如何在**保持自定义货币格式**的同时，使用iTextSharp将C# DataGridView导出为PDF？

using System;
using System.IO;
using System.Windows.Forms;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace DataGridViewToPDF
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnExport_Click(object sender, EventArgs e)
        {
            // 创建PDF文档
            Document document = new Document();
            PdfWriter writer = PdfWriter.GetInstance(document, new FileStream("output.pdf", FileMode.Create));
            document.Open();

            // 创建PDF表格
            PdfPTable table = new PdfPTable(dataGridView1.Columns.Count);
            table.DefaultCell.Padding = 3;
            table.WidthPercentage = 100;
            table.HorizontalAlignment = Element.ALIGN_LEFT;

            // 添加表头
            foreach (DataGridViewColumn column in dataGridView1.Columns)
            {
                PdfPCell cell = new PdfPCell(new Phrase(column.HeaderText));
                table.AddCell(cell);
            }

            // 添加数据行
            foreach (DataGridViewRow row in dataGridView1.Rows)
            {
                foreach (DataGridViewCell cell in row.Cells)
                {
                    if (cell.Value != null)
                    {
                        // 格式化货币数据
                        if (cell.ValueType == typeof(decimal))
                        {
                            cell.Value = ((decimal)cell.Value).ToString("C");
                        }

                        table.AddCell(cell.Value.ToString());
                    }
                }
            }

            // 将表格添加到PDF文档
            document.Add(table);
            document.Close();

            MessageBox.Show("导出成功！");
        }
    }
}