【发布时间】：2010-10-19 05:27:49
【问题描述】：
我正在为一家小型企业开发 Intranet ASP.NET MVC2 应用程序。小型企业有多种类型的打印机，根据需要，打印请求将（从浏览器/用户）发送到服务器，服务器将相应地将打印作业发送到正确的打印机。请注意，这对他们来说是一个全新的环境，我几乎可以控制一切。我很可能会使用非常轻量级的操作系统（可能是 Asus ExpressGate 或 Chrome 操作系统，具体取决于发布日期？），因此用户无法安装任何打印机，但服务器将完成所有设置。
这是我的问题：
有没有一种简单的方法可以通过使用 html 链接作为参数并保持 HTML 格式从服务器端打印页面（当然没有对话框，因为不会有人等待点击它们）当然。
我已经看到了 COM 的一些可能性，但如果有可能通过使用 .net 类来避免这种情况，我将不胜感激。我正在使用.net 4.0。但是，即使它是基于 COM 的，我也会接受任何建议。
编辑：请注意，任何有意义的解决方法也将被考虑在内，一个快速（尚未研究）的示例是将此 html 传输到 doc 文件并将此文件发送到打印机。
Edit-Code 因缺乏使用而被取消。
编辑2： 点击此链接：Print html document from Windows Service in C# without print dialog
Vadim 的圣杯解决方案确实有效。但是，它具有仅使用默认打印机等限制。我在打印之前修改了默认打印机，这会导致打印到正确的打印机。我可以看到这里发生了一些并发问题，但到目前为止，这是我想出的最好的（大部分代码来自 Vadim，我完全相信他）：
/// <summary>Provides a scheduler that uses STA threads.</summary>
public sealed class StaTaskScheduler : TaskScheduler, IDisposable
{
/// <summary>Stores the queued tasks to be executed by our pool of STA threads.</summary>
private BlockingCollection<Task> _tasks;
/// <summary>The STA threads used by the scheduler.</summary>
private readonly List<Thread> _threads;
/// <summary>Initializes a new instance of the StaTaskScheduler class with the specified concurrency level.</summary>
/// <param name="numberOfThreads">The number of threads that should be created and used by this scheduler.</param>
public StaTaskScheduler(int numberOfThreads)
{
// Validate arguments
if (numberOfThreads < 1) throw new ArgumentOutOfRangeException("concurrencyLevel");
// Initialize the tasks collection
_tasks = new BlockingCollection<Task>();
// Create the threads to be used by this scheduler
_threads = Enumerable.Range(0, numberOfThreads).Select(i =>
{
var thread = new Thread(() =>
{
// Continually get the next task and try to execute it.
// This will continue until the scheduler is disposed and no more tasks remain.
foreach (var t in _tasks.GetConsumingEnumerable())
{
TryExecuteTask(t);
}
});
thread.IsBackground = true;
thread.SetApartmentState(ApartmentState.STA);
return thread;
}).ToList();
// Start all of the threads
_threads.ForEach(t => t.Start());
}
/// <summary>Queues a Task to be executed by this scheduler.</summary>
/// <param name="task">The task to be executed.</param>
protected override void QueueTask(Task task)
{
// Push it into the blocking collection of tasks
_tasks.Add(task);
}
/// <summary>Provides a list of the scheduled tasks for the debugger to consume.</summary>
/// <returns>An enumerable of all tasks currently scheduled.</returns>
protected override IEnumerable<Task> GetScheduledTasks()
{
// Serialize the contents of the blocking collection of tasks for the debugger
return _tasks.ToArray();
}
/// <summary>Determines whether a Task may be inlined.</summary>
/// <param name="task">The task to be executed.</param>
/// <param name="taskWasPreviouslyQueued">Whether the task was previously queued.</param>
/// <returns>true if the task was successfully inlined; otherwise, false.</returns>
protected override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued)
{
// Try to inline if the current thread is STA
return
Thread.CurrentThread.GetApartmentState() == ApartmentState.STA &&
TryExecuteTask(task);
}
/// <summary>Gets the maximum concurrency level supported by this scheduler.</summary>
public override int MaximumConcurrencyLevel
{
get { return _threads.Count; }
}
/// <summary>
/// Cleans up the scheduler by indicating that no more tasks will be queued.
/// This method blocks until all threads successfully shutdown.
/// </summary>
public void Dispose()
{
if (_tasks != null)
{
// Indicate that no new tasks will be coming in
_tasks.CompleteAdding();
// Wait for all threads to finish processing tasks
foreach (var thread in _threads) thread.Join();
// Cleanup
_tasks.Dispose();
_tasks = null;
}
}
}
public class PrinterHelper
{
readonly TaskScheduler _sta = new StaTaskScheduler(1);
public void PrintHtml(string htmlPath, string printerDevice)
{
if (!string.IsNullOrEmpty(printerDevice))
SetAsDefaultPrinter(printerDevice);
Task.Factory.StartNew(() => PrintOnStaThread(htmlPath), CancellationToken.None, TaskCreationOptions.None, _sta).Wait();
}
static void PrintOnStaThread(string htmlPath)
{
const short PRINT_WAITFORCOMPLETION = 2;
const int OLECMDID_PRINT = 6;
const int OLECMDEXECOPT_DONTPROMPTUSER = 2;
using(var browser = new WebBrowser())
{
browser.Navigate(htmlPath);
while(browser.ReadyState != WebBrowserReadyState.Complete)
Application.DoEvents();
dynamic ie = browser.ActiveXInstance;
ie.ExecWB(OLECMDID_PRINT, OLECMDEXECOPT_DONTPROMPTUSER, PRINT_WAITFORCOMPLETION);
}
}
static void SetAsDefaultPrinter(string printerDevice)
{
foreach (var printer in PrinterSettings.InstalledPrinters)
{
//Verify that the printer exists here
}
var path = "win32_printer.DeviceId='" + printerDevice + "'";
using (var printer = new ManagementObject(path))
{
ManagementBaseObject outParams =
printer.InvokeMethod("SetDefaultPrinter",
null, null);
}
return;
}
}
【问题讨论】：
标签： asp.net-mvc-2 printing c#-4.0