How do I decode a URL parameter using C#?

Question

How can I decode an encoded URL parameter using C#?

For example, take this URL:

my.aspx?val=%2Fxyz2F

Laundry

Hey Tom, couldn't ask on the actual post because it was removed, but did you ever find a solution to Latest Chrome 117.0.5938.89 no more Prints out properly the html page due scaling differences [closed]? – Motherless

Please vote for a bug ticket in chrome to solve it – Laundry

Answer 1

string decodedUrl = Uri.UnescapeDataString(url)

or

string decodedUrl = HttpUtility.UrlDecode(url)

Url is not fully decoded with one call. To fully decode you can call one of this methods in a loop:

private static string DecodeUrlString(string url) {
    string newUrl;
    while ((newUrl = Uri.UnescapeDataString(url)) != url)
        url = newUrl;
    return newUrl;
}

Tutankhamen

@Tutankhamen Thanks for that! I didn't know it didn't fully work with just one call! I ran Uri.UnescapeDataString twice and got what I wanted!! :D – Sexology

IMHO better than the accpeted answer because your first suggestion also works in Portable Class Libaries (PCLs) – Locomotive

best answer! but consider how your params are nested before you fully decode. e.g. a param value could be an encoded URL which itself has a param with another encoded URL, If you fully decode it in one go, you won't be able to tell what was what anymore. it would be like yanking all the parens out of an algebra statement. a=((b+c)*d) if you fully unescape it, the meaning of components can be lost a=b+c*d – Levant

UnescapeDataString is not sufficient as it will not handle several cases (for instance parameters in a URL that contain a space use '+' but UnescapeDataString intentionally doesn't convert those to spaces). Uri handles more than just URL, as the question is asking about URL we should use HttpUtility.UrlDecode – Depopulate

Answer 2

Server.UrlDecode(xxxxxxxx)

Pede

which namespace? – Affiche

@PolinaC System.Web.HttpServerUtilityBase, but that should already be imported in ASP.NET MVC. – Doig

Answer 3

Have you tried HttpServerUtility.UrlDecode or HttpUtility.UrlDecode?

Uniformed

To access the HttpServerUtility.UrlDecode which is an instance method one should use HttpContext.Current.Server.UrlDecode. – Classmate

Answer 4

Try:

var myUrl = "my.aspx?val=%2Fxyz2F";
var decodeUrl = System.Uri.UnescapeDataString(myUrl);

Incitement

Answer 5

Try this:

string decodedUrl = HttpUtility.UrlDecode("my.aspx?val=%2Fxyz2F");

Sarisarid

I get: Failed to decrypt using provider 'EncryptionProvider'. Error message from the provider: The RSA key container could not be opened. – Precess