}
public ICollection<TKey> Keys
{
get { return _dictionary.Keys; }
}
bool IDictionary<TKey, TValue>.Remove(TKey key)
{
throw ReadOnlyException();
}
public bool TryGetValue(TKey key, out TValue value)
{
return _dictionary.TryGetValue(key, out value);
}
public ICollection<TValue> Values
{
get { return _dictionary.Values; }
}
public TValue this[TKey key]
{
get
{
return _dictionary[key];
}
}
TValue IDictionary<TKey, TValue>.this[TKey key]
{
get
{
return this[key];
}
set
{
throw ReadOnlyException();
}
}
#endregion
#region ICollection<KeyValuePair<TKey,TValue>> Members
void ICollection<KeyValuePair<TKey, TValue>>.Add(KeyValuePair<TKey, TValue> item)
{
throw ReadOnlyException();
}
void ICollection<KeyValuePair<TKey, TValue>>.Clear()
{
throw ReadOnlyException();
}
public bool Contains(KeyValuePair<TKey, TValue> item)
{
return _dictionary.Contains(item);
}
public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
{
_dictionary.CopyTo(array, arrayIndex);
}
public int Count
{
get { return _dictionary.Count; }
}
public bool IsReadOnly
{
get { return true; }
}
bool ICollection<KeyValuePair<TKey, TValue>>.Remove(KeyValuePair<TKey, TValue> item)
{
throw ReadOnlyException();
}
#endregion
#region IEnumerable<KeyValuePair<TKey,TValue>> Members
public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
{
return _dictionary.GetEnumerator();
}
#endregion
#region IEnumerable Members
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
#endregion
private static Exception ReadOnlyException()
{
return new NotSupportedException("This dictionary is read-only");
}
}