在使用iTextSharp创建PDF的过程中，如何获取PDF页面中最后写入的数据位置？

Question

我正在使用iTextSharp将数百张表一个接一个地添加到PDF文档中。 但这是我们不知道何时创建新页面的问题。 有时表的一半转到下一页，而另一半保留在当前页中。有什么方法可以使我有最后写入的位置，以便我可以决定是否创建新页面。

我在StackOverFlow上找到了一些代码，但没有一个对我有用。 在将新数据添加到文档之前，我尝试使用以下代码获取位置。

float y = PdfPageHeight; 
for(int i=0;i<100;i++)
{
    if(y<=document.document.BottomMargin)
    {
      document.NewPage();
    }
    mainTableHeader = new PdfPTable(1);
    mainTableHeader.SetWidthPercentage(new float[] { PageSize.A4.Width }, PageSize.A4);
    AddContent(ref mainTableHeader); //Adding some cells to the table
    document.Add(mainTableHeader);
    y=writer.GetVerticalPosition(false);
} 

如果有人知道该怎么做，请帮助我。

Answer 1

我对代码进行了一些小的更改（将未知的方法AddContent替换为代码，实际上将一些单元格添加到了表中 ；添加了一些Console输出）：

using (Document document = new Document())
{
    PdfWriter writer = PdfWriter.GetInstance(document, new FileStream(dest, FileMode.Create, FileAccess.Write));
    document.Open();

    float y = document.PageSize.Height;
    for (int i = 0; i < 100; i++)
    {
        if (y <= document.BottomMargin)
        {
            Console.Write("New Page!\n");
            document.NewPage();
        }
        PdfPTable mainTableHeader = new PdfPTable(1);
        mainTableHeader.SetWidthPercentage(new float[] { PageSize.A4.Width }, PageSize.A4);
        mainTableHeader.AddCell("Test");
        mainTableHeader.AddCell(writer.GetVerticalPosition(false).ToString());
        mainTableHeader.AddCell(writer.GetVerticalPosition(false).ToString());
        document.Add(mainTableHeader);
        y = writer.GetVerticalPosition(false);
        Console.Write("After table {0} y is at {1}\n", i, y);
    } 
}

运行下面在控制台上看到的代码：

After table 0 y is at 758
After table 1 y is at 710
After table 2 y is at 662
After table 3 y is at 614
After table 4 y is at 566
After table 5 y is at 518
After table 6 y is at 470
After table 7 y is at 422
After table 8 y is at 374
After table 9 y is at 326
After table 10 y is at 278
After table 11 y is at 230
After table 12 y is at 182
After table 13 y is at 134
After table 14 y is at 86
After table 15 y is at 38
After table 16 y is at 758
After table 17 y is at 710
After table 18 y is at 662
After table 19 y is at 614
After table 20 y is at 566
After table 21 y is at 518
After table 22 y is at 470
After table 23 y is at 422
After table 24 y is at 374
After table 25 y is at 326
After table 26 y is at 278
After table 27 y is at 230
After table 28 y is at 182
After table 29 y is at 134
After table 30 y is at 86
After table 31 y is at 38
After table 32 y is at 758
After table 33 y is at 710
After table 34 y is at 662
After table 35 y is at 614
After table 36 y is at 566
After table 37 y is at 518
After table 38 y is at 470
After table 39 y is at 422
After table 40 y is at 374
After table 41 y is at 326
After table 42 y is at 278
After table 43 y is at 230
After table 44 y is at 182
After table 45 y is at 134
After table 46 y is at 86
After table 47 y is at 38
After table 48 y is at 758
After table 49 y is at 710
After table 50 y is at 662
After table 51 y is at 614
After table 52 y is at 566
After table 53 y is at 518
After table 54 y is at 470
After table 55 y is at 422
After table 56 y is at 374
After table 57 y is at 326
After table 58 y is at 278
After table 59 y is at 230
After table 60 y is at 182
After table 61 y is at 134
After table 62 y is at 86
After table 63 y is at 38
After table 64 y is at 758
After table 65 y is at 710
After table 66 y is at 662
After table 67 y is at 614
After table 68 y is at 566
After table 69 y is at 518
After table 70 y is at 470
After table 71 y is at 422
After table 72 y is at 374
After table 73 y is at 326
After table 74 y is at 278
After table 75 y is at 230
After table 76 y is at 182
After table 77 y is at 134
After table 78 y is at 86
After table 79 y is at 38
After table 80 y is at 758
After table 81 y is at 710
After table 82 y is at 662
After table 83 y is at 614
After table 84 y is at 566
After table 85 y is at 518
After table 86 y is at 470
After table 87 y is at 422
After table 88 y is at 374
After table 89 y is at 326
After table 90 y is at 278
After table 91 y is at 230
After table 92 y is at 182
After table 93 y is at 134
After table 94 y is at 86
After table 95 y is at 38
After table 96 y is at 758
After table 97 y is at 710
After table 98 y is at 662
After table 99 y is at 614

因此，您在评论中声称

每次我计算“ y”值时，它都保持不变

要么

每次我向文档添加新表时都使用该表。 每次我获得相同的价值。

无法用您的代码复制： y一直在疯狂地变化。

因此，如果您需要帮助，请提供示例代码，以使人们重现您的问题，而不是反驳您的主张。