Outlook VBA, display title in MsgBox - vba

Question

I have written the following module to display the Subject of an email that is currently open in Outlook, in a MsgBox.
Outlook 2010. Version 14.0.7140.5002.
I am getting a run-time error '424' Object Required.
With the debugger highlighting:
Set objItem = objApp.ActiveInspector.CurrentItem
Code is below:
Sub ShowTitle()
Dim objMail As Object
Set objItem = objApp.ActiveInspector.CurrentItem
Dim Title As String
Set objMail = objItem.Subject
Title = objItem
MsgBox (Title)
End Sub

Answer 1

Sub ShowTitle()
Dim objMail As Object
Set objItem = objApp.ActiveInspector.CurrentItem
Dim Title As String
Title = objItem.Subject
MsgBox (Title)
End Sub

Answer 2

Try this untested code.
Option Explicit
Sub ShowTitle()
'Dim objApp as Outlook.Application
Dim objItem As Object
Dim Title As String
' If exclusively in Outlook there is no need for objApp
'Set objApp = Outlook.Application
'Set objItem = objApp.ActiveInspector.CurrentItem
' or simpler
'Set objItem = Application.ActiveInspector.CurrentItem
' or simplest
Set objItem = ActiveInspector.CurrentItem
If objItem is mailitem then
Title = objItem.Subject
MsgBox (Title)
End if
'Set objApp = Nothing
Set objItem = Nothing
End Sub

Answer 3

Diane Poremsky over at Slipstick answered this one well in this article. Per her answer, make one module that contains this function:
Function GetCurrentItem() As Object
Dim objApp As Outlook.Application
Set objApp = Application
On Error Resume Next
Select Case TypeName(objApp.ActiveWindow)
Case "Explorer"
Set GetCurrentItem = objApp.ActiveExplorer.Selection.Item(1)
Case "Inspector"
Set GetCurrentItem = objApp.ActiveInspector.CurrentItem
End Select
Set objApp = Nothing
End Function
Then, also per her answer, call that function with this line in your macro:
Set objItem = GetCurrentItem()
So, modifying your code, I made a second macro like this, which works for me:
Sub subjectLine()
Dim Title As String
Set objItem = GetCurrentItem()
Title = objItem.subject
MsgBox (Title)
End Sub
This way, you can run subjectLine() on either a selected email or an open email.