TimeSpan.FromHours(Double) TimeSpan.FromHours(Double) TimeSpan.FromHours(Double) TimeSpan.FromHours(Double) Method

定义

返回表示指定小时数的 TimeSpan,其中对小时数的指定精确到最接近的毫秒。Returns a TimeSpan that represents a specified number of hours, where the specification is accurate to the nearest millisecond.

public:
 static TimeSpan FromHours(double value);
public static TimeSpan FromHours (double value);
static member FromHours : double -> TimeSpan
Public Shared Function FromHours (value As Double) As TimeSpan

参数

value
Double Double Double Double

精确到最接近的毫秒的小时数。A number of hours accurate to the nearest millisecond.

返回

表示 value 的对象。An object that represents value.

异常

value 小于 MinValue 或大于 MaxValuevalue is less than MinValue or greater than MaxValue.

-or- valuePositiveInfinityvalue is PositiveInfinity.

-or- valueNegativeInfinityvalue is NegativeInfinity.

示例

下面的示例FromHours使用方法TimeSpan创建几个对象。The following example creates several TimeSpan objects using the FromHours method.

// Example of the TimeSpan::FromHours( double ) method.
using namespace System;
void GenTimeSpanFromHours( double hours )
{
   
   // Create a TimeSpan object and TimeSpan string from 
   // a number of hours.
   TimeSpan interval = TimeSpan::FromHours( hours );
   String^ timeInterval = interval.ToString();
   
   // Pad the end of the TimeSpan string with spaces if it 
   // does not contain milliseconds.
   int pIndex = timeInterval->IndexOf( ':' );
   pIndex = timeInterval->IndexOf( '.', pIndex );
   if ( pIndex < 0 )
      timeInterval = String::Concat( timeInterval, "        " );

   Console::WriteLine( "{0,21}{1,26}", hours, timeInterval );
}

int main()
{
   Console::WriteLine( "This example of TimeSpan::FromHours( double )\n"
   "generates the following output.\n" );
   Console::WriteLine( "{0,21}{1,18}", "FromHours", "TimeSpan" );
   Console::WriteLine( "{0,21}{1,18}", "---------", "--------" );
   GenTimeSpanFromHours( 0.0000002 );
   GenTimeSpanFromHours( 0.0000003 );
   GenTimeSpanFromHours( 0.0012345 );
   GenTimeSpanFromHours( 12.3456789 );
   GenTimeSpanFromHours( 123456.7898765 );
   GenTimeSpanFromHours( 0.0002777 );
   GenTimeSpanFromHours( 0.0166666 );
   GenTimeSpanFromHours( 1 );
   GenTimeSpanFromHours( 24 );
   GenTimeSpanFromHours( 500.3389445 );
}

/*
This example of TimeSpan::FromHours( double )
generates the following output.

            FromHours          TimeSpan
            ---------          --------
                2E-07          00:00:00.0010000
                3E-07          00:00:00.0010000
            0.0012345          00:00:04.4440000
           12.3456789          12:20:44.4440000
       123456.7898765     5144.00:47:23.5550000
            0.0002777          00:00:01
            0.0166666          00:01:00
                    1          01:00:00
                   24        1.00:00:00
          500.3389445       20.20:20:20.2000000
*/
// Example of the TimeSpan.FromHours( double ) method.
using System;

class FromHoursDemo
{
    static void GenTimeSpanFromHours( double hours )
    {
        // Create a TimeSpan object and TimeSpan string from 
        // a number of hours.
        TimeSpan    interval = TimeSpan.FromHours( hours );
        string      timeInterval = interval.ToString( );

        // Pad the end of the TimeSpan string with spaces if it 
        // does not contain milliseconds.
        int pIndex = timeInterval.IndexOf( ':' );
        pIndex = timeInterval.IndexOf( '.', pIndex );
        if( pIndex < 0 )   timeInterval += "        ";

        Console.WriteLine( "{0,21}{1,26}", hours, timeInterval );
    } 

    static void Main( )
    {
        Console.WriteLine(
            "This example of TimeSpan.FromHours( double )\n" +
            "generates the following output.\n" );
        Console.WriteLine( "{0,21}{1,18}",
            "FromHours", "TimeSpan" );
        Console.WriteLine( "{0,21}{1,18}", 
            "---------", "--------" );

        GenTimeSpanFromHours( 0.0000002 );
        GenTimeSpanFromHours( 0.0000003 );
        GenTimeSpanFromHours( 0.0012345 );
        GenTimeSpanFromHours( 12.3456789 );
        GenTimeSpanFromHours( 123456.7898765 );
        GenTimeSpanFromHours( 0.0002777 );
        GenTimeSpanFromHours( 0.0166666 );
        GenTimeSpanFromHours( 1 );
        GenTimeSpanFromHours( 24 );
        GenTimeSpanFromHours( 500.3389445 );
    } 
} 

/*
This example of TimeSpan.FromHours( double )
generates the following output.

