Outlook VBA如何将MailItem保存在自定义对象属性中

Question

我正在尝试将 MailItem 对象存储在我的自定义对象的属性中以便稍后调用，但我收到以下错误：

Run-time error '91': Object variable or With block variable not set

这是我的 Class1：

Private vprop1 As String
Private vprop2 As String
Private vprop3 As MailItem

Property Get prop1() As String
    prop1 = vprop1
End Property

Property Let prop1(aValue As String)
    vprop1 = aValue
End Property

Property Get prop2() As String
    prop2 = vprop2
End Property

Property Let prop2(aValue As String)
    vprop2 = aValue
End Property

Property Get prop3() As MailItem
    prop3 = vprop3
End Property

Property Let prop3(aValue As MailItem)
    vprop3 = aValue
End Property

这是我的测试。错误是引用第三个属性赋值：var.prop3 = ...

Public Sub test()
    Set objsourcefolder = Application.Session.GetDefaultFolder(olFolderInbox)

    Dim var As Class1
    Set var = New Class1

    var.prop1 = "\folder\sub\12345"
    var.prop2 = "Email subject regarding 12345"
    var.prop3 = objsourcefolder.Items.Item(objsourcefolder.Items.count)

    Debug.Print var.prop1
    Debug.Print var.prop2
    Debug.Print var.prop3
    Debug.Print var.prop3.Subject
End Sub

非常感谢任何帮助！

Answer 1

由于MailItem 是object，您必须通过Set 关键字设置任何引用它的变量并将Property Let（与非object 类型属性相关联）更改为Property Set （关联到object 类型属性）

最后你不能使用Debug.Print var.prop3，因为你的Class1类型没有任何默认属性作为它的prop3object成员

以上所有结果：

---

类代码

Private vprop1 As String '<--| vprop1 is declared as of 'String' type, i.e. NOT as an 'object'
Private vprop2 As String '<--| vprop2 is declared as of 'String' type, i.e. NOT as an 'object'
Private vprop3 As MailItem '<--| vprop3 is declared as of 'MailItem' type, i.e. as an 'object'

Property Get prop1() As String
    prop1 = vprop1
End Property

Property Let prop1(aValue As String)
    vprop1 = aValue
End Property

Property Get prop2() As String
    prop2 = vprop2
End Property

Property Let prop2(aValue As String)
    vprop2 = aValue
End Property

Property Get prop3() As MailItem
    Set prop3 = vprop3 '<--| use 'Se't keyword
End Property

Property Set prop3(aValue As MailItem) '<--| use 'Property Set' instead of 'Property Let'
    Set vprop3 = aValue '<--| use 'Set' keyword
End Property

---

测试子代码

Public Sub test()
    Dim objsourcefolder As Folder
    Set objsourcefolder = Application.Session.GetDefaultFolder(olFolderInbox)

    Dim var As Class1
    Set var = New Class1

    var.prop1 = "\folder\sub\12345"
    var.prop2 = "Email subject regarding 12345"
    Set var.prop3 = objsourcefolder.Items.Item(objsourcefolder.Items.Count)

    Debug.Print var.prop1
    Debug.Print var.prop2
'    Debug.Print var.prop3 '<--| this would result in an 438 error
    Debug.Print var.prop3.Subject
End Sub