class procedure IfNotInRange(
    const AValue: Integer; 
    const AMin: Integer; 
    const AMax: Integer; 
    const AMsg: string = ''
);

IfNotInRange is a class procedure used to raise an instance of the exception class when the value in AValue is not in the range specified by AMin and AMax. When the value in AValue is not in the specified range, IfNotInRange calls Toss with the value in AMsg to raise the exception class instance. 

As a class method, IfNotInRange can be called without creating a prior instance of the exception class.

Using class methods in an Indy Exception descendant.

  EIdException.IfNotAssigned(AnObject, 'Object has not been created.');

  EIdException.IfAssigned(AnObject.Data, 'Object already has data.');

  EIdException.IfTrue(AnObject.ClosedGracefully,
    'Object connection has closed before completion.');

  EIdException.IfFalse(AnObject.Active,
    'Object connection is not open.');

  EIdException.IfNotInRange(AnObject.Port, 30000, 39999,
    'Object port number is invalid for this protocol.');

  // no exception raised... continue processing.