A Query String Collection is used to retrieve the variable values in the HTTP query string. If we want to transfer a large amount of data then we can't use the Request. QueryString. Query Strings are also generated by form submission or can be used by a user typing a query into the address bar of the browsers.
The QueryString collection is used to retrieve the variable values in the HTTP query string.
There's a built-in .NET utility for this: HttpUtility.ParseQueryString
// C#
NameValueCollection qscoll = HttpUtility.ParseQueryString(querystring);
' VB.NET
Dim qscoll As NameValueCollection = HttpUtility.ParseQueryString(querystring)
You may need to replace querystring
with new Uri(fullUrl).Query
.
HttpUtility.ParseQueryString will work as long as you are in a web app or don't mind including a dependency on System.Web. Another way to do this is:
NameValueCollection queryParameters = new NameValueCollection();
string[] querySegments = queryString.Split('&');
foreach(string segment in querySegments)
{
string[] parts = segment.Split('=');
if (parts.Length > 0)
{
string key = parts[0].Trim(new char[] { '?', ' ' });
string val = parts[1].Trim();
queryParameters.Add(key, val);
}
}
A lot of the answers are providing custom examples because of the accepted answer's dependency on System.Web. From the Microsoft.AspNet.WebApi.Client NuGet package there is a UriExtensions.ParseQueryString, method that can also be used:
var uri = new Uri("https://stackoverflow.com/a/22167748?p1=6&p2=7&p3=8");
NameValueCollection query = uri.ParseQueryString();
So if you want to avoid the System.Web dependency and don't want to roll your own, this is a good option.
I wanted to remove the dependency on System.Web so that I could parse the query string of a ClickOnce deployment, while having the prerequisites limited to the "Client-only Framework Subset".
I liked rp's answer. I added some additional logic.
public static NameValueCollection ParseQueryString(string s)
{
NameValueCollection nvc = new NameValueCollection();
// remove anything other than query string from url
if(s.Contains("?"))
{
s = s.Substring(s.IndexOf('?') + 1);
}
foreach (string vp in Regex.Split(s, "&"))
{
string[] singlePair = Regex.Split(vp, "=");
if (singlePair.Length == 2)
{
nvc.Add(singlePair[0], singlePair[1]);
}
else
{
// only one key with no value specified in query string
nvc.Add(singlePair[0], string.Empty);
}
}
return nvc;
}
I needed a function that is a little more versatile than what was provided already when working with OLSC queries.
Here is my solution:
Public Shared Function ParseQueryString(ByVal uri As Uri) As System.Collections.Specialized.NameValueCollection
Dim result = New System.Collections.Specialized.NameValueCollection(4)
Dim query = uri.Query
If Not String.IsNullOrEmpty(query) Then
Dim pairs = query.Substring(1).Split("&"c)
For Each pair In pairs
Dim parts = pair.Split({"="c}, 2)
Dim name = System.Uri.UnescapeDataString(parts(0))
Dim value = If(parts.Length = 1, String.Empty,
System.Uri.UnescapeDataString(parts(1)))
result.Add(name, value)
Next
End If
Return result
End Function
It may not be a bad idea to tack <Extension()>
on that too to add the capability to Uri itself.
To do this without System.Web
, without writing it yourself, and without additional NuGet packages:
System.Net.Http.Formatting
using System.Net.Http;
Use this code:
new Uri(uri).ParseQueryString()
https://msdn.microsoft.com/en-us/library/system.net.http.uriextensions(v=vs.118).aspx
If you want to avoid the dependency on System.Web that is required to use HttpUtility.ParseQueryString, you could use the Uri
extension method ParseQueryString
found in System.Net.Http
.
Make sure to add a reference (if you haven't already) to System.Net.Http
in your project.
Note that you have to convert the response body to a valid Uri
so that ParseQueryString
(in System.Net.Http
)works.
string body = "value1=randomvalue1&value2=randomValue2";
// "http://localhost/query?" is added to the string "body" in order to create a valid Uri.
string urlBody = "http://localhost/query?" + body;
NameValueCollection coll = new Uri(urlBody).ParseQueryString();
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