Assign Group permission to list item using client object model

Question

Hi,
   I am trying to add the list item and assign the permission to the list item by using SP 2010 client object model. The problem which i am facing that when i assign the group as a permission to the item, by automatically the limited access permission
is added to the group. Please find the steps which i have followed,
Step-1: Break role inheritance.
 foreach (var item in _listItemCollection)
                        if (item["FileLeafRef"].ToString().ToLower() == "xxx")
                            item.BreakRoleInheritance(true, false);
                            _clientContext.Load(item.RoleAssignments);
                            _folderItem = item;
_clientContext.ExecuteQuery();
Step 2: Remove all permissions of the list item.
   foreach (var assignment in _folderItem.RoleAssignments)
                    assignment.RoleDefinitionBindings.RemoveAll();
                    assignment.Update();
_clientContext.ExecuteQuery();
Step 3:
    Add Group as a permission to the list item.
  var role = _web.RoleDefinitions.GetByType(RoleType.Contributor);
                var collRdb = new RoleDefinitionBindingCollection(_clientContext) { role };
                Principal principal = _grp;
                _folderItem.RoleAssignments.Add(principal, collRdb);
                _folderItem.Update();
_clientContext.ExecuteQuery();
    After adding the group successfully to the list item, i checked the group permission and it contains the value as "Contribute,Limited Access" to the site level and "Contribute" to the list item. Please guide me how to avoid to create Contribute,Limited
Access role.
Balaji

Answer 1

Hi Dmitry,
  When I create the group and assign contribute permission, the group has the permission at the site level(to see the permission, click group and click view Group Permission).  I have added the list item and break the role inheritance permission
and given the unique permission by providing group as a permission to the list item. After providing the permission, the group permission at the site level changed to "Contribute, Limited Access". I dont know how contribute permission changed to contribute,
limited access.
I found the workaround to fix this issue. I created the group and create the folder in the shared document library by using client object model. Due to facing some issue by providing the permission using client object model, i have created the event receiver
to the document library and using server object model, i can able to assign the approprate group permission.
Balaji