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AuthorizationStoreRoleProvider.RoleExists Method

Gets a value indicating whether the specified role name already exists in the authorization-manager policy store.

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

public override bool RoleExists(
	string roleName
)

Parameters

roleName
Type: System.String

The name of the role to search for in the authorization-manager policy store.

Return Value

Type: System.Boolean
true if the role name already exists in the authorization-manager policy store; otherwise, false.

ExceptionCondition
ArgumentNullException

roleName is null.

ArgumentException

roleName is an empty string.

-or-

roleName contains a comma.

ProviderException

The configured applicationName was not found.

-or-

The configured scopeName was not found.

-or-

The authorization-manager runtime is not installed on the server.

FileNotFoundException

The connectionStringName attribute references a connection string to a file that does not exist.

HttpException

The AuthorizationStoreRoleProvider instance is configured with a file-based policy store, and read access to the file is not allowed at the current trust level.

The RoleExists method is called by the Roles class to determine whether a role name exists in the authorization-manager data store specified in the ASP.NET application's configuration file (Web.config).

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 AuthorizationStoreRoleProvider.

<%@ 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>

.NET Framework

Supported in: 4.6, 4, 3.5, 3.0, 2.0

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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