检查数组是否具有值，如果为空则跳过

问题描述：

因此，我的代码设置为发送一封电子邮件，其中包含符合特定单元格名称（缺少文本）的所有行。如果搜索中没有这些，我希望它绕过并输入无。如果有单元格，它会很好地工作，但是如果没有单元格，我会收到下标超出范围的错误。

So my code is setting up to send an email with all the lines that meet a certain cell name (Missing Text). if there are none of those in the search i want it to bypass and enter in a "None". If there are cells that have it, it works great, but if there is none i get a Subscript out o range error.

Dim MissingText() As Variant
Dim WrongNum() As Variant
Dim BlankText() As Variant
Dim objOutlook As Object
Dim objMsg As Object


Set objOutlook = CreateObject("Outlook.Application")
Erase MissingText, WrongNum, BlankText

Listed = 0
Ending = Cells(Rows.Count, 5).End(xlUp).Row
n = 0
For Listed = 2 To Ending
    If Cells(Listed, 10).Value = "Missing Text" Then
        ReDim Preserve MissingText(n)
        MissingText(n) = Listed
        n = n + 1
    End If

Next Listed
If IsEmpty(MissingText) Then
    MissingTogether = "None"
    GoTo MissingSkip
End If
CountArray = UBound(MissingText, 1) - LBound(MissingText, 1) + 1
CountArray = CountArray - 1
MissingTogether = Join(MissingText, ", ")
MissingSkip:

（续）
在CountArray = UBound（MissingText，1）-LBound（MissingText，1）+ 1是发生错误时。

(continues on ) At the CountArray = UBound(MissingText, 1) - LBound(MissingText, 1) + 1 is when the error occurs. any help would be nice, thank you.

答

正如评论中指出的那样，没有一种本地方法可以确定如果数组在VBA中未初始化。但是，您可以检查其内存占用量，以查看其变量是否包含空指针。请注意， VarPtr 会引发数组的类型不匹配，因此需要先将其包装在 Variant 中：

As pointed out in the comments, there isn't a native way to determine if an array is uninitialized in VBA. However, you can examine its memory footprint to see if its variable contains a null pointer. Note that VarPtr throws a type mismatch for arrays, so it needs to be wrapped in a Variant first:

'In declarations section:
#If VBA7 Then
    Private Declare PtrSafe Sub CopyMemory Lib "kernel32" Alias _
        "RtlMoveMemory" (ByRef Destination As Any, ByRef Source As Any, _
        ByVal length As Long)
#Else
    Private Declare Sub CopyMemory Lib "kernel32" Alias _
        "RtlMoveMemory" (ByRef Destination As Any, ByRef Source As Any, _
        ByVal length As Long)
#End If

Private Const VT_BY_REF As Integer = &H4000&
Private Const DATA_OFFSET As Long = 8

Private Function IsUninitializedArray(SafeArray As Variant) As Boolean
    If Not IsArray(SafeArray) Then
        Exit Function
    End If

    Dim vtype As Integer
    'First 2 bytes are the VARENUM.
    CopyMemory vtype, SafeArray, LenB(vtype)
#If VBA7 Then
    Dim lp As LongPtr
#Else
    Dim lp As Long
#End If
    'Get the data pointer.
    CopyMemory lp, ByVal VarPtr(SafeArray) + DATA_OFFSET, LenB(lp)
    'Make sure the VARENUM is a pointer.
    If (vtype And VT_BY_REF) <> 0 Then
        'Dereference it for the actual data address.
        CopyMemory lp, ByVal lp, LenB(lp)
        IsUninitializedArray = lp <> 0
    End If
End Function

用法示例：

Public Sub Example()
    Dim Test() As String
    MsgBox IsUninitializedArray(Test) 'False

    Test = Split(vbNullString)
    MsgBox IsUninitializedArray(Test) 'True

    Erase Test
    MsgBox IsUninitializedArray(Test) 'False
End Sub

检查数组是否具有值，如果为空则跳过

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