Convert.ToDateTime 方法

參考

定義

命名空間:: System

組件:: System.Runtime.dll

組件:: System.Runtime.Extensions.dll

組件:: mscorlib.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

將指定的值轉換為 DateTime 值。

多載

ToDateTime(Single)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(String)	將指定之日期和時間的字串表示，轉換為相等的日期和時間值。
ToDateTime(UInt16)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(String, IFormatProvider)	使用指定之特定文化特性格式資訊，將指定之數字的字串表示轉換為相等的日期和時間。
ToDateTime(UInt64)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(Object, IFormatProvider)	使用指定之特定文化特性格式資訊，將指定之物件的值轉換為 DateTime 物件。
ToDateTime(SByte)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(UInt32)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(Object)	將指定之物件的值轉換為 DateTime 物件。
ToDateTime(Int16)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(Int32)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(Int64)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(Double)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(Decimal)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(DateTime)	傳回指定的 DateTime 物件；不會執行實際的轉換。
ToDateTime(Char)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(Byte)	呼叫這個方法一律會擲回 InvalidCastException。
ToDateTime(Boolean)	呼叫這個方法一律會擲回 InvalidCastException。

ToDateTime(Single)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(float value);

public static DateTime ToDateTime (float value);

static member ToDateTime : single -> DateTime

Public Shared Function ToDateTime (value As Single) As DateTime

參數

value: Single

要轉換的單精確度浮點數值。

傳回

DateTime

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Single

適用於

ToDateTime(String)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之日期和時間的字串表示，轉換為相等的日期和時間值。

public:
 static DateTime ToDateTime(System::String ^ value);

public static DateTime ToDateTime (string value);

public static DateTime ToDateTime (string? value);

static member ToDateTime : string -> DateTime

Public Shared Function ToDateTime (value As String) As DateTime

參數

value: String

日期和時間的字串表示。

傳回

DateTime

與值相等的value日期和時間，如果 value 為 null，則為 DateTime.MinValue 的日期和時間對等專案。

例外狀況

FormatException

value 不是格式正確的日期和時間字串。

範例

下列範例會 ToDateTime 使用方法，將日期和時間的各種字串表示轉換為 DateTime 值。

using System;

public class ConversionToDateTime
{
   public static void Main()
   {
      string dateString = null;

      // 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);
   }

   private static void ConvertToDateTime(string value)
   {
      DateTime convertedDate;
      try {
         convertedDate = Convert.ToDateTime(value);
         Console.WriteLine("'{0}' converts to {1} {2} time.",
                           value, convertedDate,
                           convertedDate.Kind.ToString());
      }
      catch (FormatException) {
         Console.WriteLine("'{0}' is not in the proper format.", value);
      }
   }
}
// The example displays the following output:
//    '' converts to 1/1/0001 12:00:00 AM Unspecified time.
//    '' is not in the proper format.
//    'not a date' is not in the proper format.
//    '05/01/1996' converts to 5/1/1996 12:00:00 AM Unspecified time.
//    'Tue Apr 28, 2009' converts to 4/28/2009 12:00:00 AM Unspecified time.
//    'Wed Apr 28, 2009' is not in the proper format.
//    '06 July 2008 7:32:47 AM' converts to 7/6/2008 7:32:47 AM Unspecified time.
//    '17:32:47.003' converts to 5/30/2008 5:32:47 PM Unspecified time.
//    'Sat, 10 May 2008 14:32:17 GMT' converts to 5/10/2008 7:32:17 AM Local time.
//    '2009-05-01T07:54:59.9843750-04:00' converts to 5/1/2009 4:54:59 AM Local time.

open System

let convertToDateTime (value: string) =
    try
        let convertedDate = Convert.ToDateTime value
        printfn $"'{value}' converts to {convertedDate} {convertedDate.Kind} time."
    with :?FormatException ->
        printfn $"'{value}' is not in the proper format."

