unit Unit3;

interface

uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants,
System.Classes, Vcl.Graphics, Vcl.Controls, Vcl.Forms, Vcl.Dialogs,
Vcl.StdCtrls, Vcl.ExtCtrls;

type
TForm3 = class(TForm)
Button1: TButton;
Edit1: TEdit;
Image1: TImage;
ListBox1: TListBox;
procedure Button1Click(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure FormCreate(Sender: TObject);
procedure ListBox1Click(Sender: TObject);
private { Private declarations }
//处理WM_DRAWCLIPBOARD消息过程
procedure WMDrawClipBoard(var AMessage: TMessage); message WM_DRAWCLIPBOARD;
public { Public declarations }
end;

var
Form3: TForm3;
NextClipHwnd: HWND; //观察链中下一个窗口句柄

implementation

{$R *.dfm}

uses
jpeg, Clipbrd;

procedure TForm3.Button1Click(Sender: TObject);
begin
if CliPBoard.HasFormat(CF_TEXT) then
Edit1.Text := CliPBoard.AsText;

if CliPBoard.HasFormat(CF_BITMAP) then
ShowMessage('位图');
if CliPBoard.HasFormat(CF_METAFILEPICT) then
ShowMessage('元文件');
if CliPBoard.HasFormat(CF_PICTURE) then
ShowMessage('CF_PICTURE');
if CliPBoard.HasFormat(CF_COMPONENT) then
ShowMessage('CF_COMPONENT');
if CliPBoard.HasFormat(CF_OEMTEXT) then
ShowMessage('CF_OEMTEXT');
if CliPBoard.HasFormat(CF_UNICODETEXT) then
ShowMessage('CF_UNICODETEXT');

{
HANDLE GetClipboardData( UINT uFormat
);
uFormat
[in] Specifies a clipboard format. For a description of the standard clipboard formats, Value Meaning
CF_BITMAP A handle to a bitmap (HBITMAP).
CF_DIB A memory object containing a BITMAPINFO structure followed by the bitmap bits.
CF_DIBV5 Windows 2000/XP: A memory object containing a BITMAPV5HEADER structure followed by the bitmap color space information and the bitmap bits.
CF_DIF Software Arts' Data Interchange Format.
CF_DSPBITMAP Bitmap display format associated with a private format. The hMem parameter must be a handle to data that can be displayed in bitmap format in lieu of the privately formatted data.
CF_DSPENHMETAFILE Enhanced metafile display format associated with a private format. The hMem parameter must be a handle to data that can be displayed in enhanced metafile format in lieu of the privately formatted data.
CF_DSPMETAFILEPICT Metafile-picture display format associated with a private format. The hMem parameter must be a handle to data that can be displayed in metafile-picture format in lieu of the privately formatted data.
CF_DSPTEXT Text display format associated with a private format. The hMem parameter must be a handle to data that can be displayed in text format in lieu of the privately formatted data.
CF_ENHMETAFILE A handle to an enhanced metafile (HENHMETAFILE).
CF_GDIOBJFIRST through CF_GDIOBJLAST Range of integer values for application-defined Microsoft Windows Graphics Device Interface (GDI) object clipboard formats. Handles associated with clipboard formats in this range are not automatically deleted using the GlobalFree function when the clipboard is emptied. Also, when using values in this range, the hMem parameter is not a handle to a GDI object, but is a handle allocated by the GlobalAlloc function with the GMEM_MOVEABLE flag.
CF_HDROP A handle to type HDROP that identifies a list of files. An application can retrieve information about the files by passing the handle to the DragQueryFile functions.
CF_LOCALE The data is a handle to the locale identifier associated with text in the clipboard. When you close the clipboard, if it contains CF_TEXT data but no CF_LOCALE data, the system automatically sets the CF_LOCALE format to the current input language. You can use the CF_LOCALE format to associate a different locale with the clipboard text.
An application that pastes text from the clipboard can retrieve this format to determine which character set was used to generate the text.

Note that the clipboard does not support plain text in multiple character sets. To achieve this, use a formatted text data type such as Rich Text Format (RTF) instead.

Windows NT/2000/XP: The system uses the code page associated with CF_LOCALE to implicitly convert from CF_TEXT to CF_UNICODETEXT. Therefore, the correct code page table is used for the conversion.

