IP编辑控件（因为封装的是系统自带控件，所以也使用了CreateSubClass，不过为啥要封装CN_COMMAND和CN_NOTIFY不是很明白）

最近需要用一个IP输入控件，网上找了几个，都不符合效果，有些还有一些奇怪的Bug。后来发现原来系统已经提供了IP地址编辑控件，只是系统提供的控件不能设置只读效果。网上找了下资料，封装了一下，自己迂回一下实现了只读效果。

源码下载

unit ueIPEdit;

interface

uses
  System.SysUtils, System.Classes, Vcl.Controls, Winapi.Windows, Winapi.Messages,
  Vcl.ComCtrls, Winapi.CommCtrl;

type
  TFieldChangeEvent = procedure(Sender: TObject; OldField, OldValue: Byte) of object;

  TUeIPEdit = class(TWinControl)
  private
    FState: Integer; //Internal use
    FBakIP: Longint; //Internal use
    FMinIP: Longint;
    FMaxIP: Longint;
    FOnChange: TNotifyEvent;
    FOnFieldChange: TFieldChangeEvent;
    procedure CNNotify(var Message: TWMNotify); message CN_NOTIFY;
    procedure CNCommand(var Message: TWMCommand); message CN_COMMAND;
  protected
    procedure CreateParams(var Params: TCreateParams); override;
    function  GetMinIP: String;
    function  GetMaxIP: String;
    procedure SetMinIP(const Value: String);
    procedure SetMaxIP(const Value: String);
    procedure UpdateRange;
    function  GetIP: String;
    procedure SetIP(const Value: String);
    function  GetEmpty: Boolean;
    function GetReadOnly: Boolean;
    procedure SetReadOnly(Value: Boolean);
    function IPToString(const AIp: Longint): String;
    function StringToIP(const Value: String): Longint;
  public
    constructor Create(AOwner: TComponent); override;
    procedure Clear;
    procedure SetActiveField(const Value: Integer);
    property Empty: Boolean read GetEmpty;
    property ReadOnly: Boolean read GetReadOnly write SetReadOnly;
    property IP: String read GetIP write SetIP;
    property MinIP: String read GetMinIP write SetMinIP;
    property MaxIP: String read GetMaxIP write SetMaxIP;
    property OnChange: TNotifyEvent read FOnChange write FOnChange;
    property OnIPFieldChange: TFieldChangeEvent read FOnFieldChange write FOnFieldChange;

    property Font;
    property ParentColor;
    property ParentFont;
    property ParentShowHint;
    property PopupMenu;
    property ShowHint;
    property TabOrder;
    property TabStop;
    property Tag;
    property DragCursor;
    property DragMode;
    property HelpContext;
  end;

implementation

uses Vcl.Graphics;

constructor TUeIPEdit.Create(AOwner: TComponent);
const
  EditStyle = [csClickEvents, csSetCaption, csDoubleClicks, csFixedHeight, csPannable];
begin
  inherited Create(AOwner);
  if NewStyleControls then
    ControlStyle := EditStyle else
    ControlStyle := EditStyle + [csFramed];
  ParentColor := False;
  Color := clWindow;
  Width:= 130;
  Height:= 20;
  TabStop:= True;
  FState := 0;
  FBakIP := -1;
  FMinIP:= 0;
  FMaxIP:= $0FFFFFFFF;
  FOnChange:= nil;
  FOnFieldChange:= nil;
end;

procedure TUeIPEdit.CreateParams(var Params: TCreateParams);
begin
  InitCommonControl(ICC_INTERNET_CLASSES);
  inherited CreateParams(Params);
  CreateSubClass(Params, WC_IPADDRESS);
  with Params do
  begin
    Style := WS_VISIBLE or WS_BORDER or WS_CHILD;
    if NewStyleControls and Ctl3D then
    begin
      Style := Style and not WS_BORDER;
      ExStyle := ExStyle or WS_EX_CLIENTEDGE;
    end;
  end;
end;

procedure TUeIPEdit.CNNotify(var Message: TWMNotify);
begin
  if (FState=0) and Assigned(FOnFieldChange) and
    (Message.NMHdr^.code=IPN_FIELDCHANGED) then
    FOnFieldChange(Self, PNMIPAddress(Message.NMHdr)^.iField,
        PNMIPAddress(Message.NMHdr)^.iValue);
end;

