Dictionary to Querystring convertor

Dictionary2QueryStringExtension.cs

using System.Collections.Generic;
using System.Linq;
using System.Text;

public static class CollectionExtensions
{
    public static string ToQueryString(this IDictionary<string, string> dict)
    {
        if (dict.Count == 0) return string.Empty;

        var buffer = new StringBuilder();
        int count = 0;
        bool end = false;

        foreach (var key in dict.Keys)
        {
            if (count == dict.Count - 1) end = true;

            if (end)
                buffer.AppendFormat("{0}={1}", key, dict[key]);
            else
                buffer.AppendFormat("{0}={1}&", key, dict[key]);

            count++;
        }

        return buffer.ToString();
    }
}