如何讓TextBox只能輸入數字、漢字、字母？

在編程的過程中我們可能經常會用到TextBox只接受數字輸入（或者其他，比如：漢字，字母，等等），這個時候我們可能需要重新封裝一個TextBox（其他方法當然也可以），經常看到有人問這個問題，今天抽了一點時間將此封裝做了一下，現在共用大家，希望能給大家帶來一定的協助，如有不妥敬請斧正，另外：如需轉載請註明出處：
半支煙阿傑。http://blog.csdn.net/gisfarmer/ 謝謝。
只能輸入數字（int型）的代碼（直接複製就ＯＫ了）

1. public class IntTextBox : System.Windows.Forms.TextBox
2.     {
3.         private int selectPos = 0;
4.         public IntTextBox()
5.             : base()
6.         {
7.             this.BackColor = Color.Beige;
8.             this.TextChanged += new EventHandler(this.TextChage);
9.             this.Leave += new EventHandler(this.FocusLeave);
10.         }
11.         //焦點發生改變時，此處你可以根據自己需要自己選擇
12.         public void FocusLeave(object sender, System.EventArgs e)
13.         {
14.             if (this.Text != "")
15.             {
16.                 this.Text = ToDBC(this.Text);
17.                 if (!(new Regex(@"^-?/d+$")).IsMatch(this.Text))
18.                 {
19.                     this.BackColor = Color.OrangeRed;
20.                     MessageBox.Show("輸入內容不合法！", "輸入提示");
21.                     this.Focus();
22.                 }
23.                 else
24.                 {
25.                     this.BackColor = Color.Beige;
26.                 }
27.             }
28.         }
30.         //內容發生改變時
31.         public void TextChage(object sender, System.EventArgs e)
32.         {
33.             selectPos = this.SelectionStart;
34.             if (this.Text != "")
35.             {   
36.                 //此處採用鄭州運算式
    
37.                 if (!(new Regex(@"^-?/d+$")).IsMatch(this.Text))
38.                 {
39.                     this.BackColor = Color.OrangeRed;
40.                     this.SelectionStart = selectPos;
41.                 }
42.                 else
43.                 {
44.                     this.BackColor = Color.Beige;
45.                     this.SelectionStart = selectPos;
46.                 }
47.             }
48.             else
49.             {
50.                 this.BackColor = Color.Beige;
51.             }
52.         }
54.         //全形轉換成半形，此功能也可以選擇
55.         public string ToDBC(string input)
56.         {
57.             char[] c = input.ToCharArray();
58.             for (int i = 0; i < c.Length; i++)
59.             {
60.                 if (c[i] == 12288)
61.                 {
62.                     c[i] = (char)32;
63.                     continue;
64.                 }
65.                 if (c[i] > 65280 && c[i] < 65375)
66.                     c[i] = (char)(c[i] - 65248);
67.             }
68.             return new string(c);
69.         }
70.     }

下面代碼是只能輸入浮點數（至於其他的比如漢字、字母等等原理一樣）

1.     public class FloatTextBox : System.Windows.Forms.TextBox
2.     {
3.         private int selectPos = 0;
4.         public FloatTextBox()
5.             : base()
6.         {
7.             this.BackColor = Color.Beige;
8.             this.TextChanged += new EventHandler(this.TextChage);
9.             this.Leave += new EventHandler(this.FocusLeave);
10.         }
11.         //焦點發生改變時
12.         public void FocusLeave(object sender, System.EventArgs e)
13.         {
14.             if (this.Text != "")
15.             {
16.                 this.Text = ToDBC(this.Text);
17.                 if (!(new Regex(@"^/d+(/./d+)?$")).IsMatch(this.Text))
18.                 {
19.                     this.BackColor = Color.OrangeRed;
20.                     MessageBox.Show("輸入內容不合法！", "輸入提示");
21.                     this.Focus();
22.                 }
23.                 else
24.                 {
25.                     this.BackColor = Color.Beige;
26.                 }
27.             }
28.         }
30.         //內容發生改變時
31.         public void TextChage(object sender, System.EventArgs e)
32.         {
33.             selectPos = this.SelectionStart;
34.             if (this.Text != "")
35.             {
36.                 if (!(new Regex(@"^/d+(/./d+)?$")).IsMatch(this.Text))
37.                 {
38.                     this.BackColor = Color.OrangeRed;
39.                     this.SelectionStart = selectPos;
40.                 }
41.                 else
42.                 {
43.                     this.BackColor = Color.Beige;
44.                     this.SelectionStart = selectPos;
45.                 }
46.             }
47.             else
48.             {
49.                 this.BackColor = Color.Beige;
50.             }
51.         }
53.         //全形轉換成半形
54.         public string ToDBC(string input)
55.         {
56.             char[] c = input.ToCharArray();
57.             for (int i = 0; i < c.Length; i++)
58.             {
59.                 if (c[i] == 12288)
60.                 {
61.                     c[i] = (char)32;
62.                     continue;
63.                 }
64.                 if (c[i] > 65280 && c[i] < 65375)
65.                     c[i] = (char)(c[i] - 65248);
66.             }
67.             return new string(c);
68.         }
69.     }