动态数组在VB语言中常能起到出奇制胜的作用。但数组有没有被重新定义或释放,用“is empty”,“is null”,“=" "”等方法都不起作用。所以判断时一般采用侦别错误消息(ON ERROR )的方法。下面给出一个非错误侦别的代码,判断动态字符串数组的分配情况:
Private Sub Command1_Click()Dim a() As String, i As Long
MsgBox hasredim(a), 64, "Has a() been redimed?" ''''未初始化
ReDim a(20)
For i = 1 To 20a(i) = chr(i+64)
Next
MsgBox hasredim(a), 64, "Has a() been redimed?" ''''初始化后
Erase a ''''释放空间后MsgBox hasredim(a), 64, "Has a() been redimed?"
End Sub
Function hasredim(ByRef x() As String) As Boolean ''''定义布尔函数Dim temp As Stringtemp = Join(x, ",") hasredim = LenB(temp) > 0 ''''空数组长度为零End Function
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