Public MustOverride Function RoleExists ( _
    roleName As String _
) As Boolean

Dim instance As RoleProvider
Dim roleName As String
Dim returnValue As Boolean

returnValue = instance.RoleExists(roleName)

public abstract bool RoleExists (
    string roleName
)

public:
virtual bool RoleExists (
    String^ roleName
) abstract

public abstract boolean RoleExists (
    String roleName
)

public abstract function RoleExists (
    roleName : String
) : boolean

Public Overrides Function RoleExists(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 [" & rolesTable & "]" & _
                                           " 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

public override bool RoleExists(string rolename)
{
  if (rolename == null || rolename == "")
    throw new ProviderException("Role name cannot be empty or null.");

  bool exists = false;

  OdbcConnection conn = new OdbcConnection(connectionString);
  OdbcCommand cmd = new OdbcCommand("SELECT COUNT(*) FROM [" + rolesTable + "]"  +
                                    " 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();

    int numRecs = (int)cmd.ExecuteScalar();

    if (numRecs > 0)
    {
      exists = true;
    }
  }
  catch (OdbcException)
  {
    // Handle exception.
  }
  finally
  {
    conn.Close();      
  }

  return exists;
}