DropDownList another way to set the selected item

In what we are doing according to a value, to compare all the values of the DropDownList, if the equality is selected, our usual practice is certainly:
Suppose we write the following code in the Click event of the button, which means that the current DropDownList selected value is written to the cookie.
protected void Button1_Click (object sender, EventArgs e)
{
HttpCookie HC = new HttpCookie ("Interfacestyle", this. Dropdownlist1.selectedvalue);
Hc. Expires = DateTime.Now.AddMonths (1);
RESPONSE.COOKIES.ADD (HC);
And then read it from the cookie in Page_Load, and if there is one in the cookie, the DropDownList in the protected void Page_Load is selected (object sender, EventArgs E
{
if (! Page.IsPostBack)
{
NameValueCollection NVC = (NameValueCollection) configurationmanager.getsection ("Interfacestyle");

for (int i = 0; i < NVC. Count; i + +)
{
this. DROPDOWNLIST1.ITEMS.ADD (New ListItem (NVC[NVC). Getkey (i)], NVC. Getkey (i)));
}
HttpCookie HC = request.cookies["Interfacestyle"];
if (HC!= null)
{
this. Dropdownlist1.selectedvalue = HC. Value;
}
}

This is certainly true, and I'm going to talk about the following procedure:
protected void Page_Load (object sender, EventArgs e)
{
if (! Page.IsPostBack)
{
NameValueCollection NVC = (NameValueCollection) configurationmanager.getsection ("Interfacestyle");

for (int i = 0; i < NVC. Count; i + +)
{
this. DROPDOWNLIST1.ITEMS.ADD (New ListItem (NVC[NVC). Getkey (i)], NVC. Getkey (i)));
}
HttpCookie HC = request.cookies["Interfacestyle"];
if (HC!= null)
{
ListItem Li = This . DropDownList1.Items.FindByValue (HC. Value);
if (Li!= null )
{
Li. Selected = True ; ;
}
}
}

}
Bold parts, this approach, although troublesome, but we think, if the first method, if the cookie is not empty, and, the value in the cookie is not DropDownList in the value, it is conceivable that there will be exceptions, and the second approach to avoid this anomaly.