Getting users who belong to the given role
[C#]
using CMS.SiteProvider; 
 // Get role of specified name from current site RoleInfo role = CMS.SiteProvider.RoleInfoProvider.GetRoleInfo("ArticleEditor", CMS.CMSHelper.CMSContext.CurrentSiteName); 
 if (role != null) { // Get datatable of the role members System.Data.DataTable users = CMS.SiteProvider.RoleInfoProvider.GetRoleUsers(role.RoleID); 
 if (users != null) { // the table now contains the users that belong to the given role ... } }  | 
Get user's roles
[C#]
using CMS.SiteProvider; 
 // Get UserInfo of the specified name UserInfo user = CMS.SiteProvider.UserInfoProvider.GetUserInfo("Alice"); 
 if (user != null) { // Get table with all user roles System.Data.DataTable table = CMS.SiteProvider.UserInfoProvider.GetUserRoles(user); 
 if (table != null) { // the table now contains the roles the user is member of... } }  | 
Adding user to role
[C#]
// Use UserName, RoleName and SiteName to add user to role CMS.SiteProvider.UserInfoProvider.AddUserToRole("Alice", "DocumentEditor", CMS.CMSHelper.CMSContext.CurrentSiteName);  | 
Removing user from role
[C#]
// Use UserName, RoleName and SiteName to remove user from role CMS.SiteProvider.UserInfoProvider.RemoveUserFromRole("Alice", "DocumentEditor", CMS.CMSHelper.CMSContext.CurrentSiteName);  | 
Checking if user is member of a given role
See Checking user permissions for more details.
Page url: http://devnet.kentico.com/docs/5_5r2/devguide/index.html?managing_user_roles.htm