如何在VB代码中编写特殊字符

Question

I have a Sql statament using special character (ex: ('), (/), (&)) and I don't know how to write them in my VB.NET code. Please help me. Thanks.

Answer 1

Find out the Unicode code point for the character (from http://www.unicode.org ) and then use ChrW to convert from the code point to the character. (To put this in another string, use concatenation. I'm somewhat surprised that VB doesn't have an escape sequence, but there we go.)

For example, for the Euro sign (U+20AC) you'd write:

Dim euro as Char = ChrW(&H20AC)

The advantage of this over putting the character directly into source code is that your source code stays "just pure ASCII" - which means you won't have any strange issues with any other program trying to read it, diff it, etc. The disadvantage is that it's harder to see the symbol in the code, of course.

Answer 2

The most common way seems to be to append a character of the form Chr(34)... 34 represents a double quote character. The character codes can be found from the windows program "charmap"... just windows/Run... and type charmap

Answer 3

The ' character can be doubled up to allow it into a string eg

lSQLSTatement = "Select * from temp where name = 'fred''s'" 

Will search for all records where name = fred's

Answer 4

If you are passing strings to be processed as SQL statement try doubling the characters for example.

"SELECT * FROM MyRecords WHERE MyRecords.MyKeyField = ""With a "" Quote"" "

The '' double works with the other special characters as well.

Answer 5

Three points:

1) The example characters you've given are not special characters. They're directly available on your keyboard. Just press the corresponding key.

2) To type characters that don't have a corresponding key on the keyboard, use this:

Alt + (the ASCII code number of the special character)

For example, to type ¿, press Alt and key in 168 , which is the ASCII code for that special character.

You can use this method to type a special character in practically any program not just a VB.Net text editor.

3) What you probably looking for is what is called 'escaping' characters in a string. In your SQL query string, just place a \\ before each of those characters. That should do.

Answer 6

Chr() is probably the most popular. ChrW() can be used if you want to generate unicode characters The ControlChars class contains some special and 'invisible' characters, plus the quote - for example, ControlChars.Quote