Get all sitecollection users

http://social.msdn.microsoft.com/Forums/en-US/sharepointdevelopment/thread/20a6d15b-764a-4080-bfa6-7eca4d2f296e


public void Button1_Click(object sender, EventArgs e)
{
Hashtable myHashTable = new Hashtable();

using (SPSite site = new SPSite(TextBox1.Text))
{
using (SPWeb web = site.OpenWeb())
{
SPWebCollection sites1 = web.Webs;
if (sites1.Count == 0)
{
SPUserCollection usercol = web.SiteUsers;
foreach (SPUser oUser in usercol)
{

if (!myHashTable.Contains(oUser.ID))
{
myHashTable.Add(oUser.ID, oUser.Name);
}

}
//foreach (SPGroup group in web.SiteGroups)
//{
// foreach (SPUser singleUser in group.Users)
// {
// if (!myHashTable.Contains(singleUser.ID))
// {
// myHashTable.Add(singleUser.ID, singleUser.Name);
// }
// }
//}
dropDownSite.Items.Add("NO Sub Sites");

GridView1.DataSource = myHashTable;
GridView1.DataBind();
}
else
{
foreach (SPWeb subSite in sites1)
{
SPUserCollection usercol = subSite.AllUsers;
foreach (SPUser oUser in usercol)
{
if (!myHashTable.Contains(oUser.ID))
{
myHashTable.Add(oUser.ID, oUser.Name);
}

}

dropDownSite.Items.Add(subSite.Url);

GridView1.DataSource = myHashTable;
GridView1.DataBind();
}

}


}
}

}

group Owners update using code

http://social.msdn.microsoft.com/Forums/en/sharepointdevelopment/thread/8c253efe-096c-4537-affd-0a0fdb1a132b


http://social.msdn.microsoft.com/Forums/en/sharepointdevelopment/thread/1ea65718-8728-402c-8c8f-1532d757a2b3