public class PersonCollection : IEnumerable, IEnumerator
{
    private Person[] _collection;

    public PersonCollection(Person[] collection)
    {
        _collection = new Person[collection.Length];

        for (int i = 0; i < collection.Length; i++)
            _collection[i] = collection[i];
    }

    //IEnumerable实现部分

    public IEnumerator GetEnumerator()
    {
        return (IEnumerator)this;
    }

    //IEnumerator实现部分

    private int position = -1;
    public bool MoveNext()
    {
        position++;
        return (position < _collection.Length);
    }

    public void Reset()
    {
        position = -1;
    }

    public object Current
    {
        get
        {
            try
            {
                return _collection[position];
            }
            catch (IndexOutOfRangeException)
            {
                throw new InvalidOperationException();
            }
        }
    }
}

Person[] list = new Person[]{
    new Person("张三",20),
    new Person("李四",21),
    new Person("王五",22)
};
PersonCollection collect = new PersonCollection(list);

foreach (Person person in collect)
    MessageBox.Show(person.Name + "," + person.Age);

using System;
using System.Data;
using System.Data.SqlClient;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            //dataGridView1配置
            dataGridView1.AllowUserToAddRows = true;
            dataGridView1.AllowUserToDeleteRows = true;
            dataGridView1.ReadOnly = false;
            dataGridView1.Columns["ProductID"].ReadOnly = true;

            //数据绑定
            using (SqlConnection conn = new SqlConnection("server=(local);database=Test;user id=sa;password=sa;"))
            {
                using (SqlDataAdapter adapter = new SqlDataAdapter("Select * FROM Products orDER BY ProductID DESC", conn))
                {
                    DataTable table = new DataTable();
                    adapter.Fill(table);

                    dataGridView1.DataSource = table;
                }
            }
        }

        /// <summary>
        /// 提交更新
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void button1_Click(object sender, EventArgs e)
        {
            if (dataGridView1.DataSource != null)
            {
                DataRow row;
                DataTable table = (DataTable)dataGridView1.DataSource;
                int count = table.Rows.Count;
                int newid = 0;

                using (SqlConnection conn = new SqlConnection("server=(local);database=Test;user id=sa;password=sa;"))
                {
                    SqlCommand cmd;
                    conn.Open();

                    for (int i = 0; i < count; i++)
                    {
                        row = table.Rows[i];

                        if (row.RowState != DataRowState.Unchanged)
                        {
                            //添加
                            if (row.RowState == DataRowState.Added)
                            {
                                using (cmd = new SqlCommand("Insert INTO Products(ProductName,Price,Num,PriceSUM) VALUES(@ProductName,@Price,@Num,@PriceSUM);Select SCOPE_IDENTITY();", conn))
                                {
                                    cmd.Parameters.Add("@ProductName", SqlDbType.NVarChar, 20);
                                    cmd.Parameters.Add("@Price", SqlDbType.Money, 10);
                                    cmd.Parameters.Add("@Num", SqlDbType.Int, 10);
                                    cmd.Parameters.Add("@PriceSUM", SqlDbType.Money, 10);

                                    cmd.Parameters["@ProductName"].Value = row["ProductName"];
                                    cmd.Parameters["@Price"].Value = row["Price"];
                                    cmd.Parameters["@Num"].Value = row["Num"];
                                    cmd.Parameters["@PriceSUM"].Value = row["PriceSUM"];

                                    newid = Convert.ToInt32(cmd.ExecuteScalar());
                                    row["ProductID"] = newid;
                                }
                            }
                            //修改
                            else if (row.RowState == DataRowState.Modified)
                            {
                                using (cmd = new SqlCommand("Update Products SET ProductName=@ProductName,Price=@Price,Num=@Num,PriceSUM=@PriceSUM Where ProductID=@ProductID", conn))
                                {
                                    cmd.Parameters.Add("@ProductName", SqlDbType.NVarChar, 20);
                                    cmd.Parameters.Add("@Price", SqlDbType.Money, 10);
                                    cmd.Parameters.Add("@Num", SqlDbType.Int, 10);
                                    cmd.Parameters.Add("@PriceSUM", SqlDbType.Money, 10);
                                    cmd.Parameters.Add("@ProductID", SqlDbType.Int, 10);

                                    cmd.Parameters["@ProductName"].Value = row["ProductName"];
                                    cmd.Parameters["@Price"].Value = row["Price"];
                                    cmd.Parameters["@Num"].Value = row["Num"];
                                    cmd.Parameters["@PriceSUM"].Value = row["PriceSUM"];
                                    cmd.Parameters["@ProductID"].Value = row["ProductID", DataRowVersion.Original];//取修改前的值

                                    cmd.ExecuteNonQuery();
                                }
                            }
                            //删除
                            else if (row.RowState == DataRowState.Deleted)
                            {
                                using (cmd = new SqlCommand("Delete FROM Products Where ProductID=@ProductID", conn))
                                {
                                    cmd.Parameters.Add("@ProductID", SqlDbType.Int, 10);

                                    cmd.Parameters["@ProductID"].Value = row["ProductID", DataRowVersion.Original];

                                    cmd.ExecuteNonQuery();
                                }
                            }
                        }
                    }

                    conn.Close();

                    table.AcceptChanges();
                }
            }
        }
    }
}

using System;
using System.Data;
using System.Data.SqlClient;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        private SqlDataAdapter _adapter;
        private DataTable _table;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection("Data Source=127.0.0.1;Initial Catalog=Test;User ID=sa;Password=sa");
            _adapter = new SqlDataAdapter("Select * FROM Products", conn);
            SqlCommandBuilder builder = new SqlCommandBuilder(_adapter);//自动生成InsertCommand、UpdateCommand和DeleteCommand

            _table = new DataTable();
            _adapter.Fill(_table);

            dataGridView1.DataSource = _table;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            _adapter.Update(_table);
        }
    }
}