[<EntryPoint>]
let main _ =
    let dateString = null

    // Convert a null string.
    convertToDateTime dateString

    // Convert an empty string.
    let dateString = String.Empty
    convertToDateTime dateString

    // Convert a non-date string.
    let dateString = "not a date"
    convertToDateTime dateString

    // Try to convert various date strings.
    let dateString = "05/01/1996"
    convertToDateTime dateString
    let dateString = "Tue Apr 28, 2009"
    convertToDateTime dateString
    let dateString = "Wed Apr 28, 2009"
    convertToDateTime dateString
    let dateString = "06 July 2008 7:32:47 AM"
    convertToDateTime dateString
    let dateString = "17:32:47.003"
    convertToDateTime dateString
    // Convert a string returned by DateTime.ToString("R").
    let dateString = "Sat, 10 May 2008 14:32:17 GMT"
    convertToDateTime dateString
    // Convert a string returned by DateTime.ToString("o").
    let dateString = "2009-05-01T07:54:59.9843750-04:00"
    convertToDateTime dateString

    0

// The example displays the following output:
//    '' converts to 1/1/0001 12:00:00 AM Unspecified time.
//    '' is not in the proper format.
//    'not a date' is not in the proper format.
//    '05/01/1996' converts to 5/1/1996 12:00:00 AM Unspecified time.
//    'Tue Apr 28, 2009' converts to 4/28/2009 12:00:00 AM Unspecified time.
//    'Wed Apr 28, 2009' is not in the proper format.
//    '06 July 2008 7:32:47 AM' converts to 7/6/2008 7:32:47 AM Unspecified time.
//    '17:32:47.003' converts to 5/30/2008 5:32:47 PM Unspecified time.
//    'Sat, 10 May 2008 14:32:17 GMT' converts to 5/10/2008 7:32:17 AM Local time.
//    '2009-05-01T07:54:59.9843750-04:00' converts to 5/1/2009 4:54:59 AM Local time.

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
' The example displays the following output:
'    '' converts to 1/1/0001 12:00:00 AM.
'    '' is not in the proper format.
'    'not a date' is not in the proper format.
'    '05/01/1996' converts to 5/1/1996 12:00:00 AM.
'    'Tue Apr 28, 2009' converts to 4/28/2009 12:00:00 AM.
'    'Wed Apr 28, 2009' is not in the proper format.
'    '06 July 2008 7:32:47 AM' converts to 7/6/2008 7:32:47 AM.
'    '17:32:47.003' converts to 5/30/2008 5:32:47 PM.
'    'Sat, 10 May 2008 14:32:17 GMT' converts to 5/10/2008 7:32:17 AM.
'    '2009-05-01T07:54:59.9843750-04:00' converts to 5/1/2009 4:54:59 AM.

備註

如果 value 不是 null，則傳回值是使用對象中DateTimeFormatInfo針對目前文化特性初始化的格式資訊叫用方法value的結果DateTime.Parse。自 value 變數必須包含日期和時間的表示法，其格式為主題中所述 DateTimeFormatInfo 的其中一種格式。如果 value 是 null，則方法會傳回 DateTime.MinValue。

這個方法會嘗試完全剖 value 析，並避免擲回 FormatException。它會以目前日期完成遺漏的月份、日和年份資訊。如果 value 只包含日期且沒有時間，則這個方法會假設午夜的時間。中 value 任何前置、內部或尾端空格符都會被忽略。

如果您不想在轉換失敗時處理例外狀況，您可以改為呼叫 DateTime.TryParse 方法。它會傳回值 Boolean ，指出轉換成功或失敗。

另請參閱

適用於

ToDateTime(UInt16)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(System::UInt16 value);

[System.CLSCompliant(false)]
public static DateTime ToDateTime (ushort value);

[<System.CLSCompliant(false)>]
static member ToDateTime : uint16 -> DateTime

Public Shared Function ToDateTime (value As UShort) As DateTime

參數

value: UInt16

要轉換之 16 位元不帶正負號的整數。

傳回

DateTime

不支援此轉換。沒有傳回值。

屬性: CLSCompliantAttribute

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

UInt16

適用於

ToDateTime(String, IFormatProvider)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

