RoleProvider.RoleExists Method

Gets a value indicating whether the specified role name already exists in the role data source for the configured applicationName.

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

'Declaration
Public MustOverride Function RoleExists ( _
	roleName As String _
) As Boolean
'Usage
Dim instance As RoleProvider
Dim roleName As String
Dim returnValue As Boolean

returnValue = instance.RoleExists(roleName)
public abstract boolean RoleExists (
	String roleName
)
public abstract function RoleExists (
	roleName : String
) : boolean
Not applicable.

Parameters

roleName

The name of the role to search for in the data source.

Return Value

true if the role name already exists in the data source for the configured applicationName; otherwise, false.

RoleExists is called by the RoleExists method of the Roles class to determine whether a role name exists in the data source for the configured ApplicationName.

If the specified roleName is a null reference (Nothing in Visual Basic) or is an empty string, we recommend that your provider throw an exception.

The following code example shows a sample implementation of the RoleExists method.

Public Overrides Function RoleExists(ByVal rolename As String) As Boolean

    If rolename Is Nothing OrElse rolename = "" Then _
      Throw New ProviderException("Role name cannot be empty or null.")

    Dim exists As Boolean = False

    Dim conn As OdbcConnection = New OdbcConnection(connectionString)
    Dim cmd As OdbcCommand = New OdbcCommand("SELECT COUNT(*) FROM Roles " & _
                                             " WHERE Rolename = ? AND ApplicationName = ?", conn)

    cmd.Parameters.Add("@Rolename", OdbcType.VarChar, 255).Value = rolename
    cmd.Parameters.Add("@ApplicationName", OdbcType.VarChar, 255).Value = ApplicationName

    Try
        conn.Open()

        Dim numRecs As Integer = CType(cmd.ExecuteScalar(), Integer)

        If numRecs > 0 Then
            exists = True
        End If
    Catch e As OdbcException
        ' Handle exception.
    Finally
        conn.Close()
    End Try

    Return exists
End Function

Windows 98, Windows Server 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

Community Additions

ADD
Show: