如果添加记录被取消，请返回添加另一个记录

Question

im在我单击消息框时添加记录的问题，然后回答是否然后取消它并添加另一个记录，但是iM尚未初始化连接消息，我的代码谢谢我的代码你。

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Try
        Dim reader As SqlDataReader
        conn.Open()
        Dim bday As String
        bday = adyear.Text & "-" & admonth.Text & "-" & adday.Text

        If adfirstname.Text.Length < 2 Then
            MessageBox.Show("Firstname is too short")
        End If
        Dim exist As String
        exist = "select * from record where firstname='" & adfirstname.Text & "'" & " and lastname='" & adlastname.Text & "';"
        cmd = New SqlCommand(exist, conn)
        reader = cmd.ExecuteReader
        If reader.HasRows = True Then
            If MsgBox("THE MEMBER YOU ARE TRYING TO ADD HAS AN SAME FIRSTNAME AND LASTNAME IN THE RECORD DO YOU WISH TO CONTINUE ?", MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then
            ElseIf adage.Text < 18 Then
                If MsgBox("The member is less than 18 years old is this an intern?", MsgBoxStyle.YesNo) = MsgBoxResult.Yes Then
                    Dim add As String
                    add = "insert into record(firstname,middlename,lastname,birthday,age,jobposition)" & _
                         "values(" & _
                         "'" & adfirstname.Text & "'," & _
                         "'" & admiddlename.Text & "'," & _
                         "'" & adlastname.Text & "'," & _
                         "'" & bday & "'," & _
                         "'" & adage.Text & "'," & _
                         "'" & adjobposition.Text & "');"
                    cmd = New SqlCommand(add, conn)
                    cmd.ExecuteNonQuery()
                    MessageBox.Show("Added Complete")
                Else
                    MsgBox("Action is Terminated")
                    ' code for return to adding and stop the messagebox of the connection has not been initialized

                End If
            End If
        End If
            conn.Close()
    Catch ex As Exception
        MessageBox.Show(ex.Message)
    Finally
        conn.Dispose()
    End Try
End Sub

结束类

Answer 1

好吧，因为它看起来conn是一个表单级别对象，您需要调用

conn = New SqlConnection(<connection string>) 

在您可以使用它打开连接之前。鉴于您致电

conn.Dispose()

要在最后块中销毁CONN实例，似乎您不会长时间保持打开的连接。