Programmatically resolving ~ URL's to the Virtual Root using ResolveURL()

It's common knowledge that a control, when Runat="server" will resolve it's src or href attribute to a virtual root when the URL starts with ~/

For example:

<a href="~/Customers/Profile.aspx" Runat="server">Profile</a>

will become:

<a href="http://yourdomain.com/site/Customers/Profile.aspx" Runat="server">Profile</a>

How do we do this programmatically?

The base WebControl class exposes a method named ResolveURL(). This method accepts a url such as "~/Customers/Profile.aspx" and returns the real url, starting from your site's virtual root.

To get to this functionality you can use the following pattern:

string url = Page.ResolveClientUrl("~/Customers/Profile.aspx");

..or..

string url = VirtualPathUtility.ToAbsolute("~/Customers/Profile.aspx");

..or..

Image x = new Image();
string url = x.ResolveUrl("~/Customers/Profile.aspx");

Author Paul Hayman

Paul is the COO of kwiboo ltd and has more than 20 years IT consultancy experience. He has consulted for a number of blue chip companies and has been exposed to the folowing sectors: Utilities, Telecommunications, Insurance, Media, Investment Banking, Leisure, Legal, CRM, Pharmaceuticals, Interactive Gaming, Mobile Communications, Online Services.

Paul is the COO and co-founder of kwiboo (http://www.kwiboo.com/) and is also the creator of GeekZilla.

Comments

Anonymous said:

Excellent article.... Really helped me out

12/Jul/2006 15:33 PM

Vladek said:

Yes, it's very handy method.

Well, here is a method to resolve URLs for HTML tags, which are not or cannot be marked with runat="server":

<a href="<%= ResolveUrl("~/Customers/Profile.aspx") %>">Profile</a>

Just use <%=%> to place small pieces of code into HTML.

19/Jun/2007 12:17 PM

said:

JIT information. Great work, and thanks!

11/Oct/2007 17:16 PM

Me said:

It does not add the server, the output is more like

<a href="/site/Customers/Profile.aspx" Runat="server">Profile</a>

14/Feb/2008 16:43 PM

Jack said:

Thanks for your tip on the VirtualPathUtility. I had to implement something like this for a WebService, but I needed the full url to the root. Here's my C# code:

string path = VirtualPathUtility.ToAbsolute("~/setup.msi");

// this should return the end portion of the url (ie: /test/setup.msi)

// so we should be able to use this to find our actual url:

string baseurl = Context.Request.Url.GetComponents(UriComponents.SchemeAndServer, UriFormat.Unescaped);

string url = Config.UriCombine(baseurl, path);

return url;

The helper method UriCombine (like Path.Combine):

public static string UriCombine(string str, params string[] param)

{

    string b = str;

    for (int i = 0; i < param.Length; i++)

    {

        if (!b.EndsWith("/"))

        {

            b = b + "/";

        }

        Uri uri = new Uri(b);

        b = new Uri(uri, param[i]).AbsoluteUri;

    }

    return new Uri(b).AbsoluteUri;

}

01/Jan/2011 08:24 AM

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