Roles.RoleExists Method
.NET Framework 3.0
Gets a value indicating whether the specified role name already exists in the role data source.
Namespace: System.Web.Security
Assembly: System.Web (in system.web.dll)
Roles Members
System.Web.Security Namespace
Assembly: System.Web (in system.web.dll)
The RoleExists method calls the RoleExists method of the default role provider to determine whether a role name exists in the data source for the application that is specified in the ApplicationName property.
The following code example uses the RoleExists method to determine whether a role name already exists before creating the role. For an example of a Web.config file that enables role management, see Roles.
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This example contains a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview (Visual Studio). |
<%@ Page Language="C#" %> <%@ Import Namespace="System.Web.Security" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script runat="server"> string[] rolesArray; public void Page_Load(object sender, EventArgs args) { if (!IsPostBack) { // Bind roles to GridView. rolesArray = Roles.GetAllRoles(); RolesGrid.DataSource = rolesArray; RolesGrid.DataBind(); } } public void CreateRole_OnClick(object sender, EventArgs args) { string createRole = RoleTextBox.Text; try { if (Roles.RoleExists(createRole)) { Msg.Text = "Role '" + Server.HtmlEncode(createRole) + "' already exists. Please specify a different role name."; return; } Roles.CreateRole(createRole); Msg.Text = "Role '" + Server.HtmlEncode(createRole) + "' created."; // Re-bind roles to GridView. rolesArray = Roles.GetAllRoles(); RolesGrid.DataSource = rolesArray; RolesGrid.DataBind(); } catch (Exception e) { Msg.Text = "Role '" + Server.HtmlEncode(createRole) + "' <u>not</u> created."; Response.Write(e.ToString()); } } </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head> <title>Sample: Create Role</title> </head> <body> <form runat="server" id="PageForm"> <h3>Create a Role</h3> <asp:Label id="Msg" ForeColor="maroon" runat="server" /><br /> Role name: <asp:TextBox id="RoleTextBox" runat="server" /> <asp:Button Text="Create Role" id="CreateRoleButton" runat="server" OnClick="CreateRole_OnClick" /> <br /> <asp:GridView runat="server" CellPadding="2" id="RolesGrid" Gridlines="Both" CellSpacing="2" AutoGenerateColumns="false" > <HeaderStyle BackColor="navy" ForeColor="white" /> <Columns> <asp:TemplateField HeaderText="Roles" > <ItemTemplate> <%# Container.DataItem.ToString() %> </ItemTemplate> </asp:TemplateField> </Columns> </asp:GridView> </form> </body> </html>
Reference
Roles ClassRoles Members
System.Web.Security Namespace
Other Resources
Understanding Role ManagementCommunity Additions
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