Does C# have an equivalent to JavaScript's encodeURIComponent()?

Question

In JavaScript:

encodeURIComponent("©√") == "%C2%A9%E2%88%9A"

Is there an equivalent for C# applications? For escaping HTML characters I used:

txtOut.Text = Regex.Replace(txtIn.Text, @"[\u0080-\uFFFF]",
    m => @"&#" + ((int)m.Value[0]).ToString() + ";");

But I'm not sure how to convert the match to the correct hexadecimal format that JS uses. For example this code:

txtOut.Text = Regex.Replace(txtIn.Text, @"[\u0080-\uFFFF]",
    m => @"%" + String.Format("{0:x}", ((int)m.Value[0])));

Returns "%a9%221a" for "©√" instead of "%C2%A9%E2%88%9A". It looks like I need to split the string up into bytes or something.

Edit: This is for a windows app, the only items available in System.Web are: AspNetHostingPermission, AspNetHostingPermissionAttribute, and AspNetHostingPermissionLevel.

Solution 1

Uri.EscapeDataString or HttpUtility.UrlEncode is the correct way to escape a string meant to be part of a URL.

Take for example the string "Stack Overflow":

• HttpUtility.UrlEncode("Stack Overflow") --> "Stack+Overflow"

• Uri.EscapeUriString("Stack Overflow") --> "Stack%20Overflow"

• Uri.EscapeDataString("Stack + Overflow") --> Also encodes "+" to "%2b" ---->Stack%20%2B%20%20Overflow

Only the last is correct when used as an actual part of the URL (as opposed to the value of one of the query string parameters)

Solution 2

HttpUtility.HtmlEncode / Decode
HttpUtility.UrlEncode / Decode

You can add a reference to the System.Web assembly if it's not available in your project

Solution 3

I tried to do full compatible analog of javascript's encodeURIComponent for c# and after my 4 hour experiments I found this

c# CODE:

string a = "!@#$%^&*()_+ some text here али мамедов баку";
a = System.Web.HttpUtility.UrlEncode(a);
a = a.Replace("+", "%20");

the result is: !%40%23%24%25%5e%26*()_%2b%20some%20text%20here%20%d0%b0%d0%bb%d0%b8%20%d0%bc%d0%b0%d0%bc%d0%b5%d0%b4%d0%be%d0%b2%20%d0%b1%d0%b0%d0%ba%d1%83

After you decode It with Javascript's decodeURLComponent();

you will get this: !@#$%^&*()_+ some text here али мамедов баку

Thank You for attention

Solution 4

System.Uri.EscapeUriString() didn't seem to do anything, but System.Uri.EscapeDataString() worked for me.

Solution 5

Try Server.UrlEncode(), or System.Web.HttpUtility.UrlEncode() for instances when you don't have access to the Server object. You can also use System.Uri.EscapeUriString() to avoid adding a reference to the System.Web assembly.

View more solutions

Comments

[travis]

I should've been more specific: This is for a windows app, the only items available in System.Web are: AspNetHostingPermission, AspNetHostingPermissionAttribute, and AspNetHostingPermissionLevel.

[David Thibault]

You can add a reference to the System.Web assembly

[travis]

The Server object is inaccessible from a windows app

[travis]

The main issue I was having was not having a reference to System.Web in my solution, but I wasn't aware of EscapeUriString, thanks!

[jwaliszko]

In contrast to encodeURIComponent(), Uri.EscapeUriString() doesn't encode "+" to "%2b". Use Uri.EscapeDataString() instead.

[Toland Hon]

Uri.EscapeUriString() didn't do anything for me, but I was able to properly url-encode the strings using Uri.EscapeDataString()

[Steven De Kock]

Use WebUtility instead of HttpUtility to avoid having to reference System.Web. HttpUtility doesn't exist in .NET Core.

[Brandon Paddock]

HtmlEncoding is an entirely different thing. UrlEncode is a non-sensical API which should never be used. It doesn't make sense to encode an entire URL (unless you actually want to encode its value to use as a parameter - but that's not what this does). The point of encoding/escaping is that you're conveying that a reserved character should be passed through without its usual meaning (e.g. that ? identifies the query, or & separates query parameters). This requires knowledge that UrlEncode does not and cannot have.

[Timo]

@Steve Would you consider making your last paragraph bold? It seems to be the most important thing to know on this page, and it needs more visibility.

[mklement0]

Works, but you can simply use Uri.EscapeDataString("!@#$%^&*()_+ some text here али мамедов баку") instead.

[mklement0]

@TolandHon: Indeed. The reason is that Uri.EscapeUriString() corresponds to JavaScript's encodeURI() - which preserves URI-reserved chars. such as /, &, ... as-is (plus #), whereas - as you've discovered, it is Uri.EscapeDataString() that corresponds to JavaScript's encodeURIComponent().

[Jason]

Also see this answer for more explanation on the difference between Uri.EscapeUriString and Uri.EscapeDataString: stackoverflow.com/questions/4396598/…

[Jason]

See this answer for more explanation on the difference between HttpUtility.UrlEncode and HttpUtility.UrlPathEncode stackoverflow.com/questions/4145823/…

[nothingisnecessary]

UrlPathEncode and EscapeUriString do not encode ampersand & but Uri.EscapeDataString and HttpUtility.UrlEncode() do

[Øystein Kolsrud]

Actually, Uri.EscapeDataString encodes the characters '(' and ')' while HttpUtility.UrlEncode does not.

[omostan]

Kudos to Steve for providing this excellent answer and Tim for the edited version. This work well and save my nerves after a very long search. To all of you who always contribute to this very useful platform, I say thank you!