using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string partData=@"partNum = XYZ

​

qty = 123

​

wght = 14

​

len = 60";

        for (Match match = Regex.Match(partData, @"^\s*([^=]+?)\s*=\s*(.*?)\s*$", RegexOptions.Multiline); 

                match.Success;

                match = match.NextMatch()) {

            // this code runs for each line in your string which has the expected pattern

            string key = match.Groups[1].Value;

            string value = match.Groups[2].Value;

                    Console.WriteLine("key:"+key+" | value:"+value);

        }

    }

}