C# 更新cookies的方法

开发中经常遇到cookies更新的方法，以下方法为传入旧cookies和新cookies，自动合并更新为新的cookies，旧cookies和新cookies中的相同参数将会被新cookies的值给覆盖。

public static string updateCookie(string oldcookie, string newcookie)
{
    List<string> oldcookielist = new List<string>();
    if (oldcookie.Contains(";"))
        oldcookielist = new List<string>(oldcookie.Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries));
    else
        oldcookielist.Add(oldcookie);
    List<string> newcookielist = new List<string>();
    if (newcookie.Contains(";"))
        newcookielist = new List<string>(newcookie.Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries));
    else
        newcookielist.Add(newcookie);
    foreach (string cookie in newcookielist)
    {
        if (!string.IsNullOrWhiteSpace(cookie))
        {
            if (!string.IsNullOrWhiteSpace(cookie.Split('=')[1]))
            {
                bool isFind = false;
                for (int i = 0; i < oldcookielist.Count; i++)
                {
                    if (cookie.Split('=')[0] == oldcookielist[i].Split('=')[0])
                    {
                        oldcookielist[i] = cookie;
                        isFind = true;
                        break;
                    }
                }
                if (!isFind)
                    oldcookielist.Add(cookie);
            }
        }
    }
    oldcookie = string.Empty;
    for (int i = 0; i < oldcookielist.Count; i++)
        oldcookie += oldcookielist[i] + ";";
    return oldcookie;
}