Delphi检查字符是否在A..Z和0..9范围内

function GetValueTrat(const aValue: string): string;

const

  CHARS = ['0'..'9', 'a'..'z', 'A'..'Z'];

var

  i: Integer;

begin

  Result := aValue.Trim;

  for i := 1 to Length(Result) do

  begin

    if not (Result[i] in CHARS) then

      raise Exception.Create('Non valido');

  end;

end;