How to shorten string to specific length according to textBox1.Length c#

Question

I need to know how to shorten a string to a certain length, I tried string.Trim() but it is not working. Sorry I'm still a beginner.

Thanks

Edit

I'm trying to cut off padding from decrypted text. For example: A user inputs text, the user encrypts and decrypts text. On the decrypted text there is padding left...

Edit 2

I'm using PaddingMode.PKCS7

A lot of `string` methods might help you. Can you please show your string first and the result string as you want? — Soner Gönül, Apr 02 '15 at 11:00
@DilanV Perhaps the problem is in the encryption/decryption instead of being in the padding :) — xanatos, Apr 02 '15 at 12:18
@DilanV Compare your code with http://stackoverflow.com/a/4925859/613130 — xanatos, Apr 02 '15 at 12:48
@DilanV Perhaps you are setting the PaddingMode only on encryptor only on decrypt, or you have different PaddingMode. The PaddingMode, if present, must be the same on both encrypt and decrypt. — xanatos, Apr 03 '15 at 06:40

score 1 · Accepted Answer · answered Apr 02 '15 at 12:52

In general the problem is probably in the encryption/decryption. You are encrypting/decrypting with PaddingMode.Zeros, that pads with \0... Now, you could

string decrypted = ...
decrypted = decrypted.TrimEnd('\0');

but it would be at least partially wrong.

Change both the encryption and the decryption adding:

algo.Padding = PaddingMode.ISO10126

(where algo is the object you use to encrypt/decrypt, like a RijndaelManaged)

score 0 · Answer 2 · answered Apr 02 '15 at 10:45

0

You can use Substring() method of string class like

textBox1.Text.Substring(0, 7);

answered Apr 02 '15 at 10:45

Rahul

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score -1 · Answer 3 · answered Apr 02 '15 at 10:46

Strings are immutable, that means you cannot modify them. You have to re-assign the return value of the string methods to the string variable. You can use String.Substring:

int length = textBox1.Text.Length;
longString = longString.Substring(0, Math.Min(length, longString.Length));

How to shorten string to specific length according to textBox1.Length c#

3 Answers3