The best way to do this is modified by personal self. Using user Id, I can get all information of user and then construct a user box just like in directory module. Below are some code demonstrate my work, hope they can be helped.

//Get current loged user id
public int GetUserId()
    {
        try
        {
            UserInfo _currentUser = DotNetNuke.Entities.Users.UserController.GetCurrentUserInfo();
            return _currentUser.UserID;
        }
        catch
        {
            return -1;
        }
    } 

//Get all user roles base on user name
public string[] GetUserRoles(string userName)
    {
        try
        {
            return Roles.GetRolesForUser(userName);
        }
        catch
        {
            return null;
        }
    }

//Detect current loged user's role
public string DetectDNNUser()
    {
        var userInfo = UserController.GetCurrentUserInfo();
        if (userInfo.IsInRole("Administrators"))
        {
            return "Administrators";
        }
        else if (userInfo.IsInRole("Admin Group"))
        {
            return "Admin Group";
        }
        return "";
    } 

//Get user info base on user id
public UserInfo GetUserInfo(int userId)
    {
        PortalSettings portalSettings = new PortalSettings();
        int portalId = portalSettings.PortalId;
        DotNetNuke.Entities.Users.UserController oUserController = new DotNetNuke.Entities.Users.UserController();
        UserInfo userInfo = oUserController.GetUser(portalId, userId);
        return userInfo;
    }

Besides there is an easy way to do this, that is link user name to the ActiveFeed page. All user information and control goes here.

Eg: <a href='http://" + GetDefaultPortalAlias() + "/ActivityFeed/tabid/" + 60 + "/userId/" + UserId + "'>username</a>

 //Get default Portal Allias
public string GetDefaultPortalAlias()
    {
        try
        {
            PortalSettings portalSettings = new PortalSettings();
            int portalId = portalSettings.PortalId;
            string defaultPortalAlias = portalSettings.DefaultPortalAlias;
            return defaultPortalAlias;
        }
        catch
        {
            return null;
        }
    }

//Get current tab name by tab id
public string GetCurrentTabName(int tabId)
    {
        DotNetNuke.Entities.Tabs.TabController tabController = new DotNetNuke.Entities.Tabs.TabController();
        DotNetNuke.Entities.Tabs.TabInfo tabInfo = tabController.GetTab(tabId);
        string tabName = tabInfo.TabName;
        return tabName;
    }

//Get current tab id by tabname
    public int GetCurrentTabId(string tabName)
    {
        int PageTabId = 0;
        DotNetNuke.Entities.Tabs.TabInfo objTab = default(DotNetNuke.Entities.Tabs.TabInfo);
        DotNetNuke.Entities.Tabs.TabController objTabs = default(DotNetNuke.Entities.Tabs.TabController);
        objTab = objTabs.GetTabByName(tabName, GetDefaultPortalId());
        PageTabId = objTab.TabID;
        return PageTabId;
    }

Best Regards,

Dung Tri