我得到的對象未設置爲對象錯誤的實例。我已經列出了所有消息應該顯示的列表視圖。我使用lumisoft sample code我移植到VB.NETVB.net:對象未設置爲對象的實例
Private Sub FillMessagesList()
Me.Cursor = Cursors.WaitCursor
Try
Dim m_pPop3 As POP3_Client = Nothing
For Each message As POP3_ClientMessage In m_pPop3.Messages
Dim mime As Mail_Message = Mail_Message.ParseFromByte(message.HeaderToByte())
Dim item As New ListViewItem()
If mime.From IsNot Nothing Then
item.Text = mime.From.ToString()
Else
item.Text = "<none>"
End If
If String.IsNullOrEmpty(mime.Subject) Then
item.SubItems.Add("<none>")
Else
item.SubItems.Add(mime.Subject)
End If
item.SubItems.Add(mime.[Date].ToString())
item.SubItems.Add(CDec(message.Size/CDec(1000)).ToString("f2") & " kb")
item.Tag = message
ListView1.Items.Add(item)
Next
Catch x As Exception
MessageBox.Show(Me, "Errorssssss: " + x.Message)
End Try
Me.Cursor = Cursors.[Default]
End Sub
逐步通過它,看看哪一行是拋出異常。你可能會從那裏弄清楚它。 – 2011-01-27 20:43:21
嗯,我試過了,我認爲Dim item As New ListViewItem()............如果發生錯誤 – 2011-01-27 20:45:05
該行不會創建NullReferenceException。這種異常類型通常是一個「點」異常,其中您要放的點是空的。下面的答案似乎是正確的。 – 2011-01-27 20:52:52