            FromHours          TimeSpan
            ---------          --------
                2E-07          00:00:00.0010000
                3E-07          00:00:00.0010000
            0.0012345          00:00:04.4440000
           12.3456789          12:20:44.4440000
       123456.7898765     5144.00:47:23.5550000
            0.0002777          00:00:01
            0.0166666          00:01:00
                    1          01:00:00
                   24        1.00:00:00
          500.3389445       20.20:20:20.2000000
*/ 
' Example of the TimeSpan.FromHours( Double ) method.
Module FromHoursDemo

    Sub GenTimeSpanFromHours( hours As Double )

        ' Create a TimeSpan object and TimeSpan string from 
        ' a number of hours.
        Dim interval As TimeSpan = _
            TimeSpan.FromHours( hours )
        Dim timeInterval As String = interval.ToString( )

        ' Pad the end of the TimeSpan string with spaces if it 
        ' does not contain milliseconds.
        Dim pIndex As Integer = timeInterval.IndexOf( ":"c )
        pIndex = timeInterval.IndexOf( "."c, pIndex )
        If pIndex < 0 Then  timeInterval &= "        "

        Console.WriteLine( "{0,21}{1,26}", hours, timeInterval )
    End Sub 

    Sub Main( )

        Console.WriteLine( "This example of " & _
            "TimeSpan.FromHours( Double )" & _
            vbCrLf & "generates the following output." & vbCrLf )
        Console.WriteLine( "{0,21}{1,18}", _
            "FromHours", "TimeSpan" )    
        Console.WriteLine( "{0,21}{1,18}", _
            "---------", "--------" )    

        GenTimeSpanFromHours( 0.0000002 )
        GenTimeSpanFromHours( 0.0000003 )
        GenTimeSpanFromHours( 0.0012345 )
        GenTimeSpanFromHours( 12.3456789 )
        GenTimeSpanFromHours( 123456.7898765 )
        GenTimeSpanFromHours( 0.0002777 )
        GenTimeSpanFromHours( 0.0166666 )
        GenTimeSpanFromHours( 1 )
        GenTimeSpanFromHours( 24 )
        GenTimeSpanFromHours( 500.3389445 )
    End Sub 
End Module 

' This example of TimeSpan.FromHours( Double )
' generates the following output.
' 
'             FromHours          TimeSpan
'             ---------          --------
'                 2E-07          00:00:00.0010000
'                 3E-07          00:00:00.0010000
'             0.0012345          00:00:04.4440000
'            12.3456789          12:20:44.4440000
'        123456.7898765     5144.00:47:23.5550000
'             0.0002777          00:00:01
'             0.0166666          00:01:00
'                     1          01:00:00
'                    24        1.00:00:00
'           500.3389445       20.20:20:20.2000000

注解

参数转换为毫秒,转换为计时周期,并使用该计时周期数来初始化新TimeSpan的。 valueThe value parameter is converted to milliseconds, which is converted to ticks, and that number of ticks is used to initialize the new TimeSpan. 因此, value将只视为精确到最接近的毫秒。Therefore, value will only be considered accurate to the nearest millisecond. Double请注意,由于数据类型的精度丢失,此转换可以OverflowException为接近但仍MinValue处于或MaxValue范围内的值生成。Note that, because of the loss of precision of the Double data type, this conversion can generate an OverflowException for values that are near to but still in the range of either MinValue or MaxValue. 例如, OverflowException在以下情况下,这会导致尝试TimeSpan实例化对象。For example, this causes an OverflowException in the following attempt to instantiate a TimeSpan object.

// The following throws an OverflowException at runtime
TimeSpan maxSpan = TimeSpan.FromHours(TimeSpan.MaxValue.TotalHours);
' The following throws an OverflowException at runtime
Dim maxSpan As TimeSpan = TimeSpan.FromHours(TimeSpan.MaxValue.TotalHours)

适用于

另请参阅