asp.net – 在MS Access中双重插入？

Protected Sub btnSubmit_Click(ByVal sender As Object,ByVal e As System.EventArgs) Handles btnSubmit.Click

'Data collection'

'Define Connection'
    Dim myConn As New OleDbConnection
    myConn.ConnectionString = adsGrandmaster.ConnectionString
    myConn.Open()

'Insert command'
    Dim myIns1 As New OleDbCommand("INSERT INTO tableGrandmaster (date_received,prefix,course_number,title,new,changed,inactivate,end_date,credits,description,hours_lecture,hours_lec_lab,hours_lab,hours_total,related_instruction,repeat,challengeable,in_catalog,in_printed_schedule,core_course,core_name,program_elective,program_name,prereqs,coreqs,recommended,green_course,code,dept_code,division_code,changing_depts,acti_code,grading,general_ed,writing,social_science,math,information_literacy,arts_letters,science_computer,speech_comm,cultural_literacy,date_curriculum_approval,date_state_sent,date_state_approval,date_created) VALUES (?,?,?)",myConn)

'Insert parameters'

'Execute command'
    myIns1.ExecuteNonQuery()

'Close connection'
    myConn.Close()

更新：

我的.aspx.vb文件的最后一小部分：

'Execute command'
    myIns1.ExecuteNonQuery()

    Label1.Text = "Grandmaster submitted."

    'Close connection'
    myConn.Close()

End Sub

Protected Sub btnBack_Click(ByVal sender As Object,ByVal e As System.EventArgs) Handles btnBack.Click
    Response.Redirect("./index.htm")
End Sub
End Class

如果我将断点放在myIns1.ExecuteNonQuery()之前或之前,则不会插入任何内容.如果我将它放在myIns1.ExecuteNonQuery()之后,它会插入一次.如果我将它放在“End Sub”之后(在myConn.Close()下),它会插入两次.