WebView2 - Selecting text and copying to clipboard - visual-c++

Question

With the CHtmlView class I was able to select all the text and copy to the clipboard like this:
void CChristianLifeMinistryHtmlView::CopyToClipboard()
{
ExecWB(OLECMDID_COPY, OLECMDEXECOPT_DONTPROMPTUSER, nullptr, nullptr);
}
void CChristianLifeMinistryHtmlView::SelectAll()
{
ExecWB(OLECMDID_SELECTALL, OLECMDEXECOPT_DONTPROMPTUSER, nullptr, nullptr);
}
I am trying to find out how to do the same with the new WebView2 API.
Update
The WebView2 control supports by design:
CTRL + A to select all the content.
CTRL + C to copy the selected text to the clipboard.
I found a VB.NET solution to programatically copy all the page to the clipboard:
Sub Async GetText()
v = Await wv.ExecuteScriptAsync("document.body.innerText")
End Sub
But I am using Visual C++ and I do not see this method exposed. Also, I am not sure it is what I want because I do not want to copy as plain text data but HTML data (suitable for pasting in Word) like with the hotkeys. I have made a GitHub issue for this too.
Update
So I have now tried this code but it does not appear to do anything:
void CWebBrowser::CopyToClipboard()
{
if (m_pImpl->m_webView != nullptr)
{
m_pImpl->m_webView->ExecuteScript(_T("document.body.innerText"), nullptr);
}
}
Update
According to this article it states:
Alternately, for ICoreWebView2::ExecuteScript, you provide an instance that has an Invoke method that provides you with the success or failure code of the ExecuteScript request. Also provide the second parameter that is the JSON of the result of running the script.
Trying to find example.
Update
I now understand that I need to do something like this:
void CWebBrowser::CopyToClipboard()
{
if (m_pImpl->m_webView != nullptr)
{
m_pImpl->m_webView->ExecuteScript(L"document.body.innerText",
Callback<ICoreWebView2ExecuteScriptCompletedHandler>(
[](HRESULT error, PCWSTR result) -> HRESULT
{
if (error != S_OK) {
ShowFailure(error, L"ExecuteScript failed");
}
SetClipboardText(result);
AfxMessageBox(L"HTML copied to clipboard!", MB_OK);
return S_OK;
}).Get());
}
}
The variable result has the contents of the HTML page. But it does not like my call to SetClipboardText now. This is the error:
This is the function:
void CWebBrowser::SetClipboardText(CString strText)
{
BYTE* pbyText;
TCHAR* pcBuffer;
HANDLE hText;
UINT uLength;
//USES_CONVERSION ;
if (::OpenClipboard(nullptr))
{
// Empty it of all data first.
::EmptyClipboard();
// Replace previous text contents.
uLength = strText.GetLength();
//pcBuffer = T2A( (LPTSTR)(LPCTSTR)strText);
pcBuffer = strText.GetBuffer(uLength);
if (pcBuffer != nullptr)
{
hText = ::GlobalAlloc(GMEM_MOVEABLE | GMEM_DDESHARE, (uLength + 1) * sizeof(TCHAR));
if (hText != nullptr)
{
pbyText = (BYTE*)::GlobalLock(hText);
if (pbyText != nullptr)
{
// Deliberately not _tcscpy().
//strcpy_s( (char *)pbyText, uLength+1, pcBuffer);
_tcscpy_s((TCHAR*)pbyText, uLength + 1, pcBuffer);
::GlobalUnlock(hText);
::SetClipboardData(CF_UNICODETEXT, hText);
// Don't free this memory, clipboard owns it now.
}
}
}
::CloseClipboard();
strText.ReleaseBuffer(uLength);
}
}
This is the only way I know (to date) to copy to clipboard. So I have two issues here:
It will not let me use this function.
I expect it will copy just text (CF_UNICODETEXT) and I don't know if that is sufficient for pasting the data as HTML into Word?
Concerning issue 1, I needed to make the method static. Then it compiled and copied the information to the clipboard.
Concerning issue 2, as expected, the pasted data was stripped HTML and I was left with just the text. And the new line characters were displayed as "\n" in the text. It was one huge paragraph. So I do indeed need the CF_HTML format.
It is a pity that the WebView2 does not expose the copy to clipboard feature that it already has functional.
Update
This is the clipboard method that I found on the internet for CF_HTML:
// CopyHtml() - Copies given HTML to the clipboard.
// The HTML/BODY blanket is provided, so you only need to
// call it like CopyHtml("<b>This is a test</b>");
void CopyHTML(char* html)
{
// Create temporary buffer for HTML header...
char* buf = new char[400 + strlen(html)];
if (!buf) return;
// Get clipboard id for HTML format...
static int cfid = 0;
if (!cfid) cfid = RegisterClipboardFormat("HTML Format");
// Create a template string for the HTML header...
strcpy(buf,
"Version:0.9\r\n"
"StartHTML:00000000\r\n"
"EndHTML:00000000\r\n"
"StartFragment:00000000\r\n"
"EndFragment:00000000\r\n"
"<html><body>\r\n"
"<!--StartFragment -->\r\n");
// Append the HTML...
strcat(buf, html);
strcat(buf, "\r\n");
// Finish up the HTML format...
strcat(buf,
"<!--EndFragment-->\r\n"
"</body>\r\n"
"</html>");
// Now go back, calculate all the lengths, and write out the
// necessary header information. Note, wsprintf() truncates the
// string when you overwrite it so you follow up with code to replace
// the 0 appended at the end with a '\r'...
char* ptr = strstr(buf, "StartHTML");
wsprintf(ptr + 10, "%08u", strstr(buf, "<html>") - buf);
*(ptr + 10 + 8) = '\r';
ptr = strstr(buf, "EndHTML");
wsprintf(ptr + 8, "%08u", strlen(buf));
*(ptr + 8 + 8) = '\r';
ptr = strstr(buf, "StartFragment");
wsprintf(ptr + 14, "%08u", strstr(buf, "<!--StartFrag") - buf);
*(ptr + 14 + 8) = '\r';
ptr = strstr(buf, "EndFragment");
wsprintf(ptr + 12, "%08u", strstr(buf, "<!--EndFrag") - buf);
*(ptr + 12 + 8) = '\r';
// Now you have everything in place ready to put on the clipboard.
// Open the clipboard...
if (OpenClipboard(0))
{
// Empty what's in there...
EmptyClipboard();
// Allocate global memory for transfer...
HGLOBAL hText = GlobalAlloc(GMEM_MOVEABLE | GMEM_DDESHARE, strlen(buf) + 4);
// Put your string in the global memory...
char* ptr = (char*)GlobalLock(hText);
strcpy(ptr, buf);
GlobalUnlock(hText);
::SetClipboardData(cfid, hText);
CloseClipboard();
// Free memory...
GlobalFree(hText);
}
// Clean up...
delete[] buf;
}
But it is not compatible with the PCWSTR variable.
Update
I have now realised after doing debugging that ExecuteScript does return the actual HTML data if I use document.body.innerText. The resulting string is just text with \n characters for the new lines. It is not in HTML format. So I am back to square one.

