How to convert NameValueCollection to a (Query) String

Most ASP.NET developers know that you can get a key/value pair string from the Request.QueryString object (via the .ToString() method). However that functionality isn’t the same for a generic NameValueCollection object (of which Request.QueryString is derived from).

So how do you take a NameValueCollection object and get a nicely formatted key/value pair string? (i.e. “key1=value1&key2=value2“) … Here’s a method I wrote a while ago:

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1. /// <summary>
2. /// Constructs a QueryString (string).
3. /// Consider this method to be the opposite of "System.Web.HttpUtility.ParseQueryString"
4. /// </summary>
5. /// <param name="nvc">NameValueCollection</param>
6. /// <returns>String</returns>
7. public static String ConstructQueryString(NameValueCollection parameters)
8. {
9. List<String> items = new List<String>();
10. 
    
11. foreach (String name in parameters)
12. items.Add(String.Concat(name, "=", System.Web.HttpUtility.UrlEncode(parameters[name])));
13. 
    
14. return String.Join("&", items.ToArray());
15. }

/// <summary>

/// Constructs a QueryString (string).
/// Consider this method to be the opposite of "System.Web.HttpUtility.ParseQueryString"
/// </summary>
/// <param name="nvc">NameValueCollection</param>
/// <returns>String</returns>
public static String ConstructQueryString(NameValueCollection parameters)
{
List<String> items = new List<String>();

foreach (String name in parameters)
 items.Add(String.Concat(name, "=", System.Web.HttpUtility.UrlEncode(parameters[name])));

return String.Join("&", items.ToArray());
}

Just in case you didn’t know about the System.Web.HttpUtility.ParseQueryString method, it’s a quick way of converting a query (key/value pairs) string back into a NameValueCollection.

From : http://blog.leekelleher.com/2008/06/06/how-to-convert-namevaluecollection-to-a-query-string/