Read All users related to RoleDefinition of ProjectSite using CSOM - sharepoint

Question

I need to loop through all RoleDefinitiona of ProjectSite and get all users related to each one and add those users to a RoleDefinition of a ProjectSite in another SiteCollection
I can loop through RoleDefinitions like :
using (var src_ctx = new ClientContext(Root))
{
RoleDefinitionCollection role_definition_collection = src_ctx.Web.RoleDefinitions;
src_ctx.Load(role_definition_collection);
src_ctx.ExecuteQuery();
foreach (RoleDefinition role_definition in role_definition_collection)
{
}
}
also I can loop through all groups and read users of each group then get RoleAssignment of each user:
GroupCollection group_collection = src_ctx.Web.SiteGroups;
src_ctx.Load(group_collection);
src_ctx.ExecuteQuery();
foreach (Group group in group_collection)
{
UserCollection user_collection = group.Users;
foreach (User user in user_collection)
{
RoleAssignment role_assignment = src_ctx.Web.RoleAssignments.GetByPrincipal(user);
RoleDefinitionBindingCollection role_definition_binding_collection = role_assignment.RoleDefinitionBindings;
}
}
but how can I link between RoleDefinition and users ?

Answer 1

the following class used to copy users with its permissions, may help someone
public static class UserHelper
{
// static members
private static Dictionary<string, string> Levels = new Dictionary<string, string>();
private static void Prepare_Dictionary()
{
Levels["Full Control"] = "Full Control";
Levels["Design"] = "Design";
Levels["Contribute"] = "Contribute";
Levels["Read"] = "Read";
Levels["Limited Access"] = "Limited Access";
}
public static void Start_Moving_Users(string Root2010,string Root2013)
{
Prepare_Dictionary();
using (ClientContext src_ctx = new ClientContext(Root2010))
{
using (ClientContext dest_ctx = new ClientContext(Root2013))
{
dest_ctx.Web.BreakRoleInheritance(true, false);
RoleAssignmentCollection src_rac = src_ctx.Web.RoleAssignments;
src_ctx.Load(src_rac);
src_ctx.ExecuteQuery();
foreach (RoleAssignment src_ra in src_rac)
{
try
{
src_ctx.Load(src_ra.Member);
src_ctx.ExecuteQuery();
RoleDefinitionBindingCollection src_rdb = src_ra.RoleDefinitionBindings;
src_ctx.Load(src_rdb);
src_ctx.ExecuteQuery();
RoleDefinition src_rd = src_rdb[0];
src_ctx.Load(src_rd);
src_ctx.ExecuteQuery();
Principal dest_user = dest_ctx.Web.EnsureUser(src_ra.Member.LoginName);
RoleDefinition dest_rd = dest_ctx.Web.RoleDefinitions.GetByName(Levels[src_rd.Name]);
RoleDefinitionBindingCollection dest_rdb = new RoleDefinitionBindingCollection(dest_ctx);
dest_rdb.Add(dest_rd);
dest_ctx.Web.RoleAssignments.Add(dest_user, dest_rdb);
dest_ctx.ExecuteQuery();
}
catch { continue; }
}
}
}
}
}