rs。意外地循环多次

Question

在我的项目中，我编写了一个程序来显示已加入特定类的所有成员。将数据添加到我的列表框中时，如果返回了2个结果，则这两个相同的结果将多次添加到列表框中，我只希望将结果添加一次。有没有人知道为什么我的记录被添加了太多次？

Private Sub DisplayMembersOnClass(CurrentClassID As Integer)
    If CurrentClassID <> -1 Then
        If Dbconnect() Then
            Dim SQLCMD As New OleDbCommand
            With SQLCMD
                .Connection = cn
                .CommandText = "Select * " &
                    "From MembersClass,Class, Members " &
                    "Where MembersClass.ClassID = @CurrentClassID and Members.MemberID = MembersClass.MemberID"
                .Parameters.AddWithValue("@CurrentClassID", CurrentClassID)
            End With
            Dim rs As OleDbDataReader = SQLCMD.ExecuteReader
            While rs.Read

                Dim firstname As String = rs("FirstName")
                Dim secondname As String = rs("SecondName")
                Dim MemberName = (firstname) & " " & (secondname)
                Dim DisplayValue As String = (MemberName) & " " & rs("Members.MemberID")
                Dim classitem As New ListBoxData(DisplayValue, & "ID - " rs("Class.ClassID"))

                ListBoxMembersOnClass.Items.Add(classitem)
            End While
            rs.Close()
        End If
    End If

End Sub