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

using System.Collections.Generic;
using System.Linq;

public static class DictionaryExtensions
{
    public enum MergeKind { SkipDuplicates, OverwriteDuplicates }
    public static void Merge(this IDictionary target, IDictionary source, MergeKind kind = MergeKind.SkipDuplicates) =>
        source.ToList().ForEach(_ => { if (kind == MergeKind.OverwriteDuplicates || !target.ContainsKey(_.Key)) target[_.Key] = _.Value; });
}

You can either skip/ignore (default) or overwrite the duplicates: And Bob's your uncle provided you are not overly fussy about Linq performance but prefer instead concise maintainable code as I do: in which case you can remove the default MergeKind.SkipDuplicates to enforce a choice for the caller and make the developer cognisant of what the results will be!