reading a cookie to show a panel

I am trying to read a cookie from the user computer, if this cookie existing , then i will show him a pa开发者_C百科nel1 , if not , panel2 will be visible.

i guess this work will be done in the page_load code block , so here is my code

 protected void Page_Load(object sender, EventArgs e)
{


    if (Request.Cookies["test"].Value)
    {
        Panel1.Visible = false;
        Panel2.Visible = true;
    }

}

the problem is it highlighted Request.Cookies["test"].Value as an erorr , saying

"Error> Cannot implicitly convert type 'string' to 'bool'"

Any suggestions ?

using c# , visiual studio 2010 express, web forms.

First of all Request.Cookies["test"] may be null (if there is no cookie), so you need to test for that.

Request.Cookies["test"].Value returns a string, not a boolean. The if statement can only operate on boolean expressions.

You can use string.IsNullOrWhiteSpace to check the value of the cookies - it will return true if there is no value or if it only contains whitespace and false otherwise:

if (Request.Cookies["test"] != null && !string.IsNullOrWhiteSpace(Request.Cookies["test"].Value))
{
    Panel1.Visible = false;
    Panel2.Visible = true;
}