String was not recognized as a valid DateTime " format dd/MM/yyyy"

I am trying to convert my string formatted value to date type with format dd/MM/yyyy.

this.Text="22/11/2009";

DateTime date = DateTime.Parse(this.Text);

What is the problem ? It has a second override which asks for IFormatProvider. What is this? Do I need to pass this also? If Yes how to use it for this case?

Edit

What are the differences between Parse and ParseExact?

Edit 2

Both answers of Slaks and Sam are working for me, currently user is giving the input but this will be assured by me that they are valid by using maskTextbox.

Which answer is better considering all aspects like type saftey, performance or something you feel like

Solution 1:

Use DateTime.ParseExact.

this.Text="22/11/2009";

DateTime date = DateTime.ParseExact(this.Text, "dd/MM/yyyy", null);

Solution 2:

You need to call ParseExact, which parses a date that exactly matches a format that you supply.

For example:

DateTime date = DateTime.ParseExact(this.Text, "dd/MM/yyyy", CultureInfo.InvariantCulture);

The IFormatProvider parameter specifies the culture to use to parse the date.
Unless your string comes from the user, you should pass CultureInfo.InvariantCulture.
If the string does come from the user, you should pass CultureInfo.CurrentCulture, which will use the settings that the user specified in Regional Options in Control Panel.

Solution 3:

Parsing a string representation of a DateTime is a tricky thing because different cultures have different date formats. .Net is aware of these date formats and pulls them from your current culture (System.Threading.Thread.CurrentThread.CurrentCulture.DateTimeFormat) when you call DateTime.Parse(this.Text);

For example, the string "22/11/2009" does not match the ShortDatePattern for the United States (en-US) but it does match for France (fr-FR).

Now, you can either call DateTime.ParseExact and pass in the exact format string that you're expecting, or you can pass in an appropriate culture to DateTime.Parse to parse the date.

For example, this will parse your date correctly:

DateTime.Parse( "22/11/2009", CultureInfo.CreateSpecificCulture("fr-FR") );

Of course, you shouldn't just randomly pick France, but something appropriate to your needs.

What you need to figure out is what System.Threading.Thread.CurrentThread.CurrentCulture is set to, and if/why it differs from what you expect.