I want that when the textbox is `visible = false`, the RequiredFieldValidator shouldn't run.

This is my aspx code:

```
<asp:TextBox runat="server" ID="txtAmt" MaxLength="7" Style="width: 100px;"/>
                    <asp:RequiredFieldValidator ValidationGroup="ln" runat="server" ControlToValidate="txtAmt"
                        Display="Dynamic" ErrorMessage="Required" />

```

Now in my code behind

```
 protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
           txtAmt.Visible = false;
        }
    }

```

and yet in my button click handler, when I do a `Page.IsValid`, it returns `false` if textbox is empty. Any idea how to solve this issue?