if (openFileDialog1.ShowDialog() == DialogResult.OK)
{
 String sConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" +
 "Data Source="+openFileDialog1.FileName+";"+
 "Extended Properties='Excel 8.0;HDR=Yes;IMEX=2'";
 //实例化一个Oledbconnection类(实现了IDisposable,要using)
 using (OleDbConnection ole_conn = new OleDbConnection(sConnectionString))
 {
  ole_conn.Open();
  using (OleDbCommand ole_cmd = ole_conn.CreateCommand())
  {
  //类似SQL的查询语句这个[Sheet1$对应Excel文件中的一个工作表]
  ole_cmd.CommandText = "select * from [Sheet1$]";
  OleDbDataAdapter adapter = new OleDbDataAdapter(ole_cmd);
  DataSet ds = new DataSet();
  adapter.Fill(ds, "Sheet1");
    for (int i = 0; i < ds.Tables[0].Rows.Count; i++)
  {
   MessageBox.Show(ds.Tables[0].Rows[i]["商家名称"].ToString());
  }
  }
 }
}

if (openFileDialog1.ShowDialog() == DialogResult.OK)
{
 String sConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" +
 "Data Source="+openFileDialog1.FileName+";"+
 "Extended Properties='Excel 8.0;HDR=Yes;IMEX=2'";
 //实例化一个Oledbconnection类(实现了IDisposable,要using)
 using (OleDbConnection ole_conn = new OleDbConnection(sConnectionString))
 {
  ole_conn.Open();
  using (OleDbCommand ole_cmd = ole_conn.CreateCommand())
  {
  DataTable tb = ole_conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
  foreach (DataRow row in tb.Rows)
  {
   MessageBox.Show(row["TABLE_NAME"].ToString());
  }
  }
 }
}

if (openFileDialog1.ShowDialog() == DialogResult.OK)
{
 String sConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" +
 "Data Source="+openFileDialog1.FileName+";"+
 "Extended Properties=Excel 8.0;";
 //实例化一个Oledbconnection类(实现了IDisposable,要using)
 using (OleDbConnection ole_conn = new OleDbConnection(sConnectionString))
 {
  ole_conn.Open();
  using (OleDbCommand ole_cmd = ole_conn.CreateCommand())
  {
  ole_cmd.CommandText = "insert into [Sheet1$](商户ID,商家名称)values('DJ001','点击科技')";
  ole_cmd.ExecuteNonQuery();
  MessageBox.Show("数据插入成功......");
  }
 }
}

String sConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" +
  "Data Source=d:\\excel1.xls;" +
  "Extended Properties=Excel 8.0;";
 //实例化一个Oledbconnection类(实现了IDisposable,要using)
 using (OleDbConnection ole_conn = new OleDbConnection(sConnectionString))
 {
  ole_conn.Open();
  using (OleDbCommand ole_cmd = ole_conn.CreateCommand())
  {
  ole_cmd.CommandText = "CREATE TABLE CustomerInfo ([CustomerID] VarChar,[Customer] VarChar)";
  ole_cmd.ExecuteNonQuery();
  ole_cmd.CommandText = "insert into CustomerInfo(CustomerID,Customer)values('DJ001','点击科技')";
  ole_cmd.ExecuteNonQuery();
  MessageBox.Show("生成Excel文件成功并写入一条数据......");
  }
}