关于在DataGrid里添加ComboBox（一）

这段代码我没整理过，希望哪位整理一下重新贴上来
using System;
using System.Data;
using System.Drawing;
using System.Collections;
using System.Globalization;
using System.Windows.Forms;
using System.ComponentModel;
using System.Data.SqlClient;
namespace ComboBoxInDataGrid
{
    public class Form2:System.Windows.Forms.Form
    {
        ///
        /// Required designer variable.
        ///
        private SqlDataAdapter sqlDA;
        private SqlCommand sqlSelectStudent;
        private SqlCommand sqlInsertStudent;
        private SqlCommand sqlUpdateStudent;
        private SqlCommand sqlDeleteStudent;
        private System.ComponentModel.Container components = null;
        private string StrSQL;
        private SqlConnection sqlConn;
        private DataSet _StudentDS;
        private DataTable _CourseDT;
        private DataGridTableStyle GridTableStyle;