```
private void Button1_OnClick(object sender, EventeArgs e)
{
    Response.Redirect(myselect.SelectedValue.ToString(), true);
}

```

Above is my code, I already put a breakpoint on `.SelectedValue` and it's recognizing the value, but when I click on the button it shows this message:

![Error Picture](https://i.stack.imgur.com/8p1r5.png)