Pasting Information from the Clipboard

In the Label application, the application-defined EditPaste function pastes the content of the clipboard. This function does the following:

1. Opens the clipboard by calling the OpenClipboard function.
2. Determines which of the available clipboard formats to retrieve.
3. Retrieves the handle of the data in the selected format by calling the GetClipboardData function.
4. Inserts a copy of the data into the document.

   The handle returned by GetClipboardData is still owned by the clipboard, so an application must not free it or leave it locked.

5. Closes the clipboard by calling the CloseClipboard function.

If a label is selected and contains an insertion point, the EditPaste function inserts the text from the clipboard at the insertion point. If there is no selection or if a label is selected, the function creates a new label, using the application-defined LABELBOX structure on the clipboard. The LABELBOX structure is placed on the clipboard by using a registered clipboard format.

Following is the EditPaste function.

VOID WINAPI EditPaste(VOID) 
{ 
    PLABELBOX pbox; 
    HGLOBAL   hglb; 
    LPTSTR    lptstr; 
    PLABELBOX pboxCopy; 
    int cx, cy; 
    HWND hwnd; 
 
    pbox = hwndSelected == NULL ? NULL : 
        (PLABELBOX) GetWindowLong(hwndSelected, 0); 
 
    // If the application is in edit mode, 
    // get the clipboard text. 
 
    if (pbox != NULL && pbox->fEdit) 
    { 
        if (!IsClipboardFormatAvailable(CF_TEXT)) 
            return; 
        if (!OpenClipboard(hwndMain)) 
            return; 
 
        hglb = GetClipboardData(CF_TEXT); 
        if (hglb != NULL) 
        { 
            lptstr = GlobalLock(hglb); 
            if (lptstr != NULL) 
            { 
                // Call the application-defined ReplaceSelection 
                // function to insert the text and repaint the 
                // window. 
 
                ReplaceSelection(hwndSelected, pbox, lptstr); 
                GlobalUnlock(hglb); 
            } 
        } 
        CloseClipboard(); 
 
        return; 
    } 
 
    // If the application is not in edit mode, 
    // create a label window. 
 
    if (!IsClipboardFormatAvailable(uLabelFormat)) 
        return; 
    if (!OpenClipboard(hwndMain)) 
        return; 
 
    hglb = GetClipboardData(uLabelFormat); 
    if (hglb != NULL) 
    { 
        pboxCopy = GlobalLock(hglb); 
        if (pboxCopy != NULL) 
        { 
            cx = pboxCopy->rcText.right + CX_MARGIN; 
            cy = pboxCopy->rcText.top * 2 + cyText; 
 
            hwnd = CreateWindowEx( 
                WS_EX_NOPARENTNOTIFY | WS_EX_TRANSPARENT, 
                atchClassChild, NULL, WS_CHILD, 0, 0, cx, cy, 
                hwndMain, NULL, hinst, NULL 
            ); 
            if (hwnd != NULL) 
            { 
                pbox = (PLABELBOX) GetWindowLong(hwnd, 0); 
                memcpy(pbox, pboxCopy, sizeof(LABELBOX)); 
                ShowWindow(hwnd, SW_SHOWNORMAL); 
                SetFocus(hwnd); 
            } 
            GlobalUnlock(hglb); 
        } 
    } 
    CloseClipboard(); 
}