其平凡解为:

using System.Collections.Generic;
...
public static Dictionary<TKey, TValue>
    Merge<TKey,TValue>(IEnumerable<Dictionary<TKey, TValue>> dictionaries)
{
    var result = new Dictionary<TKey, TValue>();
    foreach (var dict in dictionaries)
        foreach (var x in dict)
            result[x.Key] = x.Value;
    return result;
}

基于上面的答案，但添加一个Func-parameter，让调用者处理重复:

public static Dictionary<TKey, TValue> Merge<TKey, TValue>(this IEnumerable<Dictionary<TKey, TValue>> dicts, 
                                                           Func<IGrouping<TKey, TValue>, TValue> resolveDuplicates)
{
    if (resolveDuplicates == null)
        resolveDuplicates = new Func<IGrouping<TKey, TValue>, TValue>(group => group.First());

    return dicts.SelectMany<Dictionary<TKey, TValue>, KeyValuePair<TKey, TValue>>(dict => dict)
                .ToLookup(pair => pair.Key, pair => pair.Value)
                .ToDictionary(group => group.Key, group => resolveDuplicates(group));
}

Dictionary<String, String> allTables = new Dictionary<String, String>();
allTables = tables1.Union(tables2).ToDictionary(pair => pair.Key, pair => pair.Value);

注意，如果你使用一个名为“Add”的扩展方法，你可以使用集合初始化器来组合尽可能多的字典，就像这样:

public static void Add<K, V>(this Dictionary<K, V> d, Dictionary<K, V> other) {
  foreach (var kvp in other)
  {
    if (!d.ContainsKey(kvp.Key))
    {
      d.Add(kvp.Key, kvp.Value);
    }
  }
}


var s0 = new Dictionary<string, string> {
  { "A", "X"}
};
var s1 = new Dictionary<string, string> {
  { "A", "X" },
  { "B", "Y" }
};
// Combine as many dictionaries and key pairs as needed
var a = new Dictionary<string, string> {
  s0, s1, s0, s1, s1, { "C", "Z" }
};

这是我的解决方案:它的行为类似于python中的dict.update()方法。

public static class DictionaryExtensions
{
    public static void Update<K,V>(this IDictionary<K, V> me, IDictionary<K, V> other)
    {
        foreach (var x in other)
        {
            me[x.Key] = x.Value;
        }
    }
}

试试

namespace Extensions
{
    public static class DictionaryExtensions
    {
        public static Dictionary<T, Y> MergeWith<T, Y>(this Dictionary<T, Y> dictA,
            Dictionary<T, Y> dictB)
        {
            foreach (var item in dictB)
            {
                if (dictA.ContainsKey(item.Key))
                    dictA[item.Key] = item.Value;
                else
                    dictA.Add(item.Key, item.Value);
            }
            return dictA;
        }
    }
}

当你想合并两个字典时

    var d1 = new Dictionary<string, string>();
    var d2 = new Dictionary<string, string>();
    d1.MergeWith(d2);