Doubts about using Contains with Regex in C#

Question

I would like to use in a code in C# the method Contains , but instead of spending one string literal, ie a specific word, pass a pattern or a regular expression as parameter. For example: Instead of going through:

bool nomeDaVariavel.Contains("#NUSAPRO");

go through something like:

String verifica = @"^#/[A-Z]{1,7}";
//Padrão que captura qualquer String 
//que comece com o "#", 
//seguido de um a sete caracteres de A a Z em caixa grande

bool nomeDaVariavel.Contains(verifica);

Sure the syntax is wrong, but it’s just to get an idea of what I intend.

If you could help, I’d be grateful.

Answer 1

You need to use the class Regex to apply regular expression to the strings you want to compare. The code below shows an example of how this can be done.

String verifica = @"^#[A-Z]{1,7}";
Regex verificaRegex = new Regex(verifica);
var negativos = new string[] { "ABCDEFG", "#aBCDEFG", "# ABCDEFg", "#aBCDEFG", "#1BCDEFG" };
var positivos = new string[] { "#ABCDEFG", "#ABCDEFG1", "#ABCDEFGHIJKL", "#ABCDEFG abc" };

Console.WriteLine("Negativos:");
foreach (var neg in negativos)
{
    Console.WriteLine(verificaRegex.IsMatch(neg));
}

Console.WriteLine("Positivos:");
foreach (var pos in positivos)
{
    Console.WriteLine(verificaRegex.IsMatch(pos));
}