How to find groups & get users from SharePoint People Picker programmatically ?

string[] strEmployee = splstCurItem["peoplepicker"].ToString().Split(';','#');                               

List<string> lstUID = new List<string>();

List<string> lstUserID = new List<string>();

for (int i = 2; i < strEmployee.Length; i += 4)

{

lstUID.Clear();

Contact c = Contact.FromName(strEmployee[i-2], myWeb);

if (c != null)

{

string strUserType = c.PrincipalType.ToString();

if (strUserType == "SecurityGroup")

{

lstUID = GetUsersFromADGroup(strEmployee[i-2]);

lstUserID.AddRange(lstUID);

}

else if (strUserType == "SharePointGroup")

{

lstUID = GetUsersFromSharePointGroup(strEmployee[i-2]);

lstUserID.AddRange(lstUID);

}

else if (strUserType == "User")

{

lstUID.Add(strEmployee[i]);

lstUserID.AddRange(lstUID);

}

}

}

//Method1

List<int> GetUsersFromADGroup(string GroupName)

        {

            List<int> lstUsrID = new List<int>();

            SPSite MySite = new SPSite(workflowProperties.WebUrl);

            SPWeb Myweb = MySite.OpenWeb();

            Contact c = Contact.FromName(GroupName, Myweb);

            if (c != null)

            {

                Contact[] contacts = new Contact[] { c };

                bool reachedMaxCount = false;

                contacts = Contact.ExpandGroups(Myweb, contacts, 100, out reachedMaxCount);

                foreach (Contact user in contacts)

                {

                    string strID = user.PrincipalID.ToString();

                    string strName = user.DisplayName;

                    SPUser spUser = Myweb.EnsureUser(strName);

                    lstUsrID.Add(spUser.ID);

                }

            }

            return lstUsrID;

        }

 //Method2

  List<int> GetUsersFromSharePointGroup(string GroupName)

        {

            List<int> lstUsrID = new List<int>();

            SPSite MySite = new SPSite(workflowProperties.WebUrl);

            SPWeb Myweb = MySite.OpenWeb();

            SPGroup spGroup = Myweb.Groups[GroupName];

            foreach (SPUser spUser in spGroup.Users)

            {

                lstUsrID.Add(spUser.ID);

            }

            return lstUsrID;

        }