I've had several cases where I had a page with several query parameters - most recently a search results page - and needed to create a link to the same page with one or more query parameters changed in the URL. This seems like such a common use case that I feel as though there must be some simple built-in way of doing it.
Right now, I'm using a function I wrote which takes in a dictionary of parameters and values and merges them with the params and values from Request.QueryString. Parameters given with a null value are removed. It works, but I'm open to simpler methods.
Minor improvements I'd suggest:
//...
{
UriBuilder ub = new UriBuilder(Request.Url);
//...
ub.Query = string.Join("&", parameters.Select(kv => string.Format("{0}={1}", Server.UrlEncode(kv.Key), Server.UrlEncode(kv.Value))));
return ub.ToString();
}
Edit
Actually the return value should also be a Uri type but I didn't want to introduce any breaking changes.
The function I'm using now:
public string ThisPageWithParams(IDictionary<string, string> newParameters)
{
string url = Request.Url.AbsolutePath + "?";
var parameters = new Dictionary<string, string>();
foreach (string k in Request.QueryString)
{
parameters[k] = Request.QueryString[k];
}
foreach (var kv in newParameters)
{
if (newParameters[kv.Key] == null)
{
parameters.Remove(kv.Key);
}
else
{
parameters[kv.Key] = kv.Value;
}
}
url += string.Join("&", parameters.Select(kv => Server.UrlEncode(kv.Key) + "=" + Server.UrlEncode(kv.Value)));
return url;
}
Related
Simple.OData.Client has a typed and dynamic (and basic) syntax.
I like the typed, but I don't want to build out all my types. In the end I really only need two or so types in the results I get.
But my queries need more types to properly filter the results.
So I want to use the dynamic syntax. But I want to cast the results to classes I have.
I can easily do this manually, but I thought I would see if Simple.OData.Client supports this before I go writing up all that conversion code for each query.
Here is some dynamic syntax code that runs without errors:
client.For(x.Client).Top(10).Select(x.ClientId, x.Name).FindEntriesAsync();
Here is an example of what I had hoped would work (selecting into a new Client object)
client.For(x.Client).Top(10).Select(new Client(x.ClientId, x.Name)).FindEntriesAsync();
But that kind of projection is not supported (I get an "has some invalid arguments" error).
Is there a way to support projection into an existing class when using the dynamic syntax of Simple.OData.Client?
EDIT: The code below works. But it's performance is terrible. I decided to abandon it and write hand written mappers for each type I needed.
This is what I came up with:
dynamic results = oDataClient.For(x.Client).Select(x.ClientId, x.Name).FindEntriