Date

Converting (Parsing) a String to a Date

If you know the format of the string you are converting (parsing) you should use DateTime.ParseExact

Dim dateString As String = "12.07.2003"
Dim dateFormat As String = "dd.MM.yyyy"
Dim dateValue As Date

dateValue = DateTime.ParseExact(dateString, dateFormat, Globalization.CultureInfo.InvariantCulture)

If you are not certain for the format of the string, you can use DateTime.TryParseExact and test the result to see if parsed or not:

Dim dateString As String = "23-09-2013"
Dim dateFormat As String = "dd-MM-yyyy"
Dim dateValue As Date

If DateTime.TryParseExact(dateString, dateFormat, Globalization.CultureInfo.InvariantCulture, DateTimeStyles.None, dateValue) Then
    'the parse worked and the dateValue variable now holds the datetime that was parsed as it is passing in ByRef
Else
    'the parse failed
End If

Converting a Date To A String

Simply use the .ToString overload of a DateTime object to get the format you require:

Dim dateValue As DateTime = New DateTime(2001, 03, 06)
Dim dateString As String = dateValue.ToString("yyyy-MM-dd") '2001-03-06