如何在ToString（）中转义点

Question

I have a string phone number that I want to format:

string PhoneNumber { get; set; }

[..]
long fonenum;

if (Int64.TryParse(PhoneNumber, out fonenum)) {
    if (PhoneNumber.Length <= 9) {
        return fonenum.ToString("#0000.0000");
    }
    else if (PhoneNumber.Length == 10) {
        return fonenum.ToString("(00) 0000.0000");
    }
    [..]
}

but the "." is being confused with decimal place and outputs a floated number, that in my current culture will add the decimal place as ",":

3333-4444 -> 3333,4444

How I force to show the dot as phone number separator?

Sure I could just add Culture "US" and get what I want, but I don't even think it's the right way.

Answer 1

Escape it by prepending a backslash:

fonenum.ToString("#0000\\.0000")

The backslash above is doubled because I am using a non- verbatim string literal.

Answer 2

用单引号将其转义：

fonenum.ToString("#0000'.'0000")

Answer 3

I tested a bit more and have found another too:

fonenum.ToString(@"#0000\\.0000")

Related to Jon answer ("@" escapes the "\\").