ASP.NET: URI handling

Question

I'm writing a method which, let's say, given 1 and hello should return http://something.com/?something=1&hello=en.

I could hack this together pretty easily, but what abstraction functionality does ASP.NET 3.5 provide for building URIs? I'd like something like:

URI uri = new URI("~/Hello.aspx"); // E.g. ResolveUrl is used here
uri.QueryString.Set("something", "1");
uri.QueryString.Set("hello", "en");
return uri.ToString(); // /Hello.aspx?something=1&hello=en

I found the Uri class which sounds highly relevant, but I can't find anything which does the above really. Any ideas?

(For what it's worth, the order of the parameters doesn't matter to me.)

Answer 1

Edited to correct massively incorrect code

Based on this answer to a similar question you could easily do something like:

UriBuilder ub = new UriBuilder();

// You might want to take more care here, and set the host, scheme and port too
ub.Path = ResolveUrl("~/hello.aspx"); // Assumes we're on a page or control.

// Using var gets around internal nature of HttpValueCollection
var coll = HttpUtility.ParseQueryString(string.Empty);

coll["something"] = "1";
coll["hello"] = "en";

ub.Query = coll.ToString();
return ub.ToString();
// This returned the following on the VS development server:
// http://localhost/Hello.aspx?something=1&hello=en

This will also urlencode the collection, so:

coll["Something"] = "1";
coll["hello"] = "en&that";

Will output:

Something=1&hello=en%26that 

Answer 2

As far I know nothing here. So everybody has its own implementation.

Example from LinqToTwitter.

    internal static string BuildQueryString(IEnumerable<KeyValuePair<string, string>> parameters)
    {
        if (parameters == null)
        {
            throw new ArgumentNullException("parameters");
        }

        StringBuilder builder = new StringBuilder();
        foreach (var pair in parameters.Where(p => !string.IsNullOrEmpty(p.Value)))
        {
            if (builder.Length > 0)
            {
                builder.Append("&");
            }

            builder.Append(Uri.EscapeDataString(pair.Key));
            builder.Append("=");
            builder.Append(Uri.EscapeDataString(pair.Value));
        }

        return builder.ToString();
    }

UPDATE:

You can also create extension method:

public static UriBuilder AddArgument(this UriBuilder builder, string key, string value)
{
 #region Contract

 Contract.Requires(builder != null);
 Contract.Requires(key != null);
 Contract.Requires(value != null);

 #endregion

 var query = builder.Query;

 if (query.Length > 0)
 {
      query = query.Substring(1) + "&";
 } 

 query += Uri.EscapeDataString(key) + "="
      + Uri.EscapeDataString(value);

 builder.Query = query;

 return builder;
}

And usage:

var b = new UriBuilder();
b.AddArgument("test", "test");

Please note that everything here is untested.