樣版欄位內的Calendar被點選後，希望把值帶給另一個textbox樣版欄位

若樣版欄位內的Calendar被點選後，希望把值帶給另一個textbox樣版欄位，
若網頁與程式碼沒有分離，當Calendar被點選後，會發生的事情如下
Protected Sub Calendar1_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs)

Dim tb As TextBox = Me.FormView1.FindControl("HireDateTextBox")
tb.Text = sender.SelectedDate.ToString()

End Sub
如果網頁與程式碼分離，當Calendar被點選後，會發生的事情如下
Protected Sub Calendar2_SelectionChanged(ByVal sender As Object, ByVal e As System.EventArgs)

Dim SenderCalendar As Calendar = CType(sender, Calendar)

Dim tb As TextBox = Me.FormView1.FindControl("HireDateTextBox")
tb.Text = SenderCalendar.SelectedDate.ToString()

End Sub

Calendar本身也得作型別轉換