C# Winform实现导出DataGridView当前页以及全部数据

[Description("可导出的最大数量")]
public int ExportMaxCount { get; set; } = 5000;

ContextMenuStrip contextMenuStrip = new ContextMenuStrip();
protected override void OnCreateControl()
{
    base.OnCreateControl();
    contextMenuStrip.Items.Add(new ToolStripMenuItem("导出当前页", null, (s, e) =>
            {
                if (Rows.Count == 0)
                {
                    FrmDialog.ShowMessage("没有数据", "提示");
                    return;
                }
                SaveFileDialog saveFileDialog = new SaveFileDialog();
                saveFileDialog.Filter = "Excel文件|*.xlsx";
                if (saveFileDialog.ShowDialog() == DialogResult.OK)
                {
                    DataTable dt = new DataTable();
                    foreach (DataGridViewColumn column in Columns)
                    {
                        dt.Columns.Add(new DataColumn
                        {
                            ColumnName = column.DataPropertyName,
                            Caption = column.HeaderText
                        });
                    }
                    foreach (DataGridViewRow dr in Rows)
                    {
                        DataRow dataRow = dt.NewRow();
                        for (int i = 0; i < dt.Columns.Count; i++)
                        {
                            dataRow[i] = dr.Cells[i].Value;
                        }
                        dt.Rows.Add(dataRow);
                    }
                    ExcelUtils.Export(dt, saveFileDialog.FileName);
                    if (MessageBox.Show("导出成功，是否打开?", "提示", MessageBoxButtons.YesNo) == DialogResult.Yes)
                    {
                        Process.Start(saveFileDialog.FileName);
                    }
                }
            }));
            this.ContextMenuStrip = contextMenuStrip;

public static void Export(DataTable dataSource, string fileName)
        {
            IWorkbook workbook = new XSSFWorkbook();
            ISheet sheet = workbook.CreateSheet("sheet1");
            IRow rowHead = sheet.CreateRow(0);
            for (int j = 0; j < dataSource.Columns.Count; j++)
            {
                rowHead.CreateCell(j).SetCellValue(dataSource.Columns[j].Caption);
            }
            for (int i = 0; i < dataSource.Rows.Count; i++)
            {
                IRow row = sheet.CreateRow(i + 1);
                for (int j = 0; j < dataSource.Columns.Count; j++)
                {
                    row.CreateCell(j).SetCellValue(Convert.ToString(dataSource.Rows[i][j]));
                }
            }
            using (FileStream fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite))
            {
                workbook.Write(fs);
            }
            workbook.Close();
        }

public EventHandler ExportAllData;
protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);
            if (e.Button == MouseButtons.Right && ExportAllData != null && !contextMenuStrip.Items.ContainsKey("导出全部"))
            {
                contextMenuStrip.Items.Add(new ToolStripMenuItem("导出全部", null, ExportAllData, "导出全部"));
                this.ContextMenuStrip = contextMenuStrip;
            }
        }