AddUsersToRoles Method

Roles.AddUsersToRoles Method (String[], String[])


Adds the specified users to the specified roles.

Namespace:   System.Web.Security
Assembly:  System.Web (in System.Web.dll)

public static void AddUsersToRoles(
	string[] usernames,
	string[] roleNames


Type: System.String[]

A string array of user names to add to the specified roles.

Type: System.String[]

A string array of role names to add the specified user names to.

Exception Condition

One of the roles in roleNames is null.


One of the users in usernames is null.


One of the roles in roleNames is an empty string or contains a comma (,).


One of the users in usernames is an empty string or contains a comma (,).


roleNames contains a duplicate element.


usernames contains a duplicate element.


Role management is not enabled.

The AddUsersToRoles method calls the default role provider to associate the specified users with the specified roles at the data source.

If your application uses the SqlRoleProvider class, the database updates that are performed during the call to the AddUsersToRoles method are made within a transaction. If an error is encountered, such as a user name that is already in a specified role, the transaction is rolled back and no updates are performed.


User names and role names cannot contain commas.

The following code example adds one or more users to one or more roles. For an example of a Web.config file that enables role management, see Roles.

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Web.Security" %>
<%@ Import Namespace="System.Web.UI" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
<script runat="server">

string[] rolesArray;
MembershipUserCollection users;

public void Page_Load()
  Msg.Text = "";

  if (!IsPostBack)
    // Bind roles to ListBox.

    rolesArray = Roles.GetAllRoles();
    RolesListBox.DataSource = rolesArray;

    // Bind users to ListBox.

    users = Membership.GetAllUsers();
    UsersListBox.DataSource = users;

public void AddUsers_OnClick(object sender, EventArgs args)
  // Verify that at least one user and one role are selected.

  int[] user_indices = UsersListBox.GetSelectedIndices();

  if (user_indices.Length == 0)
    Msg.Text = "Please select one or more users.";

  int[] role_indices = RolesListBox.GetSelectedIndices();

  if (role_indices.Length == 0)
    Msg.Text = "Please select one or more roles.";

  // Create list of users to be added to the selected roles.

  string[] newusers = new string[user_indices.Length];

  for (int i = 0; i < newusers.Length; i++)
    newusers[i] = UsersListBox.Items[user_indices[i]].Value;

  // Create list of roles to be add the selected users to.

  string[] rolesList = new string[role_indices.Length];

  for (int i = 0; i < rolesList.Length; i++)
    rolesList[i] = RolesListBox.Items[role_indices[i]].Value;

  // Add the users to the selected role.

    Roles.AddUsersToRoles(newusers, rolesList);  
    Msg.Text = "User(s) added to Role(s).";
  catch (HttpException e)
    Msg.Text = e.Message;

<html xmlns="" >
<title>Sample: Role Membership</title>

<form runat="server" id="PageForm">
  <h3>Role Membership</h3>
  <asp:Label id="Msg" ForeColor="maroon" runat="server" /><br />
  <table cellpadding="3" border="0">
      <td valign="top">Roles:</td>
      <td valign="top"><asp:ListBox id="RolesListBox" runat="server" SelectionMode="Multiple"
                                    Rows="8" /></td>
      <td valign="top">Users:</td>
      <td valign="top"><asp:ListBox id="UsersListBox" DataTextField="Username" 
                                  Rows="8" SelectionMode="Multiple" runat="server" /></td>
      <td valign="top"><asp:Button Text="Add User(s) to Role(s)" id="AddUsersButton"
                                 runat="server" OnClick="AddUsers_OnClick" /></td>


.NET Framework
Available since 2.0
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