CF_METAFILEPICT Handle to a metafile picture format as defined by the METAFILEPICT structure. When passing a CF_METAFILEPICT handle by means of Dynamic Data Exchange (DDE), the application responsible for deleting hMem should also free the metafile referred to by the CF_METAFILEPICT handle.
CF_OEMTEXT Text format containing characters in the OEM character set. Each line ends with a carriage return/linefeed (CR-LF) combination. A null character signals the end of the data.
CF_OWNERDISPLAY Owner-display format. The clipboard owner must display and update the clipboard viewer window, and receive the WM_ASKCBFORMATNAME, WM_HSCROLLCLIPBOARD, WM_PAINTCLIPBOARD, WM_SIZECLIPBOARD, and WM_VSCROLLCLIPBOARD messages. The hMem parameter must be NULL.
CF_PALETTE Handle to a color palette. Whenever an application places data in the clipboard that depends on or assumes a color palette, it should place the palette on the clipboard as well.
If the clipboard contains data in the CF_PALETTE (logical color palette) format, the application should use the SelectPalette and RealizePalette functions to realize (compare) any other data in the clipboard against that logical palette.
When displaying clipboard data, the clipboard always uses as its current palette any object on the clipboard that is in the CF_PALETTE format.

CF_PENDATA Data for the pen extensions to the Microsoft Windows for Pen Computing.
CF_PRIVATEFIRST through CF_PRIVATELAST Range of integer values for private clipboard formats. Handles associated with private clipboard formats are not freed automatically; the clipboard owner must free such handles, typically in response to the WM_DESTROYCLIPBOARD message.
CF_RIFF Represents audio data more complex than can be represented in a CF_WAVE standard wave format.
CF_SYLK Microsoft Symbolic Link (SYLK) format.
CF_TEXT Text format. Each line ends with a carriage return/linefeed (CR-LF) combination. A null character signals the end of the data. Use this format for ANSI text.
CF_WAVE Represents audio data in one of the standard wave formats, such as 11 kHz or 22 kHz Pulse Code Modulation (PCM).
CF_TIFF Tagged-image file format.
CF_UNICODETEXT Windows NT/2000/XP: Unicode text format. Each line ends with a carriage return/linefeed (CR-LF) combination. A null character signals the end of the data.
}
end;

procedure TForm3.FormClose(Sender: TObject; var Action: TCloseAction);
begin
//从观察链中删除本观察窗口
ChangeClipboardChain(Handle, NextClipHwnd);
//将WM_DRAWCLIPBOARD消息传递到下一个观察链中的窗口
SendMessage(NextClipHwnd, WM_CHANGECBCHAIN, Handle, NextClipHwnd);
end;

procedure TForm3.FormCreate(Sender: TObject);
begin
//获得观察链中下一个窗口句柄
NextClipHwnd := SetClipBoardViewer(Handle);
end;

procedure TForm3.ListBox1Click(Sender: TObject);
begin
if ListBox1.Items.Count >= 0 then
if ListBox1.Items.Strings[ListBox1.ItemIndex] = 'Bitmap' then
begin
Clipboard.Open;
Clipboard.Clear;
Clipboard.SetAsHandle(CF_BITMAP, Image1.Picture.Bitmap.Handle);
Clipboard.Close;
end
else
begin
Clipboard.Open;
ClipBoard.Clear;
Clipboard.AsText := ListBox1.Items.Strings[ListBox1.ItemIndex];
ClipBoard.Close;
end;
end;

procedure TForm3.WMDrawClipBoard(var AMessage: TMessage);
begin
//将WM_DRAWCLIPBOARD消息传递到下一个观察链中的窗口
if NextClipHwnd <> 0 then
SendMessage(NextClipHwnd, AMessage.Msg, AMessage.WParam, AMessage.LParam);
//处理剪贴板中内容
if Clipboard.HasFormat(CF_TEXT) or Clipboard.HasFormat(CF_OEMTEXT) then
begin
//查询剪贴板中特定格式的数据内容
ListBox1.Items.Add(Clipboard.asText + '...');
end;
if Clipboard.HasFormat(CF_BITMAP) then
begin
ListBox1.Items.Add('Bitmap');
Image1.Picture.Bitmap.LoadFromClipboardFormat(CF_BITMAP, clipboard.GetAsHandle(CF_BITMAP), 0);
end;
end;

end.