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

Answer 1

Just combined answers=>

public static class UriBuilderExtensions
{
    public static void AddQueryArgument(this UriBuilder b, string key, string value)
    {
        key = Uri.EscapeDataString(key);
        value = Uri.EscapeDataString(value);

        var x = HttpUtility.ParseQueryString(b.Query);
        if (x.AllKeys.Contains(key)) throw new ArgumentNullException
                ("Key '{0}' already exists!".FormatWith(key));
        x.Add(key, value);
        b.Query = x.ToString();
    }

    public static void EditQueryArgument(this UriBuilder b, string key, string value)
    {
        key = Uri.EscapeDataString(key);
        value = Uri.EscapeDataString(value);

        var x = HttpUtility.ParseQueryString(b.Query);
        if (x.AllKeys.Contains(key))
            x[key] = value;
        else throw new ArgumentNullException
                ("Key '{0}' does not exists!".FormatWith(key));
        b.Query = x.ToString();
    }

    public static void AddOrEditQueryArgument(this UriBuilder b, string key, string value)
    {
        key = Uri.EscapeDataString(key);
        value = Uri.EscapeDataString(value);

        var x = HttpUtility.ParseQueryString(b.Query);
        if (x.AllKeys.Contains(key))
            x[key] = value;
        else
            x.Add(key, value);
        b.Query = x.ToString();
    }

    public static void DeleteQueryArgument(this UriBuilder b, string key)
    {
        key = Uri.EscapeDataString(key);
        var x = HttpUtility.ParseQueryString(b.Query);
        if (x.AllKeys.Contains(key))
            x.Remove(key);
        b.Query = x.ToString();
    }
}

Half baked code. But should work well enough.