Checking conditions on letters?

Question

C++ / C#

string bukv = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            if (textBox.Text != bukv)
            {
            }
            else
            {
                MessageBox.Show("Ошибка: Регистр букв должен быть большим и на Английском языке.");
            }

There is such a code. But it is not working, I need to do it, so that there would be a spell check, if such a letter does not occur, then an error.

Answer 1

Read about regular expressions

Answer 2

Well, you can raise the register yourself - you won’t break and you probably shouldn’t throw an error about it. And the letters themselves are checked by regular expressions - and quite simple ones. If you are really bad with them - https://regex101.com you can practice here.

Answer 3

bool state = false;
foreach(ch in textBox.Text)
{
      if(!char.IsUpper(ch))
      state = true;
}
if(state)
   MessageBox.Show("Ошибка: Регистр букв должен быть большим и на Английском языке.");