Outputting a manipulated QueryString in C#

Question

Using the following code I get a nice formatted string:

Request.QueryString.ToString 

Gives me something like: &hello=world&microsoft=sucks

But when I use this code to clone the collection to another object (of the same type) I get the Type() back from the ToString() method instead.

System.Collections.Specialized.NameValueCollection variables = new System.Collections.Specialized.NameValueCollection(Request.QueryString);
if (!string.IsNullOrEmpty(variables["sid"]))
    variables.Remove("sid");
Response.Write(variables.ToString());

Is there a tidier way to output it rather than looking and building the string manually?

Answer 1

HttpValueCollection is internal, but you can use "var" to declare it without extract it with reflector.

var query = HttpUtility.ParseQueryString(Request.Url.Query);
query["Lang"] = myLanguage; // Add or replace param
string myNewUrl = Request.Url.AbsolutePath + "?" + query;

Answer 2

You can also use Reflector to extract the HttpValueCollection class into your own, and use it then.

Answer 3

Because it is actually a special NVC that is of type HTTPValueCollection. So when you call .ToString on it, it knows how to format it correctly.

Answer 4

Why do you want to copy the QueryString collection into a new NameValueCollection?

    if (!string.IsNullOrEmpty(Request.QueryString["sid"]))
        Request.QueryString.Remove("sid");

Yes indeed, i am wrong, it is read only. So the essence is to use the Remove Method on your NameValuecollection:

System.Collections.Specialized.NameValueCollection variables = new System.Collections.Specialized.NameValueCollection(Request.QueryString);
if (!string.IsNullOrEmpty(variables["sid"]))
    variables.Remove("sid");