How to cut up a string from an input file with Regex or String Split, C#?

here’s a start:

string date;
string subject;
string from;
string read;
string to;

foreach (string line in myString.Split(new string[] { Environment.NewLine }, StringSplitOptions.None))
{
    if(line.Contains("Subject="))
         subject = line;
    else if (line.Contains("From="))
         from = line;

    //......
}