using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data;
using System.Data.OleDb;

namespace WindowsFormsApplication7
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        public static DataSet GetExcelData(string str)
        {
            string strCon = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + str + ";Extended Properties=‘Excel 12.0;HDR=YES;IMEX=1;‘";
            OleDbConnection myConn = new OleDbConnection(strCon);
            string strCom = " SELECT * FROM [Sheet1$]";
            myConn.Open();
            OleDbDataAdapter myCommand = new OleDbDataAdapter(strCom, myConn);
            DataSet myDataSet = new DataSet();
            myCommand.Fill(myDataSet, "[Sheet1$]");
            myConn.Close();
            return myDataSet;
        }  
        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog filedialog = new OpenFileDialog();
            string FileName = "";

            if (filedialog.ShowDialog() == DialogResult.OK)
            {
                FileName = filedialog.FileName;

                dGViewExcel.DataSource = GetExcelData(FileName);
                dGViewExcel.DataMember = "[Sheet1$]";

                for (int count = 0; (count <= (dGViewExcel.Rows.Count - 1)); count++)
                {

                    dGViewExcel.Rows[count].HeaderCell.Value = (count + 1).ToString();

                }
            }
        }
    }
}

C#讀取excel文件到DATAVIEW