Extract substring from a string until finds a comma

You can use IndexOf() to find out where is the comma, and then extract the substring. If you are sure it will always have the comma you can skip the check.

        string a = "asdkjafjksdlfm,dsklfmdkslfmdkslmfksd";
        int comma = a.IndexOf(',');
        string b = a;
        if (comma != -1)
        {
            b = a.Substring(0, comma);
        }
        Console.WriteLine(b);

myString = myString.Substring(0,myString.IndexOf(','));