使用指定之特定文化特性格式資訊，將指定之數字的字串表示轉換為相等的日期和時間。

public:
 static DateTime ToDateTime(System::String ^ value, IFormatProvider ^ provider);

public static DateTime ToDateTime (string value, IFormatProvider provider);

public static DateTime ToDateTime (string? value, IFormatProvider? provider);

static member ToDateTime : string * IFormatProvider -> DateTime

Public Shared Function ToDateTime (value As String, provider As IFormatProvider) As DateTime

參數

value: String

字串，包含要轉換的日期和時間。

provider: IFormatProvider

物件，提供特定文化特性格式資訊。

傳回

DateTime

與值相等的value日期和時間，如果 value 為 null，則為 DateTime.MinValue 的日期和時間對等專案。

例外狀況

FormatException

value 不是格式正確的日期和時間字串。

範例

下列範例會使用物件，以 ToDateTimeIFormatProvider 方法轉換日期值的字串表示。

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      Console.WriteLine("{0,-18}{1,-12}{2}\n", "Date String", "Culture", "Result");

      string[] cultureNames = { "en-US", "ru-RU","ja-JP" };
      string[] dateStrings = { "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.
      foreach (string cultureName in cultureNames)
      {
         CultureInfo culture = new CultureInfo(cultureName);

         // Parse each date using the designated culture.
         foreach (string dateStr in dateStrings)
         {
            DateTime dateTimeValue;
            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 (FormatException e) {
                Console.WriteLine("{0,-18}{1,-12}{2}",
                                  dateStr, cultureName, e.GetType().Name);
            }
         }
         Console.WriteLine();
      }
   }
}

open System
open System.Globalization

printfn $"""{"Date String",-18}{"Culture",-12}{"Result"}\n"""

let cultureNames = [ "en-US"; "ru-RU"; "ja-JP" ]
let dateStrings =
    [ "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 cultureName in cultureNames do
    let culture = CultureInfo cultureName

    // Parse each date using the designated culture.
    for dateStr in dateStrings do
        try
            let dateTimeValue = Convert.ToDateTime(dateStr, culture)
            // Display the date and time in a fixed format.
            printfn $"""{dateStr,-18}{cultureName,-12}{dateTimeValue.ToString "yyyy-MMM-dd"}"""
        with :? FormatException as e ->
            printfn $"{dateStr,-18}{cultureName,-12}{e.GetType().Name}"
    printfn ""

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 
' The example displays the following output:
'       Date String       Culture     Result
'       
'       01/02/09          en-US       2009-Jan-02
'       2009/02/03        en-US       2009-Feb-03
'       01/2009/03        en-US       2009-Jan-03
'       01/02/2009        en-US       2009-Jan-02
'       21/02/09          en-US       FormatException
'       01/22/09          en-US       2009-Jan-22
'       01/02/23          en-US       2023-Jan-02
'       
'       01/02/09          ru-RU       2009-Feb-01
'       2009/02/03        ru-RU       2009-Feb-03
'       01/2009/03        ru-RU       2009-Jan-03
'       01/02/2009        ru-RU       2009-Feb-01
'       21/02/09          ru-RU       2009-Feb-21
'       01/22/09          ru-RU       FormatException
'       01/02/23          ru-RU       2023-Feb-01
'       
'       01/02/09          ja-JP       2001-Feb-09
'       2009/02/03        ja-JP       2009-Feb-03
'       01/2009/03        ja-JP       2009-Jan-03
'       01/02/2009        ja-JP       2009-Jan-02
'       21/02/09          ja-JP       2021-Feb-09
'       01/22/09          ja-JP       FormatException
'       01/02/23          ja-JP       2001-Feb-23

備註

傳回值是在上value叫用 DateTime.Parse(String, IFormatProvider) 方法的結果。

providerIFormatProvider是取得 DateTimeFormatInfo 對象的實例。物件 DateTimeFormatInfo 提供有關格式 value的文化特性特定資訊。如果為 providernull， DateTimeFormatInfo 則會使用目前文化特性的。

