const string input = "\"key\"=\"value\";\"key1\"=\"value1\";\"key2\"=\"value2\"";
var result = Regex.Matches(input, @"\""(?<key>\w*)\""=\""(?<value>\w*)\""")
.OfType<Match>()
.ToDictionary(match => match.Groups["key"], match => match.Groups["value"]);
foreach (var pair in result) {
Console.Write(pair.Key);
Console.Write("=");
Console.WriteLine(pair.Value);
}