This is probably a basic question but I am very new to C# so bare with me. I am trying to make it so when a text box (labeled LastNameTextBox) is not filled in and a user clicks the Print button a message will pop up that says "Please enter a last name." I also have to do this with a first and last name and have already gotten this to work with a phone number in a Mased Text Box. This is my code thus far in this section:


string s = String.Empty;
Boolean pn = PhoneNumberMaskedTextBox.MaskFull;
Boolean ln = LastNameTextBox.
Boolean fn = FirstNameTextBox.

if (pn == false)
{
s = s + "Please enter a phone number.";
MessageBox.Show(s, "FUN Error Message", MessageBoxButtons.OK);
}

if (ln == false)
{
s = s + "Please enter a last name.";
MessageBox.Show(s, "FUN Error Message", MessageBoxButtons.OK);
}

if ((ln == false) && (fn == false))
{
s = s + "Please enter a full name.";
MessageBox.Show(s, "FUN Error Message", MessageBoxButtons.OK);
}


My problem is that I can't seem to figure out what comes after the period in LastNameTextBox. (same issue with FirstNameTextBox.) What do I need to put after those periods?