Convert.ToDateTime 方法

定義

命名空間:: System

組件:: netstandard.dll, System.Runtime.dll

組件:: System.Runtime.Extensions.dll

組件:: mscorlib.dll

組件:: netstandard.dll

組件:: mscorlib.dll, System.Runtime.Extensions.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。

將指定的值轉換為某個 DateTime 值。

多載

名稱	Description
ToDateTime(Single)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(String)	將指定的字串表示日期與時間轉換為等效的日期與時間值。
ToDateTime(UInt16)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(String, IFormatProvider)	將指定的數字字串表示轉換為相當的日期與時間，並使用指定的文化特定格式資訊。
ToDateTime(UInt64)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(Object, IFormatProvider)	利用指定的文化特有格式資訊，將指定物件的值轉換為物件 DateTime 。
ToDateTime(SByte)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(UInt32)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(Object)	將指定物件的值轉換成物件。DateTime
ToDateTime(Double)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(Int32)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(Int16)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(Int64)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(Decimal)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(DateTime)	回傳指定的 DateTime 物件;不會實際進行轉換。
ToDateTime(Char)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(Byte)	呼叫此方法總是拋 InvalidCastException出。
ToDateTime(Boolean)	呼叫此方法總是拋 InvalidCastException出。

ToDateTime(Single)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫此方法總是拋 InvalidCastException出。

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

要轉換的單精度浮點數。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

Single

適用於

ToDateTime(String)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定的字串表示日期與時間轉換為等效的日期與時間值。

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

日期與時間的串表示法。

傳回

DateTime

若為 value，則為的日期與時間等價值，或 DateTime.MinValue 的日期與時間等價value值。null

例外狀況

FormatException

value 不是正確格式化的日期和時間字串。

範例

以下範例使用此 ToDateTime 方法將各種日期與時間的字串表示轉換為 DateTime 數值。

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

若 value 不是 null，則回傳值是使用 DateTime.Parse 該方法 value 在物件中初始化為當前文化的格式資訊 DateTimeFormatInfo 所產生的結果。論 value 證必須包含以主題 DateTimeFormatInfo 中描述的格式之一表示日期與時間。若 value ， null則方法返回 DateTime.MinValue。

此方法嘗試完整解析 value 並避免拋 FormatException出。它會補足缺失的月份、日期和年份資訊，並附上當前日期。若 value 只包含日期且無時間，此方法假設時間為午夜。任何前置、內側或後方的空白字 value 元都被忽略。

如果你不想在轉換失敗時處理例外，可以直接呼叫該 DateTime.TryParse 方法。它會回傳 Boolean 一個值，表示轉換是否成功。

另請參閱

CurrentCulture
解析 .NET

適用於

ToDateTime(UInt16)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

呼叫此方法總是拋 InvalidCastException出。

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

16位元無符號整數要轉換。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

屬性: CLSCompliantAttribute

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

UInt16

適用於

ToDateTime(String, IFormatProvider)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定的數字字串表示轉換為相當的日期與時間，並使用指定的文化特定格式資訊。

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，提供特定文化特性的格式資訊。

傳回

DateTime

若為 value，則為的日期與時間等價值，或 DateTime.MinValue 的日期與時間等價value值。null

例外狀況

FormatException

value 不是正確格式化的日期和時間字串。

範例

以下範例使用物件將日期值的字串表示轉換 ToDateTime 成該方法 IFormatProvider 。

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

回傳值是呼叫該方法後DateTime.Parse(String, IFormatProvider)value的結果。

provider 是一個 IFormatProvider 獲得物件 DateTimeFormatInfo 的實例。該 DateTimeFormatInfo 物件提供關於格式 value的文化特定資訊。若 provider ，nullDateTimeFormatInfo則為當前文化。

如果你不想在轉換失敗時處理例外，可以直接呼叫該 DateTime.TryParse 方法。它會回傳 Boolean 一個值，表示轉換是否成功。

另請參閱

解析 .NET

適用於

ToDateTime(UInt64)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

呼叫此方法總是拋 InvalidCastException出。

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

64 位元無符號整數用於轉換。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

屬性: CLSCompliantAttribute

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

UInt64

適用於

ToDateTime(Object, IFormatProvider)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

