cefsharp winform silent print to pdf if js callback window.print()
Question
I've a problem with a popup and print it to pdf silently. When I push print button (on the site), it's open a popup, generate a barcode and then popup prints. The popup contain two js functions window.print() and then window.close() . I need to print this popup silently to pdf, but I don't found nothing about this method. Currently I intercept through ILifeSpanHandler, but targetUrl contain a static link and not contain barcode generated. I think the popup must be print as is bypassing window.print() and block print dialog. Can someone help me? Thank you so much.
EDITED
This is the js popup that I need to print silently to pdf. It is parent popup:
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title></title>
<script src="xxxx"></script>
<script src="xxxx/js/jquery-1.11.1.min.js" type="text/javascript"></script>
<script src="xxxx/js/lib/barcode/JsBarcode.all.min.js?v=20200729001"></script>
<script src="xxxx/js/lib/qrcode/qrcode.min.js?v=20200729001"></script>
<style>
#logo, #barcodes, #qrcode{
text-align:center;
}
img{
display:initial!important;
}
</style>
</head>
<script type="text/javascript">
$(document).ready(function() {
var qrcode = window.qrcode;
var parentData = window.data;
console.log(parentData);
console.log("Start");
var c = parentData;
var id = 'id-'+c;
if(qrcode){
$("#barcodes").append("<div id='"+id+"' style=\"text-align:center;\"/><br/>");
new QRCode(document.getElementById(id), {
text: c,
width: 128,
height: 128,
colorDark : "#000000",
colorLight : "#ffffff",
correctLevel : QRCode.CorrectLevel.H
});
$('#'+id).append('<br/> <br/> <div id="qrcode" style="font-weight:bold;">' + c + '</div>');
}else{
$("#barcodes").append("<img id='"+id+"' /><br/>");
JsBarcode("#" + id, c, {format: "CODE128", height:60});
}
console.log(parentData);
console.log("End");
console.log(parentData);
});
</script>
<body>
<div id="logo">
<img style=" height: auto; width: auto; max-width: 300px; max-height: 300px;" src="xxxx">
<br>
<img style="height: auto; width: auto; max-width: 253px; max-height: 253px;" src="xxxx">
</div>
<br />
<div id="barcodes"></div>
</body>
</html>
window.data (coupon) is passed through key cookie value. I think that ILifeSpanHandler must intecpet and print to pdf file and close it self.
EDITED
I've tried:
using System;
using System.IO;
using CefSharp;
namespace CefSharp
{
public class EnablePrint : ILifeSpanHandler
{
bool ILifeSpanHandler.DoClose(IWebBrowser chromiumWebBrowser, IBrowser browser)
{
var coupon = browser.PrintToPdfAsync("c://coupon//text.pdf", new PdfPrintSettings
{
MarginType = CefPdfPrintMarginType.Custom,
MarginBottom = 0,
MarginTop = 0,
MarginLeft = 0,
MarginRight = 0,
ScaleFactor = 95
});
coupon.ContinueWith(exit =>
browser.GetHost().CloseBrowser(true));
return true;
}
void ILifeSpanHandler.OnAfterCreated(IWebBrowser chromiumWebBrowser, IBrowser browser)
{
}
void ILifeSpanHandler.OnBeforeClose(IWebBrowser chromiumWebBrowser, IBrowser browser)
{
}
bool ILifeSpanHandler.OnBeforePopup(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, string targetUrl, string targetFrameName, WindowOpenDisposition targetDisposition, bool userGesture, IPopupFeatures popupFeatures, IWindowInfo windowInfo, IBrowserSettings browserSettings, ref bool noJavascriptAccess, out IWebBrowser newBrowser)
{
newBrowser = null;
return false;
}
}
}
This code generate an exception:
System.ObjectDisposedException
HResult=0x80131622
Messaggio=Impossibile accedere a un oggetto eliminato.
Nome oggetto: 'This instance of CefSharp.IBrowser been disposed!'.
Origine=CefSharp.Core
Analisi dello stack:
in CefSharp.Internals.CefWrapper.ThrowIfDisposed()
in CefSharp.Internals.CefSharpBrowserWrapper.GetHost()
in PremierClient_x86.EnablePrint.<>c__DisplayClass0_0.<CefSharp.ILifeSpanHandler.DoClose>b__0(Task`1 exit) in C:\Users\XXXXXXX\EnablePrint.cs: riga 23
in System.Threading.Tasks.ContinuationTaskFromResultTask`1.InnerInvoke()
in System.Threading.Tasks.Task.Execute()
The popup ramian on front and I cannot manually close.
1 answers
solution1
0 2020-08-26 03:43:23
Based on the example give above you'll have to close the popup window manually, which is easy enough. The code will look something like below (it compiles though I haven't tested as I don't have a working example to go from).
using System;
using System.Runtime.InteropServices;
using CefSharp;
namespace CefSharp.MinimalExample.WinForms
{
public class LifeSpanHandler : ILifeSpanHandler
{
[DllImport("user32.dll")]
private static extern bool DestroyWindow(IntPtr hWnd);
[DllImport("user32.dll")]
private static extern IntPtr GetTopWindow(IntPtr hWnd);
bool ILifeSpanHandler.DoClose(IWebBrowser chromiumWebBrowser, IBrowser browser)
{
//Only do this for popups
if(!browser.IsPopup)
{
return false;
}
var hwnd = browser.GetHost().GetWindowHandle();
browser.PrintToPdfAsync("c://coupon//text.pdf", new PdfPrintSettings()).ContinueWith(exit =>
{
//You may need to get the top level window and close that instead
//var parentHwnd = GetTopWindow(hwnd);
//DestroyWindow(parentHwnd);
//Close the browser, if the popup window doesn't close then
//get the top level window and close that instead (code commented out above)
DestroyWindow(hwnd);
});
//Cancel close, destroy window manually after pdf generated
return true;
}
void ILifeSpanHandler.OnAfterCreated(IWebBrowser chromiumWebBrowser, IBrowser browser)
{
}
void ILifeSpanHandler.OnBeforeClose(IWebBrowser chromiumWebBrowser, IBrowser browser)
{
}
bool ILifeSpanHandler.OnBeforePopup(IWebBrowser chromiumWebBrowser, IBrowser browser, IFrame frame, string targetUrl, string targetFrameName, WindowOpenDisposition targetDisposition, bool userGesture, IPopupFeatures popupFeatures, IWindowInfo windowInfo, IBrowserSettings browserSettings, ref bool noJavascriptAccess, out IWebBrowser newBrowser)
{
newBrowser = null;
return false;
}
}
}
Additionally to avoid showing the print dialog you can inject some javascript to override window.print and make it a noop
namespace CefSharp.MinimalExample.WinForms
{
internal class LoadHandler : ILoadHandler
{
void ILoadHandler.OnFrameLoadEnd(IWebBrowser chromiumWebBrowser, FrameLoadEndEventArgs args)
{
}
void ILoadHandler.OnFrameLoadStart(IWebBrowser chromiumWebBrowser, FrameLoadStartEventArgs args)
{
if (args.Browser.IsPopup)
{
//Override window.print so it does nothing
args.Browser.MainFrame.ExecuteJavaScriptAsync("window.print = function () { };");
}
}
void ILoadHandler.OnLoadError(IWebBrowser chromiumWebBrowser, LoadErrorEventArgs args)
{
}
void ILoadHandler.OnLoadingStateChange(IWebBrowser chromiumWebBrowser, LoadingStateChangedEventArgs args)
{
}
}
}
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