Seeking FOSS IPv4 address picker VCL component - delphi

Question

Strictly for use in the reserved address ranges, so IPv4 is good enough. I don't know yet if I will use class A, B or C (probably C, but ...) so it would be a bonus to be able to handle all.
And extra bonus if I can also enter something like "localhost", although I can live without that.
So, minimum requirement is to specify a 192.xxx.xxx.xxx and make sure that xxx does not exceed 255.
Sure, I could knock one up with a few mask edits, but surely someone has invented that particular (FOSS) wheel before?
Note to self: if you do have to code it, this page looks useful

Answer 1

Windows has a built-in IP Address edit control. You can wrap that in a custom TWinControl descendant component for easy access and reuse, eg:
type
TIPAddressFieldChange = procedure(Sender: TObject; Field: Integer; Value: Integer) of object;
TIPAddress = class(TWinControl)
private
FOnFieldChange: TIPAddressFieldChange;
function GetIP: String;
function GetIsEmpty: Boolean;
procedure SetIP(const Value: String);
protected
procedure CreateParams(var Params: TCreateParams); override;
procedure CNNotify(var Message: TWMNotify); message CN_NOTIFY;
procedure WMGetDlgCode(var Message: TMessage); message WM_GETDLGCODE;
procedure WMSetFont(var Message: TWMSetFont); message WM_SETFONT;
public
constructor Create(Owner: TComponent); override;
procedure Clear;
property IP: String read GetIP write SetIP;
property IsEmpty: Boolean read GetIsEmpty;
published:
property OnFieldChange: TIPAddressFieldChange read FOnFieldChange write FOnFieldChange;
end;
.
uses
Commctrl;
constructor TIPAddress.Create(Owner: TComponent);
begin
inherited;
InitCommonControl(ICC_INTERNET_CLASSES};
end;
procedure TIPAddress.CreateParams(var Params: TCreateParams);
begin
inherited;
CreateSubClass(Params, WC_IPADDRESS);
Params.Style := WS_CHILD or WS_TABSTOP or WS_VISIBLE;
if NewStyleControls and Ctl3D then
begin
Params.Style := Params.Style and not WS_BORDER;
Params.ExStyle := Params.ExStyle or WS_EX_CLIENTEDGE;
end;
Params.WindowClass.style := Params.WindowClass.style and not (CS_HREDRAW or CS_VREDRAW);
end;
procedure TIPAddress.Clear;
begin
Perform(IPM_CLEARADDRESS, 0, 0);
end;
function TIPAddress.GetIP: String;
var
dwIp: DWORD;
begin
dwIp := 0;
Perform(IPM_GETADDRESS, 0, LPARAM(#dwIp));
Result := Format('%d.%d.%d.%d', [FIRST_IPADDRESS(dwIp), SECOND_IPADDRESS(dwIp),
THIRD_IPADDRESS(dwIp), FOURTH_IPADDRESS(dwIp)]);
end;
function TIPAddress.GetIsEmpty: Boolean;
begin
Result := Perform(IPM_ISBLANK, 0, 0) <> 0;
end;
procedure TIPAddress.SetIP(const Value: String);
var
dwIP: LPARAM;
begin
with TStringList.Create do try
Delimiter := '.';
StrictDelimiter := True;
DelimitedText := Value;
Assert(Count = 4);
dwIP := MAKEIPADDRESS(StrToInt(Strings[0]), StrToInt(Strings[1]), StrToInt(Strings[2]), StrToInt(Strings[3]));
finally
Free;
end;
Perform(IPM_SETADDRESS, 0, dwIP);
end;
procedure TIPAddress.CNNotify(var Message: TWMNotify);
begin
inherited;
if (Message.NMHdr^.code = IPN_FIELDCHANGED) and Assigned(FOnFieldChange) then
begin
with PNMIPAddress(Message.NMHdr)^ do
FOnFieldChange(Self, iField, iValue);
end;
end;
procedure TIPAddress.WMGetDlgCode(var Message: TMessage);
begin
inherited;
Message.Result := Message.Result or DLGC_WANTARROWS;
end;
procedure TIPAddress.WMSetFont(var Message: TWMSetFont);
var
LF: LOGFONT;
begin
if GetObject(Message.Font, SizeOf(LF), #LF) <> 0 then
begin
Message.Font := CreateFontIndirect(LF);
inherited;
end;
end;

Answer 2

What about to try the TJvIPAddress from the JEDI Visual Component Library ? It has the automatic range value correction and it derives from the standard Windows IP edit box.