新手请教一个查询的问题，谢谢！

[COSByVal]

adodc1链接商品表adodc3链接租户表
商品表中有经营种类和单个品种这两列

combo8是经营种类，combo9是单个品种

想在form_load 中将商品表中所有经营种类等于combo8的单个品种 AddItem 到combo9中，但是报错：
实时错误 ‘91’
对象变量或with块变量未设置

请教各位大神，谢谢！


Me.Combo8.AddItem "水果"
Me.Combo8.AddItem "粮油"
Me.Combo8.AddItem "肉蛋禽"
Me.Combo8.AddItem "蔬菜"
Me.Combo8.AddItem "水产品"

Me.Adodc3.RecordSource = "select shangpinmingcheng from shangpin where shangpinzhonglei =" & "'" & Me.Combo8.Text & "'"
Do While Not Me.Adodc3.Recordset.EOF
Me.Combo9.AddItem Me.Adodc3.Recordset.Fields("shangpinmingcheng")
Loop

[of123]

Me.Combo8.AddItem "水果" Me.Combo8.AddItem "粮油" Me.Combo8.AddItem "肉蛋禽" Me.Combo8.AddItem "蔬菜" Me.Combo8.AddItem "水产品" Me.Combo8.ListIndex = 0 Me.Adodc3.RecordSource = "select shangpinmingcheng from shangpin where shangpinzhonglei =" & "'" & Me.Combo8.Text & "'" Me.Adodc3.Refresh Me.Combo9.Clear Do Until Me.Adodc3.Recordset.EOF Me.Combo9.AddItem Me.Adodc3.Recordset.Fields("shangpinmingcheng") Me.Combo9.Recordset.MoveNext Loop

[饮水需思源]

在form的load事件中没有combo8的默认值