例: IsDate function

Dim x As Variant, y As Variant, z As Variant
x = 100                           ' Numeric value
y = CDat(100)                     ' Numeric date value
z = "Nov 2, 1983"                 ' String representing a date
Print IsDate(x)                   ' Output:  False 
Print IsDate(y)                   ' Output:  True
Print IsDate(z)                   ' Output:  True
Print IsDate("100")               ' Output:  False
Print IsDate("Nov 2, 1983")       ' Output:  True