c# - PowerCollections - MultiDictionary 'Remove' 在找不到值时删除所有值

Question

我正在使用来自 http://powercollections.codeplex.com/ 的 powercollections 库

第一个测试通过，但第二个测试失败。如果找不到值，我不希望 Remove 从字典中删除所有项目。

这是个问题还是我误解了 Remove 的功能？

[Test]
public void passing_test()
{
    var classes = new MultiDictionary<string, object>(false);
    classes.Add("class", "class_name1");
    classes.Add("class", "class_name2");
    classes.Remove("class", "class_name2");

    Assert.AreEqual(1, classes.Count);
}

[Test]
public void failing_test()
{
    var classes = new MultiDictionary<string, object>(false);
    classes.Add("class", "class_name1");
    classes.Remove("class", "class_name2");

    Assert.AreEqual(1, classes.Count);
}

Answer 1

它实际上看起来像是代码中的错误:

        /// <summary>
        /// Removes a given value from the values associated with a key. If the
        /// last value is removed from a key, the key is removed also.
        /// </summary>
        /// <param name="key">A key to remove a value from.</param>
        /// <param name="value">The value to remove.</param>
        /// <returns>True if <paramref name="value"/> was associated with <paramref name="key"/> (and was
        /// therefore removed). False if <paramref name="value"/> was not associated with <paramref name="key"/>.</returns>
        public sealed override bool Remove(TKey key, TValue value)
        {
            KeyAndValues keyValues = new KeyAndValues(key);
            KeyAndValues existing;

            if (hash.Find(keyValues, false, out existing)) {
                // There is an item in the hash table equal to this key. Find the value.
                int existingCount = existing.Count;
                int valueHash = Util.GetHashCode(value, valueEqualityComparer);
                int indexFound = -1;
                for (int i = 0; i < existingCount; ++i) {
                    if (Util.GetHashCode(existing.Values[i], valueEqualityComparer) == valueHash &&
                        valueEqualityComparer.Equals(existing.Values[i], value)) 
                    {
                        // Found an equal existing value
                        indexFound = i;
                    }
                }

                if (existingCount == 1) {
                    // Removing the last value. Remove the key.
                    hash.Delete(existing, out keyValues);
                    return true;
                }

请注意他们是如何检查 existingCount == 1 的？尽管您输入的值不同，但没有代码检查在 hash.Delete 调用之前的搜索中是否找到索引。解决此问题的正确方法是执行以下操作:

            if (existingCount == 1 && indexFound != -1) {
                // Removing the last value. Remove the key.
                hash.Delete(existing, out keyValues);
                return true;
            }

这是完整的来源:http://powercollections.codeplex.com/SourceControl/changeset/view/6259#71508