TryParse in one line: accepted challenge? [duplicate]

Question

Just a challenge I guess, but I hope to use TryParse in just one line :) My code:

DateTime tempDate;
user.DataNascita = DateTime.TryParse(txtDataDiNascita.Text, out tempDate) ? tempDate : (DateTime?)null;

user.DataNascita is DateTime?, and I want to return the data if TryParse is correct, null otherwise. But I need the out one (so, new line). Can't I have all in one line?

Just curious...

Answer 1

I'm usually using this extension method in LINQ queries:

public static DateTime? TryGetDate(this string dateString, string format = null)
{
    DateTime dt;
    bool success = format == null ? DateTime.TryParse(dateString, out dt) : DateTime.TryParseExact(dateString, format, null, DateTimeStyles.None, out dt);
    return success ? dt : (DateTime?)null;
}

You use it in this way:

user.DataNascita = txtDataDiNascita.Text.TryGetDate();

Here's another overload with multiple formats and an IFormatProvider(different cultures):

public static DateTime? TryGetDate(this string dateString, IFormatProvider provider, params string[] formats)
{
    DateTime dt;
    var success = DateTime.TryParseExact(dateString, formats, provider, DateTimeStyles.None, out dt);
    return success ? dt : (DateTime?)null;
}

Answer 2

You'd need a helper method, basically. For example:

public static DateTime? TryParseDateTime(string text)
{
    DateTime validDate;
    return DateTime.TryParse(text, out validDate) ? validDate : (DateTime?) null;
}

Then you can just use:

user.DataNascita = ParseHelpers.TryParseDateTime(txtDataDiNascita.Text);

You'd probably want overloads corresponding with the overloads of DateTime.TryParse and DateTime.TryParseExact, too. I wouldn't personally make this an extension method as per Tim's answer, but that's a matter of personal preference.