救命啊，DATAGRID中更新数据出现“指定控件转换无效”

哪位大侠给指导一下，谢谢了！
代码：


Private Sub ResourceInList_UpdateCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs) Handles ResourceInList.UpdateCommand
Dim shebeibianhao, shebeimingcheng, shebeiguige, lingyongbumen, lingyongren, lingyongriqi, bdbh As TextBox
bdbh = e.Item.Cells(0).Controls(0)
shebeibianhao = e.Item.Cells(1).Controls(0)
shebeimingcheng = e.Item.Cells(2).Controls(0)
shebeiguige = e.Item.Cells(3).Controls(0)
lingyongbumen = e.Item.Cells(4).Controls(0)
lingyongren = e.Item.Cells(5).Controls(0)
lingyongriqi = e.Item.Cells(6).Controls(0)

Dim myConn As New SqlClient.SqlConnection
Dim myCmd As New SqlClient.SqlCommand
Dim myDataAdapter As New SqlClient.SqlDataAdapter
Dim connstr As String
connstr = ConfigurationSettings.AppSettings("dsn")
myConn.ConnectionString = connstr
myConn.Open()

myCmd.CommandText = "update tblshebeilingyong set shebeibianhao=@shebeibianhao,shebeimingcheng=@shebeimingcheng,shebeiguige=@shebeiguige,lingyongbumen=@lingyongbumen,lingyongyuangong=@lingyongren,lingyongriqi=@lingyongriq where bdbh=@bdbh"



myCmd.Parameters.Clear()
myCmd.Parameters.Add(New SqlClient.SqlParameter("@shebeibianhao", SqlDbType.VarChar, 50))
myCmd.Parameters.Add(New SqlClient.SqlParameter("@shebeimingcheng", SqlDbType.VarChar, 50))
myCmd.Parameters.Add(New SqlClient.SqlParameter("@shebeiguige", SqlDbType.VarChar, 200))
myCmd.Parameters.Add(New SqlClient.SqlParameter("@shebeizhuangtai", SqlDbType.VarChar, 50))
myCmd.Parameters.Add(New SqlClient.SqlParameter("@lingyongriqi", SqlDbType.SmallDateTime, 4))
myCmd.Parameters.Add(New SqlClient.SqlParameter("@lingyongbumen", SqlDbType.VarChar, 50))
myCmd.Parameters.Add(New SqlClient.SqlParameter("@lingyongren", SqlDbType.VarChar, 50))
myCmd.Parameters.Add(New SqlClient.SqlParameter("@bdbh", SqlDbType.VarChar, 50))


myDataAdapter.SelectCommand.Parameters("@shebeibianhao").Value = Trim(shebeibianhao.Text)
myDataAdapter.SelectCommand.Parameters("@shebeimingcheng").Value = Trim(shebeimingcheng.Text)
myDataAdapter.SelectCommand.Parameters("@shebeiguige").Value = Trim(shebeiguige.Text)
myDataAdapter.SelectCommand.Parameters("@lingyongriqi").Value = Trim(lingyongriqi.Text)
myDataAdapter.SelectCommand.Parameters("@lingyongbumen").Value = Trim(lingyongbumen.Text)
myDataAdapter.SelectCommand.Parameters("@lingyongren").Value = Trim(lingyongyuangong.Text)
myDataAdapter.SelectCommand.Parameters("@bdbh").Value = ResourceInList.DataKeys.Item(e.Item.ItemIndex)

myConn.Open()
myCmd.ExecuteNonQuery()
myConn.Close()
ResourceInList.EditItemIndex = -1
BindResourceInData()



End Sub
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指定的转换无效。
说明: 执行当前 Web 请求期间，出现未处理的异常。请检查堆栈跟踪信息，以了解有关该错误以及代码中导致错误的出处的详细信息。

异常详细信息: System.InvalidCastException: 指定的转换无效。

源错误:


行 192： Private Sub ResourceInList_UpdateCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.DataGridCommandEventArgs) Handles ResourceInList.UpdateCommand
行 193： Dim shebeibianhao, shebeimingcheng, shebeiguige, lingyongbumen, lingyongren, lingyongriqi, bdbh As TextBox
行 194： bdbh = e.Item.Cells(0).Controls(0)
行 195： shebeibianhao = e.Item.Cells(1).Controls(0)
行 196： shebeimingcheng = e.Item.Cells(2).Controls(0)