基本功能

检索系统日期时间

VBA 支持 3 个内置函数，用于从系统时钟中检索日期和/或时间。

Sub DateTimeExample()

    ' -----------------------------------------------------
    ' Note : EU system with default date format DD/MM/YYYY
    ' -----------------------------------------------------
    
    Debug.Print Now   ' prints 28/07/2016 10:16:01 (output below assumes this date and time)
    Debug.Print Date  ' prints 28/07/2016
    Debug.Print Time  ' prints 10:16:01
    
    ' Apply a custom format to the current date or time
    Debug.Print Format$(Now, "dd mmmm yyyy hh:nn")  ' prints 28 July 2016 10:16
    Debug.Print Format$(Date, "yyyy-mm-dd")         ' prints 2016-07-28
    Debug.Print Format$(Time, "hh") & " hour " & _
                Format$(Time, "nn") & " min " & _
                Format$(Time, "ss") & " sec "       ' prints 10 hour 16 min 01 sec
    
End Sub

定时器功能

Timer 函数返回一个 Single，表示自午夜以来经过的秒数。精度是百分之一秒。

Sub TimerExample()

    Debug.Print Time    ' prints 10:36:31  (time at execution)
    Debug.Print Timer   ' prints 38191,13  (seconds since midnight)

End Sub

由于 Now 和 Time 功能仅精确到秒，Timer 提供了一种提高时间测量精度的便捷方法：

Sub GetBenchmark()
       
    Dim StartTime  As Single
    StartTime = Timer       'Store the current Time
    
    Dim i As Long
    Dim temp As String
    For i = 1 To 1000000    'See how long it takes Left$ to execute 1,000,000 times
        temp = Left$("Text", 2)
    Next i
    
    Dim Elapsed As Single
    Elapsed = Timer - StartTime
    Debug.Print "Code completed in " & CInt(Elapsed * 1000) & " ms"

End Sub

则 IsDate()

IsDate() 测试表达式是否是有效日期。返回 Boolean。

Sub IsDateExamples()

    Dim anything As Variant
       
    anything = "September 11, 2001"

    Debug.Print IsDate(anything)    'Prints True
            
    anything = #9/11/2001#

    Debug.Print IsDate(anything)    'Prints True
   
    anything = "just a string"

    Debug.Print IsDate(anything)    'Prints False

    anything = vbNull
    
    Debug.Print IsDate(anything)    'Prints False
    
End Sub