Visual C# programming help?

I created a program that takes a phone number and divides it into three parts (AAA) EEE - NNNN. I need it to give a default area code if the user doesnt enter one. Heres what I have so far.





private void btnValidate_Click(object sender, EventArgs e)


{


//declare phone number


string phoneDigits;


string exchange;


string areaCode;


string number;





phoneDigits = txtNumber.Text;





areaCode = phoneDigits.Substring(0,3);


exchange = phoneDigits.Substring(3,3);


number = phoneDigits.Substring(6,4);


txtA.Text = areaCode;


txtE.Text = exchange;


txtN.Text = number;


}


}


The program should also accept AAA.EEE.NNNN as a valid phone number, too. (That is, the separation character between the area code, exchange, and number can be either a hyphen or a period.) If the number entered does not fit this format, you should issue an error message that asks them to re-enter the phone number.

Visual C# programming help?
I'd study regular expressions to help you determine the validity of the strings. There are many online tools that help you evaluate strings with this standard approach.





Query: "Regular Expression Telephone Number"