如果您不想在轉換失敗時處理例外狀況，您可以改為呼叫 DateTime.TryParse 方法。它會傳回值 Boolean ，指出轉換成功或失敗。

另請參閱

在 .NET 中剖析日期和時間字串

適用於

ToDateTime(UInt64)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(System::UInt64 value);

[System.CLSCompliant(false)]
public static DateTime ToDateTime (ulong value);

[<System.CLSCompliant(false)>]
static member ToDateTime : uint64 -> DateTime

Public Shared Function ToDateTime (value As ULong) As DateTime

參數

value: UInt64

要轉換之 64 位元不帶正負號的整數。

傳回

DateTime

不支援此轉換。沒有傳回值。

屬性: CLSCompliantAttribute

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

UInt64

適用於

ToDateTime(Object, IFormatProvider)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

使用指定之特定文化特性格式資訊，將指定之物件的值轉換為 DateTime 物件。

public:
 static DateTime ToDateTime(System::Object ^ value, IFormatProvider ^ provider);

public static DateTime ToDateTime (object value, IFormatProvider provider);

public static DateTime ToDateTime (object? value, IFormatProvider? provider);

static member ToDateTime : obj * IFormatProvider -> DateTime

Public Shared Function ToDateTime (value As Object, provider As IFormatProvider) As DateTime

參數

value: Object

實作 IConvertible 介面的物件。

provider: IFormatProvider

物件，提供特定文化特性格式資訊。

傳回

DateTime

與值相等的value日期和時間，如果 value 為 null，則為 DateTime.MinValue 的日期和時間對等專案。

例外狀況

FormatException

value 不是有效的日期和時間值。

InvalidCastException

value 未實作 IConvertible 介面。

-或-

不支援轉換。

範例

下列範例會定義自定義格式提供者 CustomProvider，其 GetFormat 方法會將訊息輸出至已叫用的控制台，然後傳回 DateTimeFormatInfo 文化特性的物件，其名稱會當做參數傳遞至其類別建構函式。每 CustomProvider 一個物件都會用來將物件數位中的項目轉換成日期和時間值。輸出表示 CustomProvider 只有在參數的類型 value 為 String時，才會在轉換中使用物件。

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      string[] cultureNames = { "en-US", "hu-HU", "pt-PT" };
      object[] objects = { 12, 17.2, false, new DateTime(2010, 1, 1), "today",
                           new System.Collections.ArrayList(), 'c',
                           "05/10/2009 6:13:18 PM", "September 8, 1899" };

      foreach (string cultureName in cultureNames)
      {
         Console.WriteLine("{0} culture:", cultureName);
         CustomProvider provider = new CustomProvider(cultureName);
         foreach (object obj in objects)
         {
            try {
               DateTime dateValue = Convert.ToDateTime(obj, provider);
               Console.WriteLine("{0} --> {1}", obj,
                                 dateValue.ToString(new CultureInfo(cultureName)));
            }
            catch (FormatException) {
               Console.WriteLine("{0} --> Bad Format", obj);
            }
            catch (InvalidCastException) {
               Console.WriteLine("{0} --> Conversion Not Supported", obj);
            }
         }
         Console.WriteLine();
      }
   }
}

public class CustomProvider : IFormatProvider
{
   private string cultureName;

   public CustomProvider(string cultureName)
   {
      this.cultureName = cultureName;
   }

