DateTime.MinValue DateTime.MinValue DateTime.MinValue DateTime.MinValue Field

定义

表示 DateTime 的最小可能值。Represents the smallest possible value of DateTime. 此字段为只读。This field is read-only.

public: static initonly DateTime MinValue;
public static readonly DateTime MinValue;
 staticval mutable MinValue : DateTime
Public Shared ReadOnly MinValue As DateTime 

字段值

示例

下面的示例实例化DateTime对象表示通过其构造函数Int64值,该值表示计时周期数。The following example instantiates a DateTime object by passing its constructor an Int64 value that represents a number of ticks. 调用构造函数之前, 示例可确保此值是大于或等于DateTime.MinValue.Ticks且小于或等于DateTime.MaxValue.TicksBefore invoking the constructor, the example ensures that this value is greater than or equal to DateTime.MinValue.Ticks and less than or equal to DateTime.MaxValue.Ticks. 如果不是,引发ArgumentOutOfRangeExceptionIf not, it throws an ArgumentOutOfRangeException.

// Attempt to assign an out-of-range value to a DateTime constructor.
long numberOfTicks = Int64.MaxValue;
DateTime validDate;

// Validate the value.
if (numberOfTicks >= DateTime.MinValue.Ticks &&
    numberOfTicks <= DateTime.MaxValue.Ticks) 
   validDate = new DateTime(numberOfTicks);
else if (numberOfTicks < DateTime.MinValue.Ticks) 
   Console.WriteLine("{0:N0} is less than {1:N0} ticks.", 
                     numberOfTicks, 
                     DateTime.MinValue.Ticks);      
else
   Console.WriteLine("{0:N0} is greater than {1:N0} ticks.", 
                     numberOfTicks,
                     DateTime.MaxValue.Ticks);
// The example displays the following output:
//   9,223,372,036,854,775,807 is greater than 3,155,378,975,999,999,999 ticks.
' Attempt to assign an out-of-range value to a DateTime constructor.
Dim numberOfTicks As Long = Int64.MaxValue
Dim validDate As Date

' Validate the value.
If numberOfTicks >= Date.MinValue.Ticks And _
   numberOfTicks <= Date.MaxValue.Ticks Then
   validDate = New Date(numberOfTicks)
ElseIf numberOfTicks < Date.MinValue.Ticks Then
   Console.WriteLine("{0:N0} is less than {1:N0} ticks.", 
                     numberOfTicks, 
                     DateTime.MinValue.Ticks)      
Else                                                   
   Console.WriteLine("{0:N0} is greater than {1:N0} ticks.", 
                     numberOfTicks, 
                     DateTime.MaxValue.Ticks)     
End If
' The example displays the following output:
'   9,223,372,036,854,775,807 is greater than 3,155,378,975,999,999,999 ticks.      

注解

此常量的值为等效于 00:00:00.0000000 UTC,1 月 1 日 0001,公历日历中。The value of this constant is equivalent to 00:00:00.0000000 UTC, January 1, 0001, in the Gregorian calendar.

MinValue 定义的日期和时间分配到未初始化DateTime变量。MinValue defines the date and time that is assigned to an uninitialized DateTime variable. 下面的示例阐释了这一点。The following example illustrates this.

// Define an uninitialized date.
DateTime date1 = new DateTime();
Console.Write(date1);
if (date1.Equals(DateTime.MinValue))
   Console.WriteLine("  (Equals Date.MinValue)");
// The example displays the following output:
//    1/1/0001 12:00:00 AM  (Equals Date.MinValue)
' Define an uninitialized date.
Dim date1 As Date
Console.Write(date1)
If date1.Equals(Date.MinValue) Then _
   Console.WriteLine("  (Equals Date.MinValue)")
' The example displays the following output:
'    1/1/0001 12:00:00 AM  (Equals Date.MinValue)

MinValueMaxValue属性可用于确保将它传递到前一个值位于受支持的范围内DateTime构造函数。The MinValue and MaxValue properties can be used to ensure that a value lies within the supported range before passing it to a DateTime constructor. 示例部分中的代码说明了这种用法。The code in the Example section illustrates this usage.

适用于