Merging dictionaries in C#

Question

What\'s the best way to merge 2 or more dictionaries (Dictionary) in C#? (3.0 features like LINQ are fine).

I\'m thinking of a method signa

Answer 1

Based on the answers above, but adding a Func-parameter to let the caller handle the duplicates:

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

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