C# program to merge two Dictionaries

Set the two dictionaries −

Dictionary < string, int > dict1 = new Dictionary < string, int > ();
dict1.Add("laptop", 1);
dict1.Add("desktop", 2);
Dictionary < string, int > dict2 = new Dictionary < string, int > ();
dict2.Add("desktop", 3);
dict2.Add("tablet", 4);
dict2.Add("mobile", 5);

Now use HashSet and UnionWith() method to merge the two dictionaries −

HashSet < string > hSet = new HashSet < string > (dict1.Keys);
hSet.UnionWith(dict2.Keys);

Here is the complete code −

Example

using System;
using System.Collections.Generic;
class Program {
   static void Main() {
      Dictionary < string, int > dict1 = new Dictionary < string, int > ();
      dict1.Add("laptop", 1);
      dict1.Add("desktop", 2);

      Dictionary < string, int > dict2 = new Dictionary < string, int > ();
      dict2.Add("desktop", 3);
      dict2.Add("tablet", 4);
      dict2.Add("mobile", 5);

      HashSet < string > hSet = new HashSet < string > (dict1.Keys);
      hSet.UnionWith(dict2.Keys);
      Console.WriteLine("Merged Dictionary...");

      foreach(string val in hSet) {
         Console.WriteLine(val);
      }
   }
}