How can we make textbox only contain numbers, Chinese characters, and letters?

In programming, textbox is often used to accept only numbers (or others, such as Chinese characters, letters, and so on ), at this time, we may need to re-encapsulate a Textbox (other methods can also be used). We often see someone asking this question. Today, I took some time to encapsulate it. Now I share it with you, I hope to provide some help to you. If there is anything wrong, please make an axe. In addition, if you need to reprint it, please indicate the source:
Half smoke Ajie. Http://blog.csdn.net/gisfarmer/ thanks.
Only code with numbers (INT type) can be entered. (copy the Code directly)

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. // When the focus changes, you can choose one as needed.
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 ("the input content is invalid! "," Input prompt ");
21. This. Focus ();
22. }
23. Else
24. {
25. This. backcolor = color. Beige;
26. }
27. }
28. }
30. // When the content changes
31. Public void textchage (Object sender, system. eventargs E)
32. {
33. Selectpos = This. selectionstart;
34. If (this. Text! = "")
35. {
36. // Zhengzhou expression is used here
    
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. // Convert the fullwidth to halfwidth. You can also select this function.
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. }

The following code can only be used to enter floating-point numbers (similar to other Chinese characters, letters, and so on)

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. // When the focus changes
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 ("the input content is invalid! "," Input prompt ");
21. This. Focus ();
22. }
23. Else
24. {
25. This. backcolor = color. Beige;
26. }
27. }
28. }
30. // When the content changes
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. // Convert the fullwidth to halfwidth
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. }