The text text box in the WinForm form only allows the data letters to control how regular expression

Register the keypress event for this textbox.

new ;

Then implement the method.

private void txtuserid_keypress(object sender, keypresseventargs e)

if (('z' &&'a') |== '\b')= false;

true;In fact, if you only enter letters, you won't need regular expressions at all. Use the above method to do the trick.

Determine the ASCII code of the character you entered in the keypress event of the textbox.

if（>=97 &&=122 ||=65 &&=90）= false;

true;

Convert the strings in the text to an array of characters, and iterate through the entire array to determine whether it is a letter or not.

Let's say the text box is txtuser

regex re = new regex("^[a-za-z]*$", ;

string str=;

if (Correct.) else

Error, mismatch.

The correct way to do this is to add a beginning and end mark.

string putter = "^[^',;=?$\x22]+$";This means that from the beginning to the end there are 1 n non-special characters.

**As follows: regex reg = new regex(@"^\d(?:d)?$");

if (!else

[^%',;=?$\x22]+

This is a match of 1 n %',;=?$\", enter f'At this point, f is passed', because f is the correct character, matching f returns true

The correct way to do this is to add a beginning and end mark.

string putter = "^[^',;=?$\x22]+$";This means that from the beginning to the end there are 1 n non-special characters.

private void textbox1_keypress(object sender, keypresseventargs e)else

This is the realization that you can only enter the numbers 0-9, as well as the letters a-z, a-z, if you need to add something else.

Then use the regular put.

C Usage: TextBox Text Box ID: txt Value Chinese Character: U4E00- U9FA5]+$

using ;Referencing namespaces.

string reg value= @u4e00- u9fa5]+$ can only be entered in Chinese.

if (!reg_value))

If you want to determine if you want to enter something else, you just need to change the regular.

If you can enter it, just enter it directly.

using ;

public static bool isemail(string value)

|(a-z0-9][\w\.-a-z0-9]\.

a-z][a-z\.]a-z]$");

You can call this method, I hope it will help you, and if you have any questions, please ask or hi

header file using ;

bool istrue = ,@"p (write your regular expression in quotation marks).");

if (!istrue)

"What to verify","Regular expressions")

Add a keypress event to the form's text box (e.g. textbox1 keypress below).

private void textbox1_keypress(object sender, keypresseventargs e)

After the test, you can only enter Chinese characters, if you enter something else, there is no response.

If you still have any questions about the above, you can hi me.

var str="***"The text var patt=@ in the text box"^[\u4e00-\u9fa5]+$"This is the pattern to match.

var r=new regex(patt);

var pasflag=;true identifies matching the prescribed format, false does not.

Add the onblur() event of textbox to the backend pageload, and then write a judgment function in js.

If you want to verify whether Chinese is included after input, please use the regular expression on the first floor.

If you want to prohibit Chinese input methods when typing, please change the imemode property of the control to disabled (or change it in **) in the designer

Method 2 will cause the focus to be unable to switch through the keyboard shortcut when this control opens other input methods, and the floating box of the input method will also be hidden.

Only numbers and English:

Convert the input to ASCII code If it is greater than 128, it is a Chinese character, and the regular expression should not be able to judge the Chinese character.

Do you want the textbox to not be able to input Chinese characters or numbers? Regular expressions just limit the type of input.

You can write a method to limit it, it's not very troublesome, look up more libraries, pay more attention to properties and methods, it's good for learning, read more, and have an impression when you use it.

In regex, the matching character is: [u4e00- u9fa5].

The engineering documents are sent to you, I hope they will be helpful to you.

Remove tags with regular expressions.