C#新手之控制項資料繫結

我是個C#新手，最近有個程式要把TextBox的Text屬性與一個int屬性綁定，發現一個奇怪的事，在一個屬性中更改另一個屬性，TextBox控制項顯示的值就可以自動更新，但用點擊按鈕的方法就無效。代碼：

用於示範的類Class1：

using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace WindowsFormsApplication3{    class Class1    {        private int _a = 1;        public int A        {            get { return _a; }            set             {                if (_a != value)                {                    _b = value + 1;                    _a = value;                 }            }        }        private int _b = 2;        public int B        {            get { return _b; }            set { _b = value; }        }    }}

當A的值改變時，B變為A+1。

介面：

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;namespace WindowsFormsApplication3{    public partial class Form1 : Form    {        private Class1 _class1 = new Class1();        private TextBox tbA;        private TextBox tbB;        private Button button1;        public Form1()        {            tbA = new TextBox();  //與A綁定            tbB = new TextBox();  //與B綁定            button1 = new Button();                        tbA.Location = new Point(105, 39);            tbA.Name = "tbA";            tbA.Size = new Size(121, 21);                        tbB.Location = new Point(106, 118);            tbB.Name = "tbB";            tbB.Size = new Size(119, 21);                        button1.Location = new Point(148, 67);            button1.Name = "button1";            button1.Size = new Size(23, 45);            button1.TabIndex = 2;            button1.Text = "B加1";            button1.Click += new System.EventHandler(button1_Click);            this.Controls.Add(this.button1);            this.Controls.Add(this.tbB);            this.Controls.Add(this.tbA);            tbA.DataBindings.Add("Text", _class1, "A");            tbB.DataBindings.Add("Text", _class1, "B");        }        private void button1_Click(object sender, EventArgs e)        {            _class1.B += 1;        }    }}

在tbA中改變數值後按tab，tbB中的數值會自動更新。但點button1後B的值實際上是改變的，但控制項中不會更新，除非用INotifyPropertyChanged。

public int B        {            get { return _b; }            set            {                _b = value;                NotifyPropertyChanged("B");            }        }        #region INotifyPropertyChanged 成員        public event PropertyChangedEventHandler PropertyChanged;        public void NotifyPropertyChanged(string ProName)        {            if (PropertyChanged != null)            {                PropertyChanged(this, new PropertyChangedEventArgs(ProName));            }        }        #endregion

具體原因就是因為DataBindings方法綁定是有聯動效果的,你要手動賦值就不行
tbA.Text=_class1.A;