NameValueCollection to postData

Extensions.cs

using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web;

public static class Extensions
{
    public static string ToPostData(this NameValueCollection @this)
    {
        StringBuilder post = new StringBuilder();
        foreach (var item in @this.AllKeys)
        {
            post.AppendFormat("&{0}={1}", item, HttpUtility.UrlEncode(@this[item]));
        }
        string postData = post.ToString().Trim('&');
        return postData;
    }
}