How can I get a server-side control's tag? I'm guessing it's something like below:

```
TextBox textBox=new TextBox();

GetTag(TextBox textBox)
{
    ...
}

```

And the result is something like `<asp:TextBox />` (the control's design time tag).

When I change the control to `CheckBox` then the result should be something like `<asp:CheckBox />`.