使用ADO.NET操作Excel

private void btnSelectFile_Click(object sender, EventArgs e)
        {
            //打开文件对话框。
            OpenFileDialog openFile = new OpenFileDialog();
            //后缀名。
            openFile.Filter = "Excel文件(*.xls,*.xlsx)|*.xls;*.xlsx";
            if (openFile.ShowDialog() == DialogResult.OK)
            {
                try
                {
                    //文件名包含路径
                    string filename = openFile.FileName;
                    txtExcelName.Text = filename;
                    //sql语句
                    string sql = "select * from [Sheet1$]";
                    //数据库连接字符串
                    string connStr = "Provider=Microsoft.Jet.OLEDB.4.0;Extended Properties=Excel 8.0;data source=" + filename;
                    //如果是2007格式
                    if (filename.ToUpper().EndsWith("XLSX"))
                    {
                       connStr= "Provider=Microsoft.ACE.OLEDB.12.0;Extended Properties=Excel 12.0;data source=" + filename;
                    }
                    DataSet ds = SqlHelper.ExecuteDataset(connStr, sql, CommandType.Text);

                    dgvCurrent.DataSource = ds.Tables[0].DefaultView;
                    lblcount.Text = ds.Tables[0].Rows.Count.ToString();
                }
                catch (Exception err)
                {
                    MessageBox.Show("错误：" + err.Message);
                }
            }
        }