using System;
using System.Text.RegularExpressions;
 
public class Test
{
	public static void Main()
	{
        string pattern = @",(?=[^}]*(?:,|$))";
        string input = @"""Key1""=123,""Key2""=""abc"",""key3""={""subkey1""=12,""subkey2""=""cd""},""key4""=456";
 
      string[] result = Regex.Split(input, pattern, 
                                    RegexOptions.IgnoreCase,
                                    TimeSpan.FromMilliseconds(500));
      for (int ctr = 0; ctr < result.Length; ctr++) 
      {
         Console.WriteLine("'{0}'", result[ctr]);
 
      }
	}
}

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