Mega Code Archive
How to hook into the Clipboard Notification Chain
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Title: How to hook into the Clipboard Notification Chain
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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