Hook на буфер обмена

{ 
  *Just create a new form and call it ClipFormats. 
  *Drop a TButton and call it btnUpdate. 
  *Drop a TListBox and call it lbFormats. 
 
  Then just add the code below and hook up all the event handlers. 
  All it does is display all the formats currently on the clipboard and 
  updates as soon as the clipboard changes. 
}
 
 unit DynaClip;
 
 interface
 
 uses
   Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
   Dialogs, StdCtrls, ExtCtrls;
 
 type
   TClipFormats = class(TForm)
     btnUpdate: TButton;
     lbFormats: TListBox;
     procedure FormCreate(Sender: TObject);
     procedure FormDestroy(Sender: TObject);
     procedure btnUpdateClick(Sender: TObject);
   private
     { Private declarations }
     NextWindow: HWND;
     procedure WMChangeCBChain(var Message: TWMChangeCBChain); message
     WM_CHANGECBCHAIN;
     procedure WMDrawClipboard(var Message: TWMDrawClipboard); message
     WM_DRAWCLIPBOARD;
   public
     { Public declarations }
   end;
 
 var
   ClipFormats: TClipFormats;
 
 implementation
 
 {$R *.DFM}
 
 procedure TMDIChildClipFormats.FormCreate(Sender: TObject);
 begin
   NextWindow := SetClipboardViewer(Handle);
 end;
 
 procedure TClipFormats.FormDestroy(Sender: TObject);
 begin
   ChangeClipboardChain(Handle, NextWindow);
 end;
 
 procedure TClipFormats.WMChangeCBChain(var Message: TWMChangeCBChain);
 begin
   with Message do
    begin
     if (Remove = NextWindow) then
      begin
       NextWindow := Next;
     end
     else
      begin
       SendMessage(NextWindow, WM_CHANGECBCHAIN, Remove, Next);
     end;
   end;
 end;
 
 procedure TClipFormats.WMDrawClipboard(var Message: TWMDrawClipboard);
 begin
   btnUpdate.Click;
   SendMessage(NextWindow, WM_DRAWCLIPBOARD, 0, 0);
 end;
 
 procedure TClipFormats.btnUpdateClick(Sender: TObject);
 const
   PreDefinedFormats: array[1..16] of string = ('CF_TEXT',
     'CF_BITMAP',
     'CF_METAFILEPICT',
     'CF_SYLK',
     'CF_DIF',
     'CF_TIFF',
     'CF_OEMTEXT',
     'CF_DIB',
     'CF_PALETTE',
     'CF_PENDATA',
     'CF_RIFF',
     'CF_WAVE',
     'CF_UNICODETEXT',
     'CF_ENHMETAFILE',
     'CF_HDROP',
     'CF_LOCALE');
 var
   ClipFormat: TClipFormat;
   szBuffer: array[0..511] of Char;
   FormatID: string;
 begin
   if not OpenClipboard(Handle) then Exit;
   try
     lbFormats.Items.BeginUpdate;
     try
       lbFormats.Items.Clear;
 
       ClipFormat := EnumClipboardFormats(0);
       while (ClipFormat <> 0) do
        begin
         if (ClipFormat in [1..16]) then
          begin
           FormatID := PreDefinedFormats[ClipFormat];
         end
         else
          begin
           GetClipboardFormatName(ClipFormat, szBuffer, SizeOf(szBuffer));
           FormatID := string(szBuffer);
         end;
         lbFormats.Items.Add(Format('%s [%d]', [FormatID, ClipFormat]));
         ClipFormat := EnumClipboardFormats(ClipFormat);
       end;
     finally
       lbFormats.Items.EndUpdate;
     end;
   finally
     CloseClipboard;
   end;
 end;
 
 end.

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