方法一：Error方法
就是採用通用的錯誤捕獲功能
On Error Goto 行號 '遇到錯誤，轉到行號處處理
On Error Resume Next '忽略錯誤，繼續執行
On Error Goto 0 '強制取消錯誤捕獲功能
Function IsNotEmpty(ByVal sArray As Variant) As Boolean '判斷數組是否爲空
Dim i As Long
IsNotEmpty = True
On Error GoTo lerr:
i = UBound(b)
Exit Function
lerr:
IsNotEmpty = False
End Function
方法二：CopyMemory方法
VB的數組都是安全數組，通過訪問一個結構來確定 數組內容保存位置，上標下標和維數
安全數組結構的地址可以用
Private Declare Function VarPtrArray Lib "msvbvm60.dll" Alias "VarPtr" (ByRef Ptr() As Any) As Long
Private Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" _
(ByRef Destination As Any, ByRef Source As Any, ByVal Length As Long)
安全數組的頭兩位就保存着維數信息
Option Explicit
Private Declare Function VarPtrArray Lib "msvbvm60.dll" Alias "VarPtr" (ByRef Ptr() As Any) As Long
Private Declare Sub CopyMemory Lib "kernel32.dll" Alias "RtlMoveMemory" (ByRef Destination As Any, ByRef Source As Any, ByVal Length As Long)
Private Sub Form_Load()
Dim MyArr() As Long
Dim pMyarr As Long
Dim nDims As Integer
'從數據指針得到SafeArray結構的指針
CopyMemory pMyarr, ByVal VarPtrArray(MyArr), 4
If pMyarr = 0 Then
MsgBox "這個數組是空數組"
'再從這個指針所指地址的頭兩個字節取出cDims
CopyMemory nDims, ByVal pMyarr, 2
MsgBox "這個數組有" & nDims & "維"
End If
End Sub
方法三：使用api函數safearraygetdim()的返回值，返回值值<=0,說明數組元素個數爲0或者數組還沒有初始化.
SafeArrayGetDim用來判斷一個數組的維數，該函數在MSDN中定義爲：
UINT SafeArrayGetDim(
SAFEARRAY FAR* psa
轉換維VB中的語法格式爲：
Public Declare Function SafeArrayGetDim Lib "oleaut32.dll" (ByRef saArray() As Any) As Long
如果數組已經初始化，則返回非0，否則返回0。
'API判斷數組爲空或沒有初始化
Sub diag()
Dim msg As String
Dim arr1() As String, arr2() As String, arr3() As Date, arr4() As Date, arr5() As Range, arr6() As Range
msg = "arr1 " & IIf(SafeArrayGetDim(arr1) > 0, "數組不爲空!", "數組爲空!")
arr2 = Split("一、二、三、四、五、六", "、")
msg = msg & vbCrLf & "arr2 " & IIf(SafeArrayGetDim(arr2) > 0, "數組不爲空!", "數組爲空!")
msg = msg & vbCrLf & "arr3 " & IIf(SafeArrayGetDim(arr3) > 0, "數組不爲空!", "數組爲空!")
ReDim arr4(1 To 100)
msg = msg & vbCrLf & "arr4 " & IIf(SafeArrayGetDim(arr4) > 0, "數組不爲空!", "數組爲空!")
ReDim arr6(1 To 256, 1 To 65536)
msg = msg & vbCrLf & "arr5 " & IIf(SafeArrayGetDim(arr5) > 0, "數組不爲空!", "數組爲空!")
msg = msg & vbCrLf & "arr6 " & IIf(SafeArrayGetDim(arr6) > 0, "數組不爲空!", "數組爲空!")
MsgBox msg
End Sub
方法四：使用cstr(Join(list[, delimiter]))函數的返回值是否不等於""
將delimiter參數設置爲""
例如:if (cstr(join(arr,""))) = "" then msgbox "arr 數組爲空或者尚未初始化"