Cannot change permissions of root web : On Using web.BreakRoleInheritance(true, false);

Question

I am new to SharePoint programming and had written the below code to access all groups and group users from a site collection including all subsites using web.BreakRoleInheritance(true, false); .

So that I can access the subites that has broken inheritance and holding unique permission . But I am facing the error

Cannot change permissions of root web

Can any one let me know what's wrong in my below code

DataTable datatable = new DataTable();
            DataColumn datacolumn1 = new DataColumn("Site_URL");
            DataColumn datacolumn2 = new DataColumn("Login_Email");
            DataColumn datacolumn3 = new DataColumn("Login_User");
            DataColumn datacolumn4 = new DataColumn("Site_Group");

            datatable.Columns.Add(datacolumn1);
            datatable.Columns.Add(datacolumn2);
            datatable.Columns.Add(datacolumn3);
            datatable.Columns.Add(datacolumn4);

            try
            {
                SPSecurity.RunWithElevatedPrivileges(delegate()
                {
                    using (SPSite site = new SPSite(SPContext.Current.Site.ID))
                    {
                        foreach (SPWeb web in site.AllWebs)
                        {
                            foreach (SPGroup group in web.Groups)
                            {
                                web.BreakRoleInheritance(true, false);
                                DataRow newrow = datatable.NewRow();


                                foreach (SPUser user in web.SiteUsers)
                                {
                                    newrow["Login_User"] = user.LoginName;
                                    newrow["Site_Group"] = group.Name;
                                    newrow["Login_Email"] = user.Email;
                                    newrow["Site_URL"] = web.Url;
                                    datatable.Rows.Add(newrow);
                                }

                            }
                            GridView1.DataSource = datatable;
                            GridView1.DataBind();
                        }
                    }
                });
            }
            catch(Exception ee)
            {

                Label1.Text = ee.Message;

            }

Answer 1

First, Based on your code, you don't need to use web.BreakRoleInheritance(true, false);

Second, Adding web.BreakRoleInheritance(true, false); in the foreach of SPGroup is pointless!!!

Third, the above code will not achieve your goal (access the subsites that have broken inheritance and holding unique permission) it just loops for each site user and adds it to grid view and logically it's wrong because you are trying to loop for each group then get the same site users!!

• Check

  • Stop inheriting permissions programatically
  • BreakRoleInheritance on SPWeb object?

Fourth, yes you can't break the inheritance of the root site because it's the parent site!!