含代码 VB.NET动态生成DROPDOWNLIST 里的数据 ，请问我错在哪里？

Dim StrSkill As String
Dim objDataTalbe As DataTable
' Dim Tablerows As DataRow
Dim ddl As DropDownList

' 对每行数据遍历
For Each objRow As GridViewRow In Me.GridView1.Rows

StrSkill = objRow.Cells(0).Text

objMDL = objBLL.getDdlSkillLevel(StrSkill)

objDataTalbe = objMDL.ddlSkillLevel ‘得到了一列名为'SKILL_LEVEL'的数据

' 获得在GRIDVIEW里面的下拉框
ddl = DirectCast(Me.GridView1.FindControl("classLevel"), DropDownList)
’在这里绑定数据 出异常 ，Object reference not set to an instance of an object.
ddl.DataSource = objDataTalbe
ddl.DataTextField = "skill_level"
ddl.DataValueField = "skill_level"

Next

请问 我通过这样遍历 GRIDVIEW 能实现 对下拉框的动态生成吗

我这样做对不对



[解决办法]
ddl = DirectCast(Me.GridView1.FindControl("classLevel"), DropDownList)
改成这样 ddl = DirectCast(objRow.FindControl("classLevel"), DropDownList)