C# WinForm【DataTable分页查询与数据导出到Excel】

准备：主要控件
saveFileDialog 保存文件
bindingNavigator 分页控件
bindingSource 绑定数据源
引用命名空间

using System;
using System.Data;
using System.Windows.Forms;
using Excel = Microsoft.Office.Interop.Excel;
using System.Data.SqlClient;
namespace CancelCardID
{
   
	public partial class CancelCardID:Form
	{
   
	   private SqlDataAdapter pagingDA;
       private DataSet pagingDS = new DataSet();
       private int StarVal = 0;//起始值；
       private int valPerPage = 3;//每页显示的条数；
       private int totalValNumber;//总条数；
       private int totalPageNumber;//总页数；
       private int currentPage = 1;
       
       public CancelCardID()
		{
   
		    InitializeComponent();
        }
        
       private void CancelCardID_Load(object sender, EventArgs e)
       {
   
			bindingNavigator1.Visible = false;
	   }

		private void btnQuery_Click(object sender,EventArgs e)
		{
   
			lblMsg.Text = "";
			GV1.DataSource = null;
			string sql = "select EmpID,EmpName,InvalidCardID,DeviceID,InvalidDayID from Card_Invalid where InvalidDayID between '"
			+sDayID.Text+"' and '"+eDayID.Text+"'";

			#region 1.检查日期是否正确
			//A.检查开始日期
			string v_sdayid = sDayID.Text;
			if(v_sdayid.Length !=10)
			{
   
				lblMsg.Text = "日期格式不合法！！！";
				lbl.Msg.ForeColor = System.Drawing.Color.Red;
				return;
			}
			DateTime chk_sdate;
			try
			{
   
				chk_sdate = Convert.ToDateTime(v_sdayid);
			}
			catch(Exception)
			{
   
				lblMsg.Text = "日期格式不合法！！！";
				lblMsg.ForeColor = System.Drawing.Color.Red;
				return;
			}
			//B.检查结束日期
			string v_edayid = eDayID.Text;
			if(v_edayid.Length != 10)
			{
   
				lblMsg.Text = "日期格式不合法！！！";
				lblMsg.ForeColor = System.Drawing.Color.Red;
				Red;
			}
			DateTime chk_edate;
			try
			{
   
				chk_edate = Convert.ToDateTime(v_edayid);
			}
			catch(Exception)
			{
   
				lblMsg.Text = "日期格式不合法！！！";
				lblbMsg.ForeColor = System.Drawing.Color.Red;
				return;
			}
			//C.开始日期结束日期比对
			if(Convert.ToDateTime(v_sdayid))>(Convert.ToDateTime(edayid))
			{
   
				lblMsg.Text = "开始时间不能大于结束时间！！！";
				lblMsg.ForeColor = System.Drawing.Color.Red;
				return;
			}
			//D.规定查询日期区间
			TimeSpan span = DateTime.Parse(eDayID.Text).Subtract(DateTime.Parse(sDayID.Text));