VB.NET Convert.ToDateTime方法代码示例

Module ConversionToDateTime
   Public Sub Main()
      Dim dateString As String = Nothing
      
      ' Convert a null string.
      ConvertToDateTime(dateString)
      
      ' Convert an empty string.
      dateString = String.Empty
      ConvertToDateTime(dateString)
      
      ' Convert a non-date string.
      dateString = "not a date"
      ConvertToDateTime(dateString)
      
      ' Try to convert various date strings.
      dateString = "05/01/1996"
      ConvertToDateTime(dateString)
      dateString = "Tue Apr 28, 2009"
      ConvertToDateTime(dateString)
      dateString = "Wed Apr 28, 2009"
      ConvertToDateTime(dateString)
      dateString = "06 July 2008 7:32:47 AM"
      ConvertToDateTime(dateString)
      dateString = "17:32:47.003"
      ConvertToDateTime(dateString)
      ' Convert a string returned by DateTime.ToString("R").
      dateString = "Sat, 10 May 2008 14:32:17 GMT"
      ConvertToDateTime(dateString)
      ' Convert a string returned by DateTime.ToString("o")
      dateString = "2009-05-01T07:54:59.9843750-04:00"
      ConvertToDateTime(dateString)
   End Sub
   
   Private Sub ConvertToDateTime(value As String)
      Dim convertedDate As Date
      Try
         convertedDate = Convert.ToDateTime(value)
         Console.WriteLine("'{0}' converts to {1}.", value, convertedDate)
      Catch e As FormatException
         Console.WriteLine("'{0}' is not in the proper format.", value)
      End Try
   End Sub
End Module

' 导入命名空间
Imports System.Globalization

Module Example
   Public Sub Main( )
      Console.WriteLine("{0,-18}{1,-12}{2}", "Date String", "Culture", "Result")
      Console.WriteLine()

      Dim cultureNames() As String = { "en-US", "ru-RU","ja-JP" }
      Dim dateStrings() As String = { "01/02/09", "2009/02/03",  "01/2009/03", _
                                      "01/02/2009", "21/02/09", "01/22/09",   _
                                      "01/02/23" }
      ' Iterate each culture name in the array.
      For Each cultureName As String In cultureNames
         Dim culture As CultureInfo = New CultureInfo(cultureName)
        
         ' Parse each date using the designated culture.
         For Each dateStr As String In dateStrings
            Dim dateTimeValue As DateTime
            Try
               dateTimeValue = Convert.ToDateTime(dateStr, culture)
                ' Display the date and time in a fixed format.
                Console.WriteLine("{0,-18}{1,-12}{2:yyyy-MMM-dd}", _
                                  dateStr, cultureName, dateTimeValue)
            Catch e As FormatException 
                Console.WriteLine("{0,-18}{1,-12}{2}", _
                                  dateStr, cultureName, e.GetType().Name)
            End Try            
         Next
         Console.WriteLine()
      Next
   End Sub 
End Module

' 导入命名空间
Imports System.Globalization

Module Example
   Public Sub Main()
      Dim cultureNames() As String = { "en-US", "hu-HU", "pt-PT" }
      Dim objects() As Object = { 12, 17.2, False, #1/1/2010#, "today", _
                                  New System.Collections.ArrayList(), "c"c, _
                                  "05/10/2009 6:13:18 PM", "September 8, 1899" }
      
      For Each cultureName As String In cultureNames
         Console.WriteLine("{0} culture:", cultureName)
         Dim provider As New CustomProvider(cultureName)
         For Each obj As Object In objects
            Try
               Dim dateValue As Date = Convert.ToDateTime(obj, provider)      
               Console.WriteLine("{0} --> {1}", obj, _
                                 dateValue.ToString(New CultureInfo(cultureName)))
            Catch e As FormatException
               Console.WriteLine("{0} --> Bad Format", obj)
            Catch e As InvalidCastException
               Console.WriteLine("{0} --> Conversion Not Supported", obj)
            End Try
         Next
         Console.WriteLine()
      Next
   End Sub
End Module

Public Class CustomProvider : Implements IFormatProvider
   Private cultureName As String
   
   Public Sub New(cultureName As String)
      Me.cultureName = cultureName
   End Sub
   
   Public Function GetFormat(formatType As Type) As Object _
          Implements IFormatProvider.GetFormat
      If formatType Is GetType(DateTimeFormatInfo) Then
         Console.Write("(CustomProvider retrieved.) ")
         Return New CultureInfo(cultureName).GetFormat(formatType)
      Else
         Return Nothing
      End If   
   End Function
End Class

Module ConversionToDateTime
   Public Sub Main()
      ' Try converting an integer.
      Dim number As Integer = 16352
      ConvertToDateTime(number)
      
      ' Convert a null.
      Dim obj As Object = Nothing
      ConvertToDateTime(obj)
      
      ' Convert a non-date string.
      Dim nonDateString As String = "monthly"
      ConvertToDateTime(nonDateString)
      
      ' Try to convert various dates.
      Dim dateString As String 
      dateString = "05/01/1996"
      ConvertToDateTime(dateString)
      dateString = "Tue Apr 28, 2009"
      ConvertToDateTime(dateString)
      dateString = "06 July 2008 7:32:47 AM"
      ConvertToDateTime(dateString)
      dateString = "17:32:47.003"
      ConvertToDateTime(dateString)
   End Sub
   
   Private Sub ConvertToDateTime(value As Object)
      Dim convertedDate As Date
      Try
         convertedDate = Convert.ToDateTime(value)
         Console.WriteLine("'{0}' converts to {1}.", value, convertedDate)
      Catch e As FormatException
         Console.WriteLine("'{0}' is not in the proper format.", value)
      Catch e As InvalidCastException
         Console.WriteLine("Conversion of the {0} '{1}' is not supported", _
                           value.GetType().Name, value)
      End Try
   End Sub
End Module