/// <summary>
/// GetOneByValue 从字典中找出第一个值与val相等的记录的key
/// </summary>
public static TKey GetOneByValue<TKey, TValue>(IDictionary<TKey, TValue> dic, TValue val)
where TKey : class
where TValue : IEquatable<TValue>
{
return CollectionHelper.FindFirstSpecification<TKey>(dic.Keys, delegate(TKey cur) { return dic[cur].Equals(val); });
}
/// <summary>
/// ConvertSpecification 将source中的符合predicate条件的第一个元素转换为TResult类型
/// </summary>
public static TResult ConvertFirstSpecification <TObject, TResult>(IEnumerable <TObject> source, Func <TObject, TResult> converter, Predicate <TObject> predicate)
{
TObject target = CollectionHelper.FindFirstSpecification <TObject>(source, predicate);
if (target == null)
{
return(default(TResult));
}
return(converter(target));
}