Answer 1

Just use ICoreWebView2::ExecuteScript.

Answer 2

I am showing this as an alternative because the current approach does not include the actual HTML content. The information I found on the internet was misleading about using document.body.innerText.
One solution to this is to use the document.execCommand() route. I added the following methods to my browser class:
void CWebBrowser::SelectAll()
{
if (m_pImpl->m_webView != nullptr)
{
m_pImpl->m_webView->ExecuteScript(L"document.execCommand(\"SelectAll\")", nullptr);
}
}
void CWebBrowser::CopyToClipboard2()
{
if (m_pImpl->m_webView != nullptr)
{
m_pImpl->m_webView->ExecuteScript(L"document.execCommand(\"Copy\")", nullptr);
}
}
Then I added the following button handlers to my dialog to test:
void CMFCTestWebView2Dlg::OnBnClickedButtonSelectAll()
{
if (m_pWebBrowser != nullptr)
{
m_pWebBrowser->SelectAll();
}
}
void CMFCTestWebView2Dlg::OnBnClickedButtonCopyToClipboard()
{
if (m_pWebBrowser != nullptr)
{
m_pWebBrowser->CopyToClipboard2();
}
}
This does work and appears to be the simplest solution for now. I see references to the Calendar API as an alternative but I am not sure yet how to implement that approach.
My only concern with execCommand is that I have seen it documented as deprecated.