利用指定的文化特有格式資訊，將指定物件的值轉換為物件 DateTime 。

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

一個實作介面的 IConvertible 物件。

provider: IFormatProvider

物件，提供特定文化特性的格式資訊。

傳回

DateTime

若為 value，則為的日期與時間等價值，或 DateTime.MinValue 的日期與時間等價value值。null

例外狀況

FormatException

value 不是一個有效的日期和時間值。

InvalidCastException

value 未實作該 IConvertible 介面。

-或-

轉換不支援。

範例

以下範例定義了一個自訂格式提供者，其CustomProviderGetFormat方法會向主控台輸出訊息，告知已被調用，然後回傳DateTimeFormatInfo該文化中名稱作為參數傳入類別建構器的物件。這些 CustomProvider 物件用來將物件陣列中的元素轉換為日期與時間值。輸出表示 CustomProvider 該物件僅在參數類型 value 為 String時才用於轉換。

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

回傳值是調 IConvertible.ToDateTime 用底層類型 value方法的結果。

provider 使用者能指定關於內容 value的文化專屬轉換資訊。例如，若 value 代表日期的 a String ， provider 則可提供該日期所用符號的文化特定資訊。 provider若執行時value型別為 value，或String為使用者定義型別且實value作使用，IConvertible.ToDateTime則參與的轉換provider。若執行時型value態為Stringprovider且為，nullCultureInfo則使用代表當前文化的物件。

另請參閱

解析 .NET

適用於

ToDateTime(SByte)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

呼叫此方法總是拋 InvalidCastException出。

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

8位元有符號整數用於轉換。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

屬性: CLSCompliantAttribute

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

Byte

適用於

ToDateTime(UInt32)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

重要

此 API 不符合 CLS 規範。

呼叫此方法總是拋 InvalidCastException出。

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

32位元無符號整數要轉換。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

屬性: CLSCompliantAttribute

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

UInt32

適用於

ToDateTime(Object)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

將指定物件的值轉換成物件。DateTime

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

一個實作介面的 IConvertible 物件，或 null。

傳回

DateTime

若為 value，則為的日期與時間等價值，或 DateTime.MinValue 的日期與時間等價value值。null

例外狀況

FormatException

value 不是一個有效的日期和時間值。

InvalidCastException

value 未實作該 IConvertible 介面。

-或-

轉換不支援。

範例

以下範例以多種ToDateTime(Object)變數呼叫該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

若要成功轉換，參數的 value 執行時類型必須是 a DateTime 或 Stringa，或 value 是 null。否則，該方法會拋出一個 InvalidCastException。此外，若 value 為字串，必須包含當前文化中有效表示的日期與時間值，否則會拋出 a FormatException 。

回傳值是調 IConvertible.ToDateTime 用底層類型 value方法的結果。

適用於

ToDateTime(Double)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫此方法總是拋 InvalidCastException出。

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。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

Double

適用於

ToDateTime(Int32)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫此方法總是拋 InvalidCastException出。

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位帶正負號整數。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

Int32

適用於

ToDateTime(Int16)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫此方法總是拋 InvalidCastException出。

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位帶正負號整數。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

Int16

適用於

ToDateTime(Int64)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫此方法總是拋 InvalidCastException出。

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位帶正負號整數。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

Int64

適用於

ToDateTime(Decimal)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫此方法總是拋 InvalidCastException出。

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

要轉換的數位。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

例外狀況

InvalidCastException

此轉換不被支援。

適用於

ToDateTime(DateTime)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

回傳指定的 DateTime 物件;不會實際進行轉換。

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 未改變地返回。

適用於

ToDateTime(Char)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫此方法總是拋 InvalidCastException出。

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

此轉換不被支援。沒有任何價值回傳。

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

Char

適用於

ToDateTime(Byte)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫此方法總是拋 InvalidCastException出。

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

要轉換的是 8 位元無符號整數。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

Byte

適用於

ToDateTime(Boolean)

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

來源:: Convert.cs

呼叫此方法總是拋 InvalidCastException出。

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

轉換時的布林值。

傳回

DateTime

此轉換不被支援。沒有任何價值回傳。

例外狀況

InvalidCastException

此轉換不被支援。

另請參閱

Boolean

適用於

意見反應

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