   public object GetFormat(Type formatType)
   {
      if (formatType == typeof(DateTimeFormatInfo))
      {
         Console.Write("(CustomProvider retrieved.) ");
         return new CultureInfo(cultureName).GetFormat(formatType);
      }
      else
      {
         return null;
      }
   }
}
// The example displays the following output:
//    en-US culture:
//    12 --> Conversion Not Supported
//    17.2 --> Conversion Not Supported
//    False --> Conversion Not Supported
//    1/1/2010 12:00:00 AM --> 1/1/2010 12:00:00 AM
//    (CustomProvider retrieved.) today --> Bad Format
//    System.Collections.ArrayList --> Conversion Not Supported
//    c --> Conversion Not Supported
//    (CustomProvider retrieved.) 05/10/2009 6:13:18 PM --> 5/10/2009 6:13:18 PM
//    (CustomProvider retrieved.) September 8, 1899 --> 9/8/1899 12:00:00 AM
//
//    hu-HU culture:
//    12 --> Conversion Not Supported
//    17.2 --> Conversion Not Supported
//    False --> Conversion Not Supported
//    1/1/2010 12:00:00 AM --> 2010. 01. 01. 0:00:00
//    (CustomProvider retrieved.) today --> Bad Format
//    System.Collections.ArrayList --> Conversion Not Supported
//    c --> Conversion Not Supported
//    (CustomProvider retrieved.) 05/10/2009 6:13:18 PM --> 2009. 05. 10. 18:13:18
//    (CustomProvider retrieved.) September 8, 1899 --> 1899. 09. 08. 0:00:00
//
//    pt-PT culture:
//    12 --> Conversion Not Supported
//    17.2 --> Conversion Not Supported
//    False --> Conversion Not Supported
//    1/1/2010 12:00:00 AM --> 01-01-2010 0:00:00
//    (CustomProvider retrieved.) today --> Bad Format
//    System.Collections.ArrayList --> Conversion Not Supported
//    c --> Conversion Not Supported
//    (CustomProvider retrieved.) 05/10/2009 6:13:18 PM --> 05-10-2009 18:13:18
//    (CustomProvider retrieved.) September 8, 1899 --> 08-09-1899 0:00:00

open System
open System.Globalization

type CustomProvider(cultureName: string) =
    interface IFormatProvider with
        member _.GetFormat(formatType) =
            if formatType = typeof<DateTimeFormatInfo> then
                printf "(CustomProvider retrieved.) "
                CultureInfo(cultureName).GetFormat formatType
            else
                null

let cultureNames = [ "en-US"; "hu-HU"; "pt-PT" ]
let objects: obj list =
    [ 12; 17.2; false; DateTime(2010, 1, 1); "today"
      System.Collections.ArrayList(); 'c'
      "05/10/2009 6:13:18 PM"; "September 8, 1899" ]

for cultureName in cultureNames do
    printfn $"{cultureName} culture:"
    let provider = CustomProvider cultureName
    for obj in objects do
        try
            let dateValue = Convert.ToDateTime(obj, provider)
            printfn $"{obj} --> {dateValue.ToString(CultureInfo cultureName)}"
        with
        | :? FormatException ->
            printfn $"{obj} --> Bad Format"
        | :? InvalidCastException ->
            printfn $"{obj} --> Conversion Not Supported"
    printfn ""

// The example displays the following output:
//    en-US culture:
//    12 --> Conversion Not Supported
//    17.2 --> Conversion Not Supported
//    False --> Conversion Not Supported
//    1/1/2010 12:00:00 AM --> 1/1/2010 12:00:00 AM
//    (CustomProvider retrieved.) today --> Bad Format
//    System.Collections.ArrayList --> Conversion Not Supported
//    c --> Conversion Not Supported
//    (CustomProvider retrieved.) 05/10/2009 6:13:18 PM --> 5/10/2009 6:13:18 PM
//    (CustomProvider retrieved.) September 8, 1899 --> 9/8/1899 12:00:00 AM
//
//    hu-HU culture:
//    12 --> Conversion Not Supported
//    17.2 --> Conversion Not Supported
//    False --> Conversion Not Supported
//    1/1/2010 12:00:00 AM --> 2010. 01. 01. 0:00:00
//    (CustomProvider retrieved.) today --> Bad Format
//    System.Collections.ArrayList --> Conversion Not Supported
//    c --> Conversion Not Supported
//    (CustomProvider retrieved.) 05/10/2009 6:13:18 PM --> 2009. 05. 10. 18:13:18
//    (CustomProvider retrieved.) September 8, 1899 --> 1899. 09. 08. 0:00:00
//
//    pt-PT culture:
//    12 --> Conversion Not Supported
//    17.2 --> Conversion Not Supported
//    False --> Conversion Not Supported
//    1/1/2010 12:00:00 AM --> 01-01-2010 0:00:00
//    (CustomProvider retrieved.) today --> Bad Format
//    System.Collections.ArrayList --> Conversion Not Supported
//    c --> Conversion Not Supported
//    (CustomProvider retrieved.) 05/10/2009 6:13:18 PM --> 05-10-2009 18:13:18
//    (CustomProvider retrieved.) September 8, 1899 --> 08-09-1899 0:00:00

