爲什麼我的活動運行兩次？

Question

我有一個按鈕

<asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" UseSubmitBehavior="False" /> 

和我的事件是

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click 
     Dim con As New SqlConnection(ConfigurationManager.ConnectionStrings("Document_RecordConnectionString1").ToString()) 
     con.Open() 
     Dim del As New SqlCommand(" delete from TableA where RefNo = '" & Request.QueryString("RefNo") & "'", con) 
     del.ExecuteNonQuery() 
     For i As Integer = 0 To displayCBL.Items.Count - 1 

      If displayCBL.Items(i).Selected Then 
       Dim cmd As New SqlCommand("Insert into TableA (RefNo,Text,InsertDate) values('" & Request.QueryString("RefNo") & "','" & displayCBL.Items(i).Value & "',getdate())", con) 
       cmd.ExecuteNonQuery() 

      End If 
     Next 
     con.Close() 
End Sub 

我發現我的子過程運行兩次，因此插入數據的兩倍（調試器和SQL Server事件探查證實了這一點）。有什麼我想念的嗎？

Answer 1

答案很簡單。上面的代碼稱爲事件TWICE。通過使onclick="Button1_Click"或Handles Button1.Click都是錯誤。選擇一個就足夠了。

你可以閱讀更多關於：

OnClick and Handles Caution: Events Firing Twice

ASP.Net OnClick vs Function() Handles buttonName.Click