下面的代码运行不报错，就是更新不到数据库

Dim new_yhm As String = CType(e.Item.Cells(2).Controls(0), TextBox).Text
        Dim new_mm As String = CType(e.Item.Cells(3).Controls(0), TextBox).Text
        Dim new_lx As String = CType(e.Item.Cells(4).Controls(0), TextBox).Text
        Dim updatestring As String
        Dim strConn As String
        strConn = "Server=MS-C8749356387F;database=pubs;trusted_connection=yes"
        myConn = New SqlConnection(strConn)
        updatestring = "update yhxx1 set yhm=@yhm,mm=@mm,lx=@lx where id=" & DataGrid1.DataKeys(e.Item.ItemIndex)
        Dim myCmd1 As SqlCommand = New SqlCommand(updatestring, myConn)
        myCmd1.Parameters.Add("@yhm", SqlDbType.VarChar, 50).Value = new_yhm
        myCmd1.Parameters.Add("@mm", SqlDbType.VarChar, 50).Value = new_mm
        myCmd1.Parameters.Add("@lx", SqlDbType.VarChar, 50).Value = new_lx
        myConn.Open()
        myCmd1.ExecuteNonQuery()
        myConn.Close()
        DataGrid1.EditItemIndex = -1
        bind_data()