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
' The example displays the following output:
'    en-US culture:
'    12 --> Conversion Not Supported
'    17.2 --> Conversion Not Supported
'    False --> Conversion Not Supported
'    1/1/2010 12:00:00 AM --> 1/1/2010 12:00:00 AM
'    (CustomProvider retrieved.) today --> Bad Format
'    System.Collections.ArrayList --> Conversion Not Supported
'    c --> Conversion Not Supported
'    (CustomProvider retrieved.) 05/10/2009 6:13:18 PM --> 5/10/2009 6:13:18 PM
'    (CustomProvider retrieved.) September 8, 1899 --> 9/8/1899 12:00:00 AM
'    
'    hu-HU culture:
'    12 --> Conversion Not Supported
'    17.2 --> Conversion Not Supported
'    False --> Conversion Not Supported
'    1/1/2010 12:00:00 AM --> 2010. 01. 01. 0:00:00
'    (CustomProvider retrieved.) today --> Bad Format
'    System.Collections.ArrayList --> Conversion Not Supported
'    c --> Conversion Not Supported
'    (CustomProvider retrieved.) 05/10/2009 6:13:18 PM --> 2009. 05. 10. 18:13:18
'    (CustomProvider retrieved.) September 8, 1899 --> 1899. 09. 08. 0:00:00
'    
'    pt-PT culture:
'    12 --> Conversion Not Supported
'    17.2 --> Conversion Not Supported
'    False --> Conversion Not Supported
'    1/1/2010 12:00:00 AM --> 01-01-2010 0:00:00
'    (CustomProvider retrieved.) today --> Bad Format
'    System.Collections.ArrayList --> Conversion Not Supported
'    c --> Conversion Not Supported
'    (CustomProvider retrieved.) 05/10/2009 6:13:18 PM --> 05-10-2009 18:13:18
'    (CustomProvider retrieved.) September 8, 1899 --> 08-09-1899 0:00:00

備註

傳回值是叫用 IConvertible.ToDateTime 基礎類型 value之方法的結果。

provider 可讓使用者指定有關內容 value的文化特性特定轉換資訊。例如，如果 value 是 String 代表日期的， provider 可能會提供用來表示該日期之表示法的文化特性特定資訊。 provider如果的運行時間型value別是 String，或 value 是實IConvertible.ToDateTime作會使用provider的使用者定義型別，則與的轉換value有關。如果的 value 運行時間類型為 String ，且 provider 為 null，則會 CultureInfo 使用代表目前文化特性的物件。

另請參閱

在 .NET 中剖析日期和時間字串

適用於

ToDateTime(SByte)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(System::SByte value);

[System.CLSCompliant(false)]
public static DateTime ToDateTime (sbyte value);

[<System.CLSCompliant(false)>]
static member ToDateTime : sbyte -> DateTime

Public Shared Function ToDateTime (value As SByte) As DateTime

參數

value: SByte

要轉換的 8 位元帶正負號的整數。

傳回

DateTime

不支援此轉換。沒有傳回值。

屬性: CLSCompliantAttribute

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Byte

適用於

ToDateTime(UInt32)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(System::UInt32 value);

[System.CLSCompliant(false)]
public static DateTime ToDateTime (uint value);

