主题：[求助]窗口中的动态列表项目 的一个问题?

Dim cmb As WinForm.ComboBox = e.form.Controls("ComboBox1")
cmb.ComboList = DataTables("表A").GetComboListString("型号")

2、在ComboBox2的Enter事件中加入代码：

Dim cmb As WinForm.ComboBox = e.Sender
Dim str As string = e.Form.Controls("ComboBox1").Value
cmb.ComboList = DataTables("表A").GetComboListString("规格", "型号 = '" & str & "'")

3、最后在ComboBox3的Enter事件中加入代码：

Dim cmb As WinForm.ComboBox = e.Sender
Dim str As String = e.Form.Controls("ComboBox2").Value
cmb.ComboList = DataTables("表A").GetComboListString("颜色", "规格 = '" & str & "'")

若表是空的,没加载,数据在后台,现在要问是若从后台进行,代码该如何写?