比较2 Dictionary <string,string> Instances

Question

我想比较两个Dictionary<string, string>实例的内容,无论它们包含的项目的顺序如何. SequenceEquals还比较了顺序,所以我首先按键排序字典,然后调用SequenceEquals.

有没有我可以使用的方法而不是SequenceEquals只比较内容？

如果没有,这是理想的方法吗？

Dictionary<string, string> source = new Dictionary<string, string>();
Dictionary<string, string> target = new Dictionary<string, string>();

source["foo"] = "bar";
source["baz"] = "zed";
source["blah"] = null;

target["baz"] = "zed";
target["blah"] = null;
target["foo"] = "bar";

// sequenceEquals will be false
var sequenceEqual = source.SequenceEqual(target);
// contentsEqual will be true
var contentsEqual = source.OrderBy(x => x.Key).SequenceEqual(target.OrderBy(x => x.Key));

Answer 1

var contentsEqual = source.DictionaryEqual(target);

// ...

public static bool DictionaryEqual<TKey, TValue>(
    this IDictionary<TKey, TValue> first, IDictionary<TKey, TValue> second)
{
    return first.DictionaryEqual(second, null);
}

public static bool DictionaryEqual<TKey, TValue>(
    this IDictionary<TKey, TValue> first, IDictionary<TKey, TValue> second,
    IEqualityComparer<TValue> valueComparer)
{
    if (first == second) return true;
    if ((first == null) || (second == null)) return false;
    if (first.Count != second.Count) return false;

    valueComparer = valueComparer ?? EqualityComparer<TValue>.Default;

    foreach (var kvp in first)
    {
        TValue secondValue;
        if (!second.TryGetValue(kvp.Key, out secondValue)) return false;
        if (!valueComparer.Equals(kvp.Value, secondValue)) return false;
    }
    return true;
}

Answer 2

我不知道是否有一个现有的方法但你可以使用以下(为了简洁省略了args的空检查)

public static bool DictionaryEquals<TKey,TValue>(
  this Dictionary<TKey,TValue> left,
  Dictionary<TKey,TValue> right ) { 

  var comp = EqualityComparer<TValue>.Default;
  if ( left.Count != right.Count ) { 
    return false;
  }
  foreach ( var pair in left ) {
    TValue value;
    if ( !right.TryGetValue(pair.Key, out value) 
         || !comp.Equals(pair.Value, value) ) {
      return false;
    }
  } 
  return true;
}

最好添加一个重载以允许自定义EqualityComparer<TValue>.