[<System.CLSCompliant(false)>]
static member ToDateTime : uint32 -> DateTime

Public Shared Function ToDateTime (value As UInteger) As DateTime

參數

value: UInt32

要轉換之 32 位元不帶正負號的整數。

傳回

DateTime

不支援此轉換。沒有傳回值。

屬性: CLSCompliantAttribute

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

UInt32

適用於

ToDateTime(Object)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定之物件的值轉換為 DateTime 物件。

public:
 static DateTime ToDateTime(System::Object ^ value);

public static DateTime ToDateTime (object value);

public static DateTime ToDateTime (object? value);

static member ToDateTime : obj -> DateTime

Public Shared Function ToDateTime (value As Object) As DateTime

參數

value: Object

實作 IConvertible 介面的物件，或是 null。

傳回

DateTime

與值相等的value日期和時間，如果 value 為 null，則為 DateTime.MinValue 的日期和時間對等專案。

例外狀況

FormatException

value 不是有效的日期和時間值。

InvalidCastException

value 未實作 IConvertible 介面。

-或-

不支援轉換。

範例

下列範例會使用各種Object變數呼叫 ToDateTime(Object) 方法。

using System;

public class ConversionToDateTime
{
   public static void Main()
   {
      // Try converting an integer.
      int number = 16352;
      ConvertToDateTime(number);

      // Convert a null.
      object obj = null;
      ConvertToDateTime(obj);

      // Convert a non-date string.
      string nonDateString = "monthly";
      ConvertToDateTime(nonDateString);

      // Try to convert various date strings.
      string dateString;
      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);
   }

   private static void ConvertToDateTime(object value)
   {
      DateTime convertedDate;
      try {
         convertedDate = Convert.ToDateTime(value);
         Console.WriteLine("'{0}' converts to {1}.", value, convertedDate);
      }
      catch (FormatException) {
         Console.WriteLine("'{0}' is not in the proper format.", value);
      }
      catch (InvalidCastException) {
         Console.WriteLine("Conversion of the {0} '{1}' is not supported",
                           value.GetType().Name, value);
      }
   }
}
// The example displays the following output:
//       Conversion of the Int32 '16352' is not supported
//       '' converts to 1/1/0001 12:00:00 AM.
//       'monthly' is not in the proper format.
//       '05/01/1996' converts to 5/1/1996 12:00:00 AM.
//       'Tue Apr 28, 2009' converts to 4/28/2009 12:00:00 AM.
//       '06 July 2008 7:32:47 AM' converts to 7/6/2008 7:32:47 AM.
//       '17:32:47.003' converts to 5/28/2008 5:32:47 PM.

open System

let convertToDateTime (value: obj) =
    try
        let convertedDate = Convert.ToDateTime value
        printfn $"'{value}' converts to {convertedDate}."
    with
    | :? FormatException ->
        printfn $"'{value}' is not in the proper format."
    | :? InvalidCastException ->
        printfn $"Conversion of the {value.GetType().Name} '{value}' is not supported"

[<EntryPoint>]
let main _ =
    // Try converting an integer.
    let number = 16352
    convertToDateTime number

    // Convert a null.
    let obj = box null
    convertToDateTime obj

    // Convert a non-date string.
    let nonDateString = "monthly"
    convertToDateTime nonDateString

    // Try to convert various date strings.
    let dateString = "05/01/1996"
    convertToDateTime dateString
    let dateString = "Tue Apr 28, 2009"
    convertToDateTime dateString
    let dateString = "06 July 2008 7:32:47 AM"
    convertToDateTime dateString
    let dateString = "17:32:47.003"
    convertToDateTime dateString

    0

// The example displays the following output:
//       Conversion of the Int32 '16352' is not supported
//       '' converts to 1/1/0001 12:00:00 AM.
//       'monthly' is not in the proper format.
//       '05/01/1996' converts to 5/1/1996 12:00:00 AM.
//       'Tue Apr 28, 2009' converts to 4/28/2009 12:00:00 AM.
//       '06 July 2008 7:32:47 AM' converts to 7/6/2008 7:32:47 AM.
//       '17:32:47.003' converts to 5/28/2008 5:32:47 PM.

