C# 无需预览即可打印WebBrowser,即单击打印
我有一个c#.Net应用程序,它可以打开一个自定义打印预览表单(与显示HTML文件的WebBrowser表单控件和一个打印web浏览器控件内容的按钮不同):C# 无需预览即可打印WebBrowser,即单击打印,c#,.net,printing,webbrowser-control,C#,.net,Printing,Webbrowser Control,我有一个c#.Net应用程序,它可以打开一个自定义打印预览表单(与显示HTML文件的WebBrowser表单控件和一个打印web浏览器控件内容的按钮不同): webBrowser.Print(); 但是,我现在想打印HTML文件而不打开此表单 我尝试将html加载到webbrowser表单中,但不显示表单,并调用了webbrowser.Print()但是没有任何东西可以打印。似乎只有当我显示表单并将HTML加载到控件中时,我才能打印。我知道的唯一方法是将网站呈现为图像,然后以静默方式打印。也许
webBrowser.Print();
但是,我现在想打印HTML文件而不打开此表单
我尝试将html加载到webbrowser表单中,但不显示表单,并调用了webbrowser.Print()但是没有任何东西可以打印。似乎只有当我显示表单并将HTML加载到控件中时,我才能打印。我知道的唯一方法是将网站呈现为图像,然后以静默方式打印。也许project会帮到你。你正在尝试的是调用 无声印刷
也许你应该根据你的技术来搜索替代方案。表单和WPF的实现方式各不相同。我有一个示例控制台应用程序,它使用WinForms
WebBrowser
打印一组HTML文件。你可以借用它的DoWorkAsync
部分,在WinForms应用程序中执行打印任务,几乎不需要任何更改:
// by Noseratio - http://stackoverflow.com/users/1768303/noseratio
using System;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace ConsoleApplicationWebBrowser
{
class Program
{
// Entry Point of the console app
static void Main(string[] args)
{
try
{
// download each page and dump the content
var task = MessageLoopWorker.Run(DoWorkAsync,
"http://www.example.com", "http://www.example.net", "http://www.example.org");
task.Wait();
Console.WriteLine("DoWorkAsync completed.");
}
catch (Exception ex)
{
Console.WriteLine("DoWorkAsync failed: " + ex.Message);
}
Console.WriteLine("Press Enter to exit.");
Console.ReadLine();
}
// navigate WebBrowser to the list of urls in a loop
static async Task<object> DoWorkAsync(object[] args)
{
Console.WriteLine("Start working.");
var wb = new WebBrowser();
wb.ScriptErrorsSuppressed = true;
if (wb.Document == null && wb.ActiveXInstance == null)
throw new ApplicationException("Unable to initialize the underlying WebBrowserActiveX");
// get the underlying WebBrowser ActiveX object;
// this code depends on SHDocVw.dll COM interop assembly,
// generate SHDocVw.dll: "tlbimp.exe ieframe.dll",
// and add as a reference to the project
var wbax = (SHDocVw.WebBrowser)wb.ActiveXInstance;
TaskCompletionSource<bool> loadedTcs = null;
WebBrowserDocumentCompletedEventHandler documentCompletedHandler = (s, e) =>
loadedTcs.TrySetResult(true); // turn event into awaitable task
TaskCompletionSource<bool> printedTcs = null;
SHDocVw.DWebBrowserEvents2_PrintTemplateTeardownEventHandler printTemplateTeardownHandler = (p) =>
printedTcs.TrySetResult(true); // turn event into awaitable task
// navigate to each URL in the list
foreach (var url in args)
{
loadedTcs = new TaskCompletionSource<bool>();
wb.DocumentCompleted += documentCompletedHandler;
try
{
wb.Navigate(url.ToString());
// await for DocumentCompleted
await loadedTcs.Task;
}
finally
{
wb.DocumentCompleted -= documentCompletedHandler;
}
// the DOM is ready,
Console.WriteLine(url.ToString());
Console.WriteLine(wb.Document.Body.OuterHtml);
// print the document
printedTcs = new TaskCompletionSource<bool>();
wbax.PrintTemplateTeardown += printTemplateTeardownHandler;
try
{
wb.Print();
// await for PrintTemplateTeardown - the end of printing
await printedTcs.Task;
}
finally
{
wbax.PrintTemplateTeardown -= printTemplateTeardownHandler;
}
Console.WriteLine(url.ToString() + " printed.");
}
wb.Dispose();
Console.WriteLine("End working.");
return null;
}
}
// a helper class to start the message loop and execute an asynchronous task
public static class MessageLoopWorker