procedure TUeIPEdit.CNCommand(var Message: TWMCommand);
begin
  if (Message.NotifyCode = EN_CHANGE) then
  begin
    case FState of
      0: if Assigned(FOnChange) then FOnChange(Self);
      1: begin
           FState := 2;
           PostMessage(Handle, IPM_SETADDRESS, 0, FBakIP);
         end;
      2: FState := 1;
    end;
  end;
end;

function TUeIPEdit.IPToString(const AIp: Longint): String;
begin
  Result:= Format('%d.%d.%d.%d',[FIRST_IPADDRESS(AIp),SECOND_IPADDRESS(AIp),
    THIRD_IPADDRESS(AIp),FOURTH_IPADDRESS(AIp)]);
end;

function TUeIPEdit.StringToIp(const Value: String): Longint;
var
  B: array[0..3] of Byte;
  Strs: TArray<string>;
  i, Cnt : Integer;
begin
  B[0]:= 0;
  B[1]:= 0;
  B[2]:= 0;
  B[3]:= 0;
  if Value<>'' then
  begin
    Strs := Value.Split(['.'],TStringSplitOptions.ExcludeEmpty);
    try
      Cnt := Length(Strs);
      if Cnt>4 then Cnt := 4;
      for i := 0 to Cnt-1 do
        B[i] := StrToInt(Strs[i]);
    finally
      Strs := nil;
    end;
  end;
  Result:= MakeIPAddress(b[0], b[1], b[2], b[3]);
end;

function TUeIPEdit.GetIP: String;
var
  AIp: Longint;
begin
  SendMessage(Handle, IPM_GETADDRESS, 0, Longint(@AIp));
  Result:= IPToString(AIp);
end;

procedure TUeIPEdit.SetIP(const Value: String);
begin
  SendMessage(Handle, IPM_SETADDRESS, 0, StringToIp(Value));
end;

function TUeIPEdit.GetMinIP: String;
begin
  Result:= IPToString(FMinIP);
end;

procedure TUeIPEdit.SetMinIP(const Value: String);
var
  AMin: LongInt;
begin
  AMin := StringToIp(Value);
  if FMinIP<>AMin then
  begin
    FMinIP := AMin;
    UpdateRange;
  end;
end;

procedure TUeIPEdit.UpdateRange;
begin
  SendMessage(Handle, IPM_SETRANGE, 0, MAKEIPRANGE(FIRST_IPADDRESS(FMinIP), FIRST_IPADDRESS(FMaxIP)));
  SendMessage(Handle, IPM_SETRANGE, 1, MAKEIPRANGE(SECOND_IPADDRESS(FMinIP), SECOND_IPADDRESS(FMaxIP)));
  SendMessage(Handle, IPM_SETRANGE, 2, MAKEIPRANGE(THIRD_IPADDRESS(FMinIP), THIRD_IPADDRESS(FMaxIP)));
  SendMessage(Handle, IPM_SETRANGE, 3, MAKEIPRANGE(FOURTH_IPADDRESS(FMinIP), FOURTH_IPADDRESS(FMaxIP)));
end;

procedure TUeIPEdit.SetMaxIP(const Value: String);
var
  AMax: LongInt;
begin
  AMax := StringToIp(Value);
  if FMaxIP<>AMax then
  begin
    FMaxIP := AMax;
    UpdateRange;
  end;
end;

function TUeIPEdit.GetMaxIP: String;
begin
  Result:= IPToString(FMaxIP);
end;

function TUeIPEdit.GetReadOnly: Boolean;
begin
  Result := FState<>0;
end;

procedure TUeIPEdit.SetReadOnly(Value: Boolean);
begin
  if Value <> GetReadOnly then
  begin
    if Value then
    begin
      SendMessage(Handle, IPM_GETADDRESS, 0, Longint(@FBakIP));
      FState := 1;
    end else begin
      FState := 0;
    end;
  end;
end;

function TUeIPEdit.GetEmpty: Boolean;
begin
  Result:= Boolean(SendMessage(Handle, IPM_ISBLANK, 0, 0));
end;

procedure TUeIPEdit.Clear;
begin
  SendMessage(Handle, IPM_CLEARADDRESS, 0, 0);
end;

procedure TUeIPEdit.SetActiveField(const Value: Integer);
begin
  if (Value < 4) then
  begin
    SendMessage(Handle, IPM_SETFOCUS, wParam(Value), 0);
  end;
end;

end.