VS2003和VS2005下文本框的只能输入数字类型的区别

    前几天在做项目时,分别用03和05做,发现在判别文本框检验只能输入数字类型的数字时,在 TextBox_KeyPress事件中e.keychar的属性有所区别,在VS2003下,是只读的,而在VS2005下是既可读又可写.所以在输入的数字是全角数字时,所处理的方法有所区别.现在把两种方法写下来:
VS2003下:       

 1 Code #region Code
 2        //只能输入数字类型
 3        private void textBox2_KeyUp(object sender, KeyEventArgs e)
 4        {
 5            string old = textBox2.Text.Trim();
 6            textBox2.Text = ToDBC(old);
 7           
 8        }
 9        //全角转半角
10        public string ToDBC(string input)
11        {
12            char[] c = input.ToCharArray();
13            for (int i = 0; i < c.Length; i++)
14            {
15                if (c[i] == 12288)
16                {
17                    c[i] = (char)32;
18                    continue;
19                }
20                if (c[i] > 65280 && c[i] < 65375)
21                    c[i] = (char)(c[i] - 65248);
22            }
23            return new string(c);
24        }
25        //键盘按键事件
26        private void textBox2_KeyPress(object sender, KeyPressEventArgs e)
27        {
28            string old = textBox2.Text.Trim();
29            if (!char.IsDigit(e.KeyChar))
30            {
31                e.Handled = true;
32                textBox2.Text = ToDBC(old);
33            }
34            //'\b'是退格键值
35            if (e.KeyChar == '\b' || e.KeyChar == '.')
36            {
37                e.Handled = false;
38            }
39        }
40        #endregion

       VS2005下:          

 1 Code #region Code
 2        //只能输入数字
 3        private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
 4        {
 5           
 6          if (!char.IsDigit(e.KeyChar))
 7            {
 8                e.Handled = true;
 9            }
10            //'\b'是退格键值
11            if (e.KeyChar == '\b') e.Handled = false;
12            switch (e.KeyChar)//处理全角字
13            {
14                case '１':
15                    {
16                        e.KeyChar = '1';
17                        break;
18                    }
19                case '２':
20                    {
21                        e.KeyChar = '2';
22                        break;
23                    }
24                case '３':
25                    {
26                        e.KeyChar = '3';
27                        break;
28                    }
29                case '４':
30                    {
31                        e.KeyChar = '4';
32                        break;
33                    }
34                case '５':
35                    {
36                        e.KeyChar = '5';
37                        break;
38                    }
39                case '６':
40                    {
41                        e.KeyChar = '6';
42                        break;
43                    }
44                case '７':
45                    {
46                        e.KeyChar = '7';
47                        break;
48                    }
49                case '８':
50                    {
51                        e.KeyChar = '8';
52                        break;
53                    }
54                case '９':
55                    {
56                        e.KeyChar = '9';
57                        break;
58                    }
59                case '０':
60                    {
61                        e.KeyChar = '0';
62                        break;
63                    }
64                default: break;
65            }
66
67        }
68        #endregion

          相对来说,2005下,实现起来更容易一些.