{
public static async Task<object> Run(Func<object[], Task<object>> worker, params object[] args)
{
var tcs = new TaskCompletionSource<object>();
var thread = new Thread(() =>
{
EventHandler idleHandler = null;
idleHandler = async (s, e) =>
{
// handle Application.Idle just once
Application.Idle -= idleHandler;
// return to the message loop
await Task.Yield();
// and continue asynchronously
// propogate the result or exception
try
{
var result = await worker(args);
tcs.SetResult(result);
}
catch (Exception ex)
{
tcs.SetException(ex);
}
// signal to exit the message loop
// Application.Run will exit at this point
Application.ExitThread();
};
// handle Application.Idle just once
// to make sure we're inside the message loop
// and SynchronizationContext has been correctly installed
Application.Idle += idleHandler;
Application.Run();
});
// set STA model for the new thread
thread.SetApartmentState(ApartmentState.STA);
// start the thread and await for the task
thread.Start();
try
{
return await tcs.Task;
}
finally
{
thread.Join();
}
}
}
}
//按比例-http://stackoverflow.com/users/1768303/noseratio
使用制度;
使用系统线程;
使用System.Threading.Tasks;
使用System.Windows.Forms;
命名空间控制台应用程序WebBrowser
{
班级计划
{
//控制台应用程序的入口点
静态void Main(字符串[]参数)
{
尝试
{
//下载每个页面并转储内容
var task=MessageLoopWorker.Run(DoWorkAsync,
"http://www.example.com", "http://www.example.net", "http://www.example.org");
task.Wait();
WriteLine(“DoWorkAsync已完成”);
}
捕获(例外情况除外)
{
Console.WriteLine(“DoWorkAsync失败:+ex.Message”);
}
控制台。WriteLine(“按Enter键退出”);
Console.ReadLine();
}
//将WebBrowser导航到循环中的URL列表
静态异步任务DoWorkAsync(对象[]args)
{
Console.WriteLine(“开始工作”);
var wb=新的WebBrowser();
wb.ScriptErrorsSuppressed=true;
if(wb.Document==null&&wb.ActiveXInstance==null)
抛出新的ApplicationException(“无法初始化底层WebBrowserActiveX”);
//获取底层WebBrowser ActiveX对象;
//此代码依赖于SHDocVw.dll COM互操作程序集,
//生成SHDocVw.dll:“tlbimp.exe ieframe.dll”,
//并添加为项目的参考
var wbax=(SHDocVw.WebBrowser)wb.ActiveXInstance;
TaskCompletionSource loadedTcs=null;
WebBrowserDocumentCompletedEventHandler documentCompletedHandler=(s,e)=>
loadedTcs.TrySetResult(true);//将事件转换为可等待的任务
TaskCompletionSource printedTcs=null;
SHDocVw.DWebBrowserEvents2_PrintTemplateTeardownEventHandler printTemplateTeardownHandler=(p)=>
printedTcs.TrySetResult(true);//将事件转换为可等待的任务
//导航到列表中的每个URL
foreach(参数中的变量url)
{
loadedTcs=new TaskCompletionSource();
wb.DocumentCompleted+=documentCompletedHandler;
尝试
{
导航(url.ToString());
//等待文档完成
等待加载的任务;
}
最后
{
wb.DocumentCompleted-=documentCompletedHandler;
}
//DOM已经准备好了,
Console.WriteLine(url.ToString());
Console.WriteLine(wb.Document.Body.OuterHtml);
//打印文档
printedTcs=新任务完成源();
wbax.PrintTemplateTeardown+=printTemplateTeardownHandler;
尝试
{
wb.Print();
//等待打印模板拆卸-打印结束
等待打印的任务;
}
最后
{
wbax.PrintTemplateTeardown-=printTemplateTeardownHandler;
}
Console.WriteLine(url.ToString()+“printed.”);
}
wb.Dispose();
控制台写入线(“结束工作”);
返回null;
}
}
//用于启动消息循环并执行异步任务的帮助器类
公共静态类MessageLoopWorker
{
公共静态异步任务运行(Func worker,params object[]args)
{
var tcs=new TaskCompletionSource();
变量线程=新线程(()=>
{
EventHandler idleHandler=null;
idleHandler=async(s,e)=>
{
//处理应用程序。仅空闲一次
Application.Idle-=idleHandler;
//返回到消息循环
等待任务;
//并异步继续
//提出结果或例外
尝试
{
var结果=等待工作人员(args);
tcs.SetResult(结果);
}
捕获(例外情况除外)
{
tcs.SetException(ex);
}
//退出消息循环的信号
//此时将退出Application.Run
Application.ExitThread();
};
//处理应用程序。仅空闲一次
//确保我们在消息循环中