How to determine that a null character does not give an error in a sentence

Question

** I wanted to check a sentence whether contains one null character between two words. I am new. So, there is not much of code samples for This problem. **

I used String.IsNullOrEmpty to determine the emptiness of the string. However, I did wrong.

Can you help me about that?

**Edit: I'm sorry for My mistake. This question needs an example. For example; I Write to the textbox "It is good" It determines null characters between "It" and "is" AND "is" and "good". So, it gives an error message. However, İf I Write one single character, it does not give me error message.

PS: This error message means a label. If it contains a null character, Red label shows itself. Else, Green label shows itself.**

Edit 2

Public Static bool IsAllLetters(string s)

{ foreach (char c in s) { if (!char.IsLetter(c) return false; return true; }

I determine whether the string contains Letter or not. If it contains a number character, it gives error.

Anyway, that explains why I used IsAllLetter function.

then I used This code samples.

Bool exp = IsAllLetters(explanation_text.Text);

İf (exp == false){ // wrong data } 

Else { // correct data }

So, Which Code should I change? Or What Code should I add?

Possible duplicate of [C# - What does "\0" equate to?](https://stackoverflow.com/questions/2292850/c-sharp-what-does-0-equate-to) — mjwills, Jul 10 '17 at 11:46
Post your code and explain what the problem is. Post a *reproducible* example. There is no such thing as a null character in a string. There is a character named `NUL` but that's no different than *any* other character — Panagiotis Kanavos, Jul 10 '17 at 11:48
By "Null" do you really mean whitespace? (space, tab, newline, etc.) — Colin Mackay, Jul 10 '17 at 11:53
Don't use `NULL` character if you just mean a space. What is the error and what is the code that causes it? A label has no problems with spaces — Tim Schmelter, Jul 10 '17 at 11:56

score 0 · Answer 1 · answered Jul 10 '17 at 12:33

Your code formatting is a bit rough, but it looks like your foreach returns prematurely when the string has Length greater than 1

foreach (char c in s)
   { if (!char.IsLetter(c) return false; return true; }

The code above only ever checks the first character of a string. Instead, you want IsAllLetters to only return true if all characters have been scanned.

public static bool IsAllLetters(string s)
{
    foreach (char c in s)
        if (!char.IsLetter(c)) return false;

    return true;
}

I do not want to get the error message when I left a Black between two words in the sentence. — raskolnikov, Jul 10 '17 at 12:38

How to determine that a null character does not give an error in a sentence

1 Answers1