ms-access - How do I add Error message if my me.combo box is not selected for the following code?

Question

Add Error message if my me.combo box is not selected for the following code?

Private Sub Command1_Click()
Dim Recipient As String
Dim RecipientCC As String
Recipient = Me.Combo10.Column(2)
RecipientCC = Me.Combo10.Column(3)
Dim DateText As String
DateText = Format(Date - IIf(Weekday(Date) < 3, 1 + Weekday(Date), 1), "MM-DD-YYYY")

DoCmd.TransferText acExportDelim, , "watchdog", "G:\Common\Auto Finance\WatchDog\watchdog_" & [DateText] & ".csv", True

    'send email
    Dim olApp As Outlook.Application
    Dim olMail As Outlook.MailItem

     'get application
    On Error Resume Next
    Set olApp = GetObject(, "Outlook.Application")
    If olApp Is Nothing Then Set olApp = New Outlook.Application
    On Error GoTo 0

    Set olMail = olApp.CreateItem(olMailItem)
    With olMail
        .Subject = "Indirect Auto Watchdog File"
        .Recipients.Add [Recipient]
        .CC = [RecipientCC]
        .Attachments.Add "G:\Common\Auto Finance\WatchDog\watchdog_" & [DateText] & ".csv"
        .Body = ""
        .Display 'This will display the message for you to check and send yourself
         '.Send ' This will send the message straight away
    End With

MsgBox "Email Sent"
End Sub

Answer 1

为什么不添加 if...else 循环？

Private Sub Command1_Click()

if me.combobox.value<>"" then
   'do your task here
else
   'display error message
end if
End Sub