C# multiple key/value pairs of various types in a single line of code...?

How about using a Dictionary With that you provide a KeyName (string) and and object of any type.

Something like ...

 Dictionary<string, object> Parameters = new Dictionary<string, object>();
 Parameters.Add("Key1", "A string");
 Parameters.Add("Key2", true);
 Parameters.Add("Key3", 42);

The above should create a dictionary holding a string, a bool and an int.

They can be referenced like ...

 string a = Parameters["Key1"] as string;
 bool? b = Parameters["Key2"] as bool?;
 int? c = Parameters["Key3"] as int?;

I believe this will accomplish what you are wanting.

Hope it helps,
-Larry