“编译错误：未定义用户定义的类型”

Question

运行程序以通过Outlook发送电子邮件时，出现标题中提到的错误。谁能帮忙吗？突出显示第二行-
 enter image description here将 olApp设置为Outlook.Application

代码：

Sub send_mail(address As String, subject As String, mail_body As String)
'

'
Dim **olApp As Outlook.Application**
Set olApp = CreateObject("Outlook.Application")
Dim olMail As Outlook.mailitem
Set olMail = olApp.CreateItem(olMailItem)

olMail.To = address
olMail.subject = "Maintenance Activity at: " & subject
olMail.Body = "Equipment to be maintained: " & mail_body
olMail.CC = Sheets("Expiry").Range("M8").Value
olMail.send

End Sub

Sub mass_mail()
n = Now()
MsgBox "date: " & n
If MsgBox("Are You Sure? ", vbYesNo, " Warning! ") = vbYes Then
Dim row_number As Integer
row_number = 4

Do
DoEvents

row_number = row_number + 1
If Range("D" & row_number).Value >= n And Range("D" & row_number).Value < (n + 30) Then
Call send_mail(Sheet1.Range("L" & row_number), Sheet1.Range("C" & row_number), Sheet1.Range("D" & row_number))
MsgBox "Date: " & Range("D" & row_number).Value
End If
Loop Until row_number = 10
MsgBox ("Messages(s) Sent!")
End If
End Sub

Answer 1

早期绑定的库参考：

您需要在项目引用中添加对Outlook库的引用。

在可视化基本编辑器中，您需要转到“工具”>“引用”，然后向下滚动以找到适合您Office版本的Microsoft Outlook对象库

对我来说，这是16.0版

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后期绑定：

或者，您可以使用以下方法将库调用转换为后期绑定，它不需要添加库引用，并且在将应用程序分发给可能具有不同Office版本的其他用户时更加安全。

  _dbContext.SalesOrderLookup()
            .Where(x => (x.Status.EqualsTrim("Open") == parameters.Open)
                        || (x.Status.EqualsTrim("Closed") == parameters.Closed)
                        || (x.Status.EqualsTrim("Cancel") == parameters.Canceled)).ToList();

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早期绑定和后期绑定的信息：

1. Early and Late Binding (Visual Basic)