C#winform打印excel问题

Question

利用excel作为固定模板，VS2010 C/S往excel固定的单元格添加数据，添加数据后通过C/S程序打印excel，打印完成后再把打印前添加

的数据清空（全程不手动操作excel 全是有C/S程序执行）。这个是能打印成功的而且不报错。 但假如一张模板能打印5行数据，实际

有超过5条数据，这就涉及到多页打印，多页打印后就会报错 如图所示
Microsoft.Office.Interop.Excel.Application xlApp = new Microsoft.Office.Interop.Excel.Application();
System.Data.DataTable dt = dataGridView1.DataSource as System.Data.DataTable;
xlApp.Visible = false;
xlApp.UserControl = true;
xlApp.DisplayAlerts = false;
Microsoft.Office.Interop.Excel.Workbooks workbooks = xlApp.Workbooks;
Microsoft.Office.Interop.Excel.Workbook workbook = workbooks.Add(strFilePath); //目标文件
Microsoft.Office.Interop.Excel.Worksheet worksheet =

(Microsoft.Office.Interop.Excel.Worksheet)workbook.Worksheets[1];//取得sheet1
for (int cishu = 1; cishu <= q; cishu++)
{
if (dataGridView1.Rows.Count >= 5)
{
jj = 5;
}
else
{
jj = dataGridView1.Rows.Count;
}
for (int i = 0; i < jj; i++)
{

worksheet.Cells[8 + i, 1] = dt.Rows[i]["ClName"].ToString();
worksheet.Cells[8 + i, 4] = dt.Rows[i]["SpecifiCations"].ToString();
worksheet.Cells[8 + i, 7] = dt.Rows[i]["Company"].ToString();
worksheet.Cells[8 + i, 8] = dt.Rows[i]["Number"].ToString();

}
}
System.Windows.Forms.Application.DoEvents();
xlApp.DisplayAlerts = false;
xlApp.Visible = false;
worksheet = null;
workbook = null;
workbooks = null;
xlApp.WindowState = Microsoft.Office.Interop.Excel.XlWindowState.xlNormal;
xlApp.Width = xlApp.Height = 0;
xlApp.Dialogs[Microsoft.Office.Interop.Excel.XlBuiltInDialog.xlDialogPrint].Show();
xlApp.Application.Quit();
xlApp.Quit();
System.Runtime.InteropServices.Marshal.ReleaseComObject(xlApp);
GC.Collect();

Answer 1

dt.Rows[i]["ClName"]?.ToString();