Review first, Use at your own risk

CommonDictionaryParser.cs

    public class CommonDictionaryParser {
        public CommonDictionaryParser(string dict) {
            DictionaryString = dict;
            ParseToDictionary();
        }
        public CommonDictionaryParser(Dictionary<string, string> dict) {
            Dictionary = dict;
        }
        public string DictionaryString;
        public Dictionary<string, string> Dictionary;

        public char PairSeparator = ';';
        public char KeySeparator = '=';
        public void ParseToDictionary() {
            Dictionary = new Dictionary<string, string>();
            if (string.IsNullOrEmpty(DictionaryString) || DictionaryString.Length < 5) return;
            var key = new StringBuilder();
            var value = new StringBuilder();
            var status = 0; // 0=key, 1=keyseparator, 2=value, 3=pairseparator
            for (var i = 0; i < DictionaryString.Length; i++) {
                var currentChar = DictionaryString[i];
                switch (status) {
                    case 0:
                        key.Append(currentChar);
                        if (i + 1 < DictionaryString.Length && DictionaryString[i + 1] == KeySeparator) {
                            status = 1;
                        }
                        break;
                    case 1:
                        status = 2;
                        break;
                    case 2:
                        value.Append(currentChar);
                        if (i + 1 < DictionaryString.Length && DictionaryString[i + 1] == PairSeparator) {
                            status = 3;
                            Dictionary.Add(key.ToString(), value.ToString());
                            key = new StringBuilder();
                            value = new StringBuilder();
                        }
                        else if (i + 1 == DictionaryString.Length) {
                            status = 3;
                            Dictionary.Add(key.ToString(), value.ToString());
                            key = new StringBuilder();
                            value = new StringBuilder();
                        }
                        break;
                    case 3:
                        status = 0;
                        break;
                }
            }
        }
        public new string ToString() {
            return string.Join(PairSeparator.ToString(), Dictionary.Select(x => x.Key + KeySeparator + x.Value));
        }
    }