PrintDocument.PrintPage的PrintPreviewDialog调用中的字符串长度限制

Question

将VS Community 2017与.NET Framework 4.6一起使用。

以下代码摘自MS文档，适用于打印到打印机，但在PrintPreviewDialog调用中有限制。

string text;
string ToPrint;
private void PrintDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
    int charactersOnPage = 0;
    int linesPerPage = 0;

    // Sets the value of charactersOnPage to the number of characters
    // of stringToPrint that will fit within the bounds of the page.
    e.Graphics.MeasureString(ToPrint, this.Font,
        e.MarginBounds.Size, StringFormat.GenericTypographic,
        out charactersOnPage, out linesPerPage);
    // Draws the string within the bounds of the page.
    e.Graphics.DrawString(ToPrint, this.Font, Brushes.Black,
        e.MarginBounds, StringFormat.GenericTypographic);

    // Remove the portion of the string that has been printed.
    ToPrint = ToPrint.Substring(charactersOnPage);

    // Check to see if more pages are to be printed.
    e.HasMorePages = (ToPrint.Length > 0);

    // If there are no more pages, reset the string to be printed.
    if (!e.HasMorePages)
        ToPrint = text;
}

经过试验，我发现如果“ ToPrint”字符串的长度大于32490个字符，则e.Graphics.DrawString会生成空白的打印预览页。

有人知道这是为什么吗？我缺少某些设置或选项吗？

谢谢