How to check the phone number using Regex

I am trying to check the user input, I want the phone number to be like 000-0000.

But my code here does not work as I want. I input

"123-4444444"

and it also matches.

I am not familiar with Regex, but I need to use it, so can you tell me how to change the pattern?

Regex regex = new Regex(@"\d{3}-\d{4}");
if (!(regex.IsMatch(txtUpdatePhoneNumber.Text)))
{
   MessageBox.Show("Phone number format should be 000-0000", "Error");
}

>Solution :

You have to specify start and beginning

Please check the regex here: https://regex101.com/r/MZ4YPo/1

^: start of string
$: end of string

^\d{3}-\d{4}$

Regex regex = new Regex(@"^\d{3}-\d{4}$");
if (!(regex.IsMatch(txtUpdatePhoneNumber.Text)))
{
    MessageBox.Show("Phone number format should be 000-0000", "Error");
}