中断保存操作挂起

不幸的是，在文档保存期间，应用程序可能会挂起并停止响应。此功能允许您优雅地取消长时间运行的操作，例如保存大型或复杂的 PDF 文档，从而防止应用程序冻结并提高响应能力。您将找到将此功能集成到应用程序中的相关信息。请注意，这种方法确保您的应用程序在资源密集型操作期间仍然保持响应。

‘InterruptMonitor’ 类提供了中断文档保存过程的能力，如果该过程耗时过长。(https://reference.aspose.com/pdf/zh/net/aspose.pdf.forms/form/properties/xfa)。

以下代码片段也适用于 Aspose.PDF.Drawing 库。

使用 InterruptMonitor

让我们强调实现涉及几个关键步骤：

InterruptMonitor 创建： 实例化一个 InterruptMonitor 对象。该对象充当线程中断的信号。
ThreadLocalInstance 分配： 在启动长时间运行的 Aspose.PDF 操作之前，将 InterruptMonitor 实例分配给当前线程的 InterruptMonitor.ThreadLocalInstance。这将监视器链接到线程。
线程执行： 在单独的线程中执行包含 Aspose.PDF 操作的代码（例如，Document.Save()）。
中断信号： 在合适的时机（例如，超时或用户操作后），调用 monitor.Interrupt()。这会向线程发出终止的信号。
异常处理： 如果被中断，Document.Save() 方法会抛出 OperationCanceledException。使用 try-catch 块处理此异常。请记住，适当的异常处理对于应用程序的稳定性至关重要。

以下代码片段向您展示如何在 PDF 处理过程中使用 InterruptMonitor。

.NET Core 3.1

// For complete examples and data files, visit https://github.com/aspose-pdf/Aspose.PDF-for-.NET
private static void InterruptMonitorExample()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_Text();
    // Path to a large text file 
    var longTextFile = dataDir + "LongTextFile.txt";
    var outputFile = dataDir + "interrupt_output.pdf";
    var longText = File.ReadAllText(longTextFile);

    // Create an InterruptMonitor instance
    using (var monitor = new InterruptMonitor())
    {
        // Create a RowSpanWorker instance, passing the monitor
        var worker = new RowSpanWorker(outputFile, monitor, longText);

        // Start the worker thread
        var thread = new Thread(worker.Work);
        thread.Start();

        // Simulate a timeout (adjust as needed)
        Thread.Sleep(500);

        // Interrupt the thread
        monitor.Interrupt();

        // Wait for the thread to finish
        thread.Join();
    }
}

// Helper class to demonstrate how to handle PDF generation with interruption support
private class RowSpanWorker
{
    private readonly string outputPath;
    private readonly string longText;
    private readonly Aspose.Pdf.Multithreading.InterruptMonitor monitor;

    public RowSpanWorker(string outputPath, Aspose.Pdf.Multithreading.InterruptMonitor monitor, string longText)
    {
        this.outputPath = outputPath;
        this.monitor = monitor;
        this.longText = longText;
    }

    public void Work()
    {
        // Create PDF document
        using (var document  = new Aspose.Pdf.Document())
        {
            // Assign the InterruptMonitor to the current thread
            Aspose.Pdf.Multithreading.InterruptMonitor.ThreadLocalInstance = this.monitor;
            var page = document.Pages.Add();

            var table = new Aspose.Pdf.Table
            {
                DefaultCellBorder = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, 0.1F)
            };

            var row0 = table.Rows.Add();

            // Add a cell spanning multiple rows with long text
            var cell00 = row0.Cells.Add(this.longText);
            cell00.RowSpan = 2;
            cell00.IsWordWrapped = true;
            row0.Cells.Add("Ipsum Ipsum Ipsum");
            row0.Cells.Add("Dolor Dolor Dolor");

            var row1 = table.Rows.Add();
            row1.Cells.Add("Ipsum Dolor");
            row1.Cells.Add("Dolor Dolor");

            page.Paragraphs.Add(table);

            try
            {
                // Save the document (this operation can be interrupted)
                document.Save(this.outputPath);
            }
            catch (OperationCanceledException ex)
            {
                Console.WriteLine($"Operation cancelled: {ex.Message}");
            }
        }
    }
}

.NET 8

private static void InterruptMonitorExample()
{
    // The path to the documents directory
    var dataDir = RunExamples.GetDataDir_AsposePdf_Text();

    // Construct a long text string to simulate a long process
    var longTextFile = Path.Combine(dataDir, "LongTextFile.txt");
    var outputFile = Path.Combine(dataDir, "interrupt_output.pdf");
    var longText = File.ReadAllText(longTextFile);

    // Create an InterruptMonitor instance
    using Aspose.Pdf.Multithreading.InterruptMonitor monitor = new();

    // Create a RowSpanWorker instance, passing the monitor
    var worker = new RowSpanWorker(outputFile, monitor, longText);

    // Start the worker thread
    var thread = new Thread(worker.Work);
    thread.Start();

    // Simulate a timeout (adjust as needed)
    Thread.Sleep(500);

    // Interrupt the thread
    monitor.Interrupt();

    // Wait for the thread to finish
    thread.Join();    
}

// Helper class to demonstrate how to handle PDF generation with interruption support
public class RowSpanWorker
{
    private readonly string _outputFile;
    private readonly InterruptMonitor _monitor;
    private readonly string _longText;

    public RowSpanWorker(string outputFile, Aspose.Pdf.Multithreading.InterruptMonitor monitor, string longText)
    {
        _outputFile = outputFile;
        _monitor = monitor;
        _longText = longText;
    }

    public void Work()
    {
        // Create PDF document
        using Aspose.Pdf.Document document = new();

        // Assign the InterruptMonitor to the current thread
        Aspose.Pdf.Multithreading.InterruptMonitor.ThreadLocalInstance = this._monitor;
        var page = document.Pages.Add();

        var table = new Aspose.Pdf.Table
        {
            DefaultCellBorder = new Aspose.Pdf.BorderInfo(Aspose.Pdf.BorderSide.All, 0.1F)
        };

        var row0 = table.Rows.Add();

        // Add a cell spanning multiple rows with long text
        var cell00 = row0.Cells.Add(this._longText);
        cell00.RowSpan = 2;
        cell00.IsWordWrapped = true;
        row0.Cells.Add("Ipsum Ipsum Ipsum Ipsum Ipsum Ipsum ");
        row0.Cells.Add("Dolor Dolor Dolor Dolor Dolor Dolor ");

        var row1 = table.Rows.Add();
        row1.Cells.Add("IpsumDolor Dolor Dolor Dolor Dolor ");
        row1.Cells.Add("DolorDolor Dolor Dolor Dolor Dolor ");

        page.Paragraphs.Add(table);
        try
        {
            //Save() operation supports interruption 
            document.Save(this._outputFile);
        }
        catch (OperationCanceledException ex)
        {
            //print operation cancel exception's message to console 
            Console.WriteLine(ex.Message);
        }
    }
}

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