我正在使用一个Windows服务，并且希望在服务启动时打印一个.html页面。 我正在使用这段代码并且它可以正常打印。 但是会出现一个打印对话框，如何在不弹出打印对话框的情况下打印呢？
public void printdoc(string document)
{
Process printjob = new Process();
printjob.StartInfo.FileName = document;
printjob.StartInfo.UseShellExecute = true;
printjob.StartInfo.Verb = "print";
printjob.StartInfo.CreateNoWindow = true;
printjob.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
printjob.Start();
}
有没有其他方法可以打印而不显示打印对话框。
提前致谢， Anup Pal
这里是圣杯。
利用 StaTaskScheduler（从Parallel Extension Extras中获取（Code Gallery上的发布））。
功能：等待打印完成，不显示打印设置，希望可靠。
限制：需要C# 4.0，使用默认打印机，不允许更改打印模板。
TaskScheduler Sta = new StaTaskScheduler(1);
public void PrintHtml(string htmlPath)
{
Task.Factory.StartNew(() => PrintOnStaThread(htmlPath), CancellationToken.None, TaskCreationOptions.None, Sta).Wait();
}
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);
}
}
//--------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// File: StaTaskScheduler.cs
//
//--------------------------------------------------------------------------
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
namespace System.Threading.Tasks.Schedulers
{
/// <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;
}
}
}
}
除了Vadim的限制，您还可以在打印之前使用以下方法设置默认打印机：
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))
{
printer.InvokeMethod("SetDefaultPrinter",
null, null);
}
return;
}
稍微更改PrintHtml方法：
public void PrintHtml(string htmlPath, string printerDevice)
{
if (!string.IsNullOrEmpty(printerDevice))
SetAsDefaultPrinter(printerDevice);
Task.Factory.StartNew(() => PrintOnStaThread(htmlPath), CancellationToken.None, TaskCreationOptions.None, _sta).Wait();
}
我不确定在大量打印环境中这样做会出现并发问题，因为改变默认打印机可能会带来一些问题。但目前这是我想到的最好的解决方法。