禁止改变ListView的列宽

prevent resizing of listview columns?

Author: jiyong jang  

unit TestUnit;

interface

uses

 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

 Dialogs, ComCtrls;

type

 TForm1 = class(TForm)

   ListView1: TListView;

   procedure FormShow(Sender: TObject);

   procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);

 private

   { Private declarations }

   WndMethod: TWndMethod;

   function GetIndex(aNMHdr: pNMHdr): Integer;

   procedure CheckMesg(var aMesg: TMessage);

 public

   { Public declarations }

 end;

var

 Form1: TForm1;

implementation

uses

 CommCtrl;

{$R *.dfm}

function TForm1.GetIndex(aNMHdr: pNMHdr): Integer;

var

 hHWND: HWND;

 HdItem: THdItem;

 iIndex: Integer;

 iResult: Integer;

 iLoop: Integer;

 sCaption: string;

 sText: string;

 Buf: array [0..128] of Char;

begin

 Result := -1;

 hHWND := aNMHdr^.hwndFrom;

 iIndex := pHDNotify(aNMHdr)^.Item;

 FillChar(HdItem, SizeOf(HdItem), 0);

 with HdItem do

 begin

   pszText    := Buf;

   cchTextMax := SizeOf(Buf) - 1;

   Mask       := HDI_TEXT;

 end;

 Header_GetItem(hHWND, iIndex, HdItem);

 with ListView1 do

 begin

   sCaption := Columns[iIndex].Caption;

   sText    := HdItem.pszText;

   iResult  := CompareStr(sCaption, sText);

   if iResult = 0 then

     Result := iIndex

   else

   begin

     iLoop := Columns.Count - 1;

     for iIndex := 0 to iLoop do

     begin

       iResult := CompareStr(sCaption, sText);

       if iResult <> 0 then

         Continue;

       Result := iIndex;

       break;

     end;

   end;

 end;

end;

procedure TForm1.CheckMesg(var aMesg: TMessage);

var

 HDNotify: ^THDNotify;

 NMHdr: pNMHdr;

 iCode: Integer;

 iIndex: Integer;

begin

 case aMesg.Msg of

   WM_NOTIFY:

     begin

       HDNotify := Pointer(aMesg.lParam);

       iCode := HDNotify.Hdr.code;

       if (iCode = HDN_BEGINTRACKW) or

         (iCode = HDN_BEGINTRACKA) then

       begin

         NMHdr := TWMNotify(aMesg).NMHdr;

         // chekck column index

         iIndex := GetIndex(NMHdr);

         // prevent resizing of columns if index's less than 3

         if iIndex < 3 then

           aMesg.Result := 1;

       end

       else

         WndMethod(aMesg);

     end;

   else

     WndMethod(aMesg);

 end;

end;

procedure TForm1.FormShow(Sender: TObject);

begin

 WndMethod := ListView1.WindowProc;

 ListView1.WindowProc := CheckMesg;

end;

procedure TForm1.FormCloseQuery(Sender: TObject; var CanClose: Boolean);

begin

 ListView1.WindowProc := WndMethod;

end;