VC + + MFC Clipboard Operations Tutorial

This article mainly introduces the following clipboard operations in VC++/MFC:

1, the text content of the operation

2. Operation of WMF data

3, the bitmap operation

4. Set Use custom format

5, the perception of clipboard content changes

6. Automatically paste data into another application window

I. Operation of text content

The following code demonstrates how to copy text content to the Clipboard (Unicode encoding is first converted to ASCII):

CString source;

The text content is saved in the source variable

if (OpenClipboard ())

{

Hglobal Clipbuffer;

char * buffer;

EmptyClipboard ();

Clipbuffer = GlobalAlloc (gmem_ddeshare, source. GetLength () +1);

Buffer = (char*) globallock (Clipbuffer);

strcpy (buffer, LPCSTR (source));

GlobalUnlock (Clipbuffer);

SetClipboardData (Cf_text,clipbuffer);

CloseClipboard ();

}

The following code shows how to get textual content from the Clipboard:

char * buffer = NULL;

Open clipboard

CString Fromclipboard;

if (OpenClipboard ())

{

HANDLE hdata = GetClipboardData (cf_text);

char * buffer = (char*) globallock (hdata);

Fromclipboard = buffer;

GlobalUnlock (Hdata);

CloseClipboard ();

}

Ii. operation of WMF data

Reading and writing image data on the Clipboard is a useful feature, and it is simple to implement. The following code shows how to copy an extended metafile to the clipboard:

if (OpenClipboard ());

{

EmptyClipboard ();

To create a metafile DC

CMETAFILEDC * CDC = new CMetaFileDC ();

Cdc->createenhanced (GetDC (), Null,null, "the_name");

Calling a drawing routine

Close the CMetaFileDC and get its handle

Henhmetafile handle = cdc->closeenhanced ();

Copy to Clipboard

SetClipboardData (Cf_enhmetafile,handle);

CloseClipboard ();

Remove DC

Delete CDC;

}

The following code demonstrates obtaining a metafile from the Clipboard and drawing it onto a client DC:

if (OpenClipboard ())

{

Get Clipboard data

Henmetafile handle = (henmetafile) getclipboarddata (cf_enhmetafile);

Show

CCLIENTDC DC (this);

CRect client (0,0,200,200);

dc. PlayMetaFile (handle,client);

Close clipboard

CloseClipboard ();

}

Third, the operation of the bitmap

Bitmap operations are slightly more complex, and the following example shows how to save a bitmap on the Clipboard:

if (OpenClipboard ())

{

EmptyClipboard ();

CBitmap * junk = new CBitmap ();

CClientDC CDC (this);

CDC DC;

dc. CreateCompatibleDC (&CDC);

CRect client (0,0,200,200);

Junk->createcompatiblebitmap (&cdc,client. Width (), client. Height ());

dc. Selectobje

CT (junk);

DrawImage (&dc,cstring ("Bitmap"));

Copy Data to Clipboard

SetClipboardData (Cf_bitmap,junk->m_hobject);

CloseClipboard ();

Delete junk;

}

The following code shows how to obtain bitmap data from the Clipboard:

if (OpenClipboard ())

{

Get Clipboard data

Hbitmap handle = (HBITMAP) getclipboarddata (CF_BITMAP);

CBitmap * BM = cbitmap::fromhandle (handle);

CClientDC CDC (this);

CDC DC;

dc. CreateCompatibleDC (&CDC);

dc. SelectObject (BM);

Cdc. BitBlt (0,0,200,200,&dc,0,0,srccopy);

CloseClipboard ();

}

Iv. setting up and using custom formats

Using the RegisterClipboardFormat () function, you can copy and paste any data type you want. For example, we have one of the following data types:

struct Myformatdata

{

Long Val1;

int val2;

};

We're going to copy it to the Clipboard and we can use the following code:

UINT format = RegisterClipboardFormat ("My_custom_format");

if (OpenClipboard ())

{

Myformatdata data;

Data.val1 = 100;

Data.val2 = 200;

Hglobal Clipbuffer;

EmptyClipboard ();

Clipbuffer = GlobalAlloc (gmem_ddeshare, sizeof (Myformatdata));

Myformatdata * buffer = (myformatdata*) globallock (Clipbuffer);

>

Save to Memory

*buffer = data;

Save to Clipboard

GlobalUnlock (Clipbuffer);

SetClipboardData (Format,clipbuffer);

CloseClipboard ();

}

Read the data using the following code:

UINT format = RegisterClipboardFormat ("My_custom_format");

Myformatdata data;

if (OpenClipboard ())

{

HANDLE hdata =getclipboarddata (format);

Myformatdata * buffer = (myformatdata*) globallock (hdata);

data = *buffer;

GlobalUnlock (Hdata);

CloseClipboard ();

}

V. Perception of changes in clipboard content

The contents of the Clipboard can be sensed by Windows messages as follows:

In your initialization code call:

SetClipboardViewer (); Add our programs to the Clipboard Watch chain

In your message map add:

On_message (Wm_drawclipboard, Onclipchange)//Add message handle

Which is declared as:

afx_msg void Onclipchange ();

Finally Implement:

void Cdetectclipboardchangedlg::onclipchange ()

{

CTime time = Ctime::getcurrenttime ();

Setdlgitemtext (Idc_changed_date,time. Format ("%a,%b%d,%Y--%h:%m:%s"));

Displayclipboardtext ();

}

Automatically pasting data into another application window

Just get the handle to the appropriate window and send a message to it