例: IsNumeric function

Dim v As Variant
Print IsNumeric(v)               ' Output:  True (v is EMPTY)
v = 12
Print IsNumeric(v)               ' Output:  True
' A string that is not interpretable as a number
v = "Twelve"
Print IsNumeric(v)               ' Output:  False
' A string that is interpretable as a number
v = "12"
Print IsNumeric(v)               ' Output:  True