How do I specify that I want my hyperlink to always be absolute path?

I have this link of code where I populate a hyperlink with an address at runtime from the database.

    <asp:HyperLink ID="HyperLink1" runat="server" Target="_blank" 
NavigateUrl='<%#Eval("Source") %>'><%#Eval("Source") %></asp:HyperLink>

The problem is that it's treating the link as relative. so if the link is yahoo.com, it'll go to

http://localhost/yahoo.com

开发者_Go百科or something to that effect.

If my link source is http://www.yahoo.com, that will work, but I cannot guarantee that the links may or may not have the http:// at the start.

How can I get it to always treat it as an absolute URL.

---

You can try something like this

NavigateUrl='<%# GetUrl(Eval("Source")) %>'>

with

public string GetUrl(object source)
{
    if(source != null)
    {
        string str = source.ToString();
        return str.StartsWith("http://", StringComparison.InvariantCultureIgnoreCase) ?
                           str : 
                           string.Format("http://{0}",str);
    }  
    return string.Empty;
}