How to build a query string for a URL in C#?

Question

A common task when calling web resources from a code is building a query string to including all the necessary parameters. While by all means no rocket science, there are so

Answer 1

A quick extension method based version:

class Program
{
    static void Main(string[] args)
    {
        var parameters = new List>
                             {
                                 new KeyValuePair("A", "AValue"),
                                 new KeyValuePair("B", "BValue")
                             };

        string output = "?" + string.Join("&", parameters.ConvertAll(param => param.ToQueryString()).ToArray());
    }
}

public static class KeyValueExtensions
{
    public static string ToQueryString(this KeyValuePair obj)
    {
        return obj.Key + "=" + HttpUtility.UrlEncode(obj.Value);
    }
}

You could use a where clause to select which parameters get added to the string.