如何解决如果js回调window.print,则将cefsharp winform静默打印为pdf
我在弹出窗口时遇到问题,并以静默方式将其打印为pdf。
当我按下“打印”按钮(在站点上)时,它会打开一个弹出窗口,生成条形码,然后弹出打印。
弹出窗口包含两个js函数window.print()
,然后是window.close()
。
我需要将此弹出窗口以静默方式打印为pdf,但是我对此方法一无所获。
目前,我通过ILifeSpanHandler进行拦截,但targetUrl包含静态链接,不包含生成的条形码。我认为弹出窗口必须像绕过window.print()
一样打印并阻止打印对话框。
有人能帮我吗?
非常感谢。
已编辑
这是我需要静默打印到pdf的js弹出窗口。这是父级弹出窗口:
<!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
(优惠券)通过关键Cookie值传递。
我认为ILifeSpanHandler
必须保护并打印到pdf文件并自行关闭。
已编辑
我尝试过:
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;
}
}
}
此代码生成异常:
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()
前面的弹出式拉面,我无法手动关闭。
解决方法
根据上面给出的示例,您必须手动关闭弹出窗口,这很容易。代码如下所示(尽管我没有经过测试的示例,但仍可以编译)。
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;
}
}
}
另外,为避免显示“打印”对话框,您可以注入一些JavaScript来覆盖window.print并将其设为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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