c# datagridview绑定数据源（BindingList<class>）中的现象 待查

现象1：

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;

namespace datagridview

{

    public partial class Form1 : Form

    {

        public Int32 count = 0;

        public string str = "test!";

        BindingList<Item> items = new BindingList<Item>();

        public Form1()

        {

            InitializeComponent();

            //禁止自动创建列

            this.dataGridView1.AutoGenerateColumns = false;

            //将左边的一栏去掉

            this.dataGridView1.RowHeadersVisible = false;

            //允许用户交换列

            this.dataGridView1.AllowUserToOrderColumns = true;

            this.dataGridView1.DataSource = items;

            //创建“序号”列

            DataGridViewTextBoxColumn serial = new DataGridViewTextBoxColumn();

            serial.HeaderText = "序号";

            serial.DataPropertyName = "Serial";

            this.dataGridView1.Columns.Add(serial);

            //创建“文本”列

            DataGridViewTextBoxColumn text = new DataGridViewTextBoxColumn();

            text.HeaderText = "文本";

            text.DataPropertyName = "Text";

            this.dataGridView1.Columns.Add(text);

        }

        private void button1_Click(object sender, EventArgs e)

        {

        }

        private void button2_Click(object sender, EventArgs e)

        {

            items.Add(new Item(str, count++));

            //items.Add(new Item(0) { Text = str, Serial = count++ });

            //有时候使用DataGridView难免会在最后插入一条数据，如果插入的数据超过滚动条显示的行数，

            //那么默认情况下不会显示到最后一行。增加以下代码一直将滚动条拉倒最低。

            this.dataGridView1.FirstDisplayedScrollingRowIndex = this.dataGridView1.Rows.Count - 1;

        }

    }

    class Item

    {

        private string _text;

        private int _serial;

        public string Text

        {

            get { return _text; }

        }

        public int Serial

        {

            get { return _serial; }

        }

        public Item(string text, int serial)

        {

            this._text = text;

            this._serial = serial;

        }

        //public string Text { get; set; }

        //public int Serial { get; set; }

        //public Item(int serial)

        //{

        //    int a = 0;

        //}

    }

}

运行结果：

当在Item类中增加默认构造函数后：

    class Item

    {

        private string _text;

        private int _serial;

        public string Text

        {

            get { return _text; }

        }

        public int Serial

        {

            get { return _serial; }

        }

        public Item(string text, int serial)

        {

            this._text = text;

            this._serial = serial;

        }

        public Item()

        {

            int a = 0;

        }

运行结果：

显示最后一栏空白，原因未知待查！