OPEN SOURCE PROJECT

invoke GetDlgItem, [hDlg], ID_EDIT
mov ebx, eax
invoke SendMessage, eax, WM_CLEAR, 0, 0
invoke OpenClipboard, NULL
invoke GetClipboardData, CF_TEXT
invoke SendMessage, ebx, WM_SETTEXT, 0, eax

Тоже самое только с SetClipboardData можно впихнуть что угодно изменяя только тип формата:

Clipboard Format
CF_BITMAP
CF_DIB
CF_DIB
CF_ENHMETAFILE
CF_METAFILEPICT
CF_OEMTEXT
CF_OEMTEXT
CF_TEXT
CF_TEXT
CF_UNICODETEXT
CF_UNICODETEXT

Conversion Format
CF_DIB
CF_BITMAP
CF_PALETTE
CF_METAFILEPICT
CF_ENHMETAFILE
CF_TEXT
CF_UNICODETEXT
CF_OEMTEXT
CF_UNICODETEXT
CF_OEMTEXT
CF_TEXT

UINT uFormat, // clipboard format
HANDLE hMem // data handle
);

Parameters

uFormat

Specifies a clipboard format. This parameter can be a registered format or any of the standard clipboard formats listed in the following Remarks section. For information about registered clipboard formats, see the RegisterClipboardFormat function.

hMem

Identifies the data in the specified format. This parameter can be NULL, indicating that the window provides data in the specified clipboard format (renders the format) upon request. If a window delays rendering, it must process the WM_RENDERFORMAT and WM_RENDERALLFORMATS messages.

Once SetClipboardData is called, the system owns the object identified by the hMem parameter. The application can read the data, but must not free the handle or leave it locked. If the hMem parameter identifies a memory object, the object must have been allocated using the GlobalAlloc function with the GMEM_MOVEABLE and GMEM_DDESHARE flags.