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
' The example displays the following output:
'       Conversion of the Int32 '16352' is not supported
'       '' converts to 1/1/0001 12:00:00 AM.
'       'monthly' is not in the proper format.
'       '05/01/1996' converts to 5/1/1996 12:00:00 AM.
'       'Tue Apr 28, 2009' converts to 4/28/2009 12:00:00 AM.
'       '06 July 2008 7:32:47 AM' converts to 7/6/2008 7:32:47 AM.
'       '17:32:47.003' converts to 5/28/2008 5:32:47 PM.

備註

若要讓轉換成功，參數的 value 執行時間類型必須是 DateTime 或 String，或 value 必須是 null。否則，方法會擲回 InvalidCastException。此外，如果 value 是字串，它必須包含目前文化特性中日期和時間值的有效表示法，否則 FormatException 會擲回。

傳回值是叫 IConvertible.ToDateTime 用基礎型 value別之方法的結果。

適用於

ToDateTime(Int16)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(short value);

public static DateTime ToDateTime (short value);

static member ToDateTime : int16 -> DateTime

Public Shared Function ToDateTime (value As Short) As DateTime

參數

value: Int16

要轉換的 16 位元帶正負號的整數。

傳回

DateTime

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Int16

適用於

ToDateTime(Int32)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(int value);

public static DateTime ToDateTime (int value);

static member ToDateTime : int -> DateTime

Public Shared Function ToDateTime (value As Integer) As DateTime

參數

value: Int32

要轉換的 32 位元帶正負號的整數。

傳回

DateTime

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Int32

適用於

ToDateTime(Int64)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(long value);

public static DateTime ToDateTime (long value);

static member ToDateTime : int64 -> DateTime

Public Shared Function ToDateTime (value As Long) As DateTime

參數

value: Int64

要轉換的 64 位元帶正負號的整數。

傳回

DateTime

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Int64

適用於

ToDateTime(Double)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(double value);

public static DateTime ToDateTime (double value);

static member ToDateTime : double -> DateTime

Public Shared Function ToDateTime (value As Double) As DateTime

參數

value: Double

要轉換的雙精確度浮點數值。

傳回

DateTime

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Double

適用於

ToDateTime(Decimal)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(System::Decimal value);

public static DateTime ToDateTime (decimal value);

static member ToDateTime : decimal -> DateTime

Public Shared Function ToDateTime (value As Decimal) As DateTime

參數

value: Decimal

要轉換的數字。

傳回

DateTime

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

適用於

ToDateTime(DateTime)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

傳回指定的 DateTime 物件；不會執行實際的轉換。

public:
 static DateTime ToDateTime(DateTime value);

public static DateTime ToDateTime (DateTime value);

static member ToDateTime : DateTime -> DateTime

Public Shared Function ToDateTime (value As DateTime) As DateTime

參數

value: DateTime

日期和時間值。

傳回

DateTime

value 會原封不動地傳回。

適用於

ToDateTime(Char)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(char value);

public static DateTime ToDateTime (char value);

static member ToDateTime : char -> DateTime

Public Shared Function ToDateTime (value As Char) As DateTime

參數

value: Char

要轉換的 Unicode 字元。

傳回

DateTime

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Char

適用於

ToDateTime(Byte)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(System::Byte value);

public static DateTime ToDateTime (byte value);

static member ToDateTime : byte -> DateTime

Public Shared Function ToDateTime (value As Byte) As DateTime

參數

value: Byte

要轉換之 8 位元不帶正負號的整數。

傳回

DateTime

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Byte

適用於

ToDateTime(Boolean)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫這個方法一律會擲回 InvalidCastException。

public:
 static DateTime ToDateTime(bool value);

public static DateTime ToDateTime (bool value);

static member ToDateTime : bool -> DateTime

Public Shared Function ToDateTime (value As Boolean) As DateTime

參數

value: Boolean

要轉換的布林值。

傳回

DateTime

不支援此轉換。沒有傳回值。

例外狀況

InvalidCastException

不支援此轉換。

另請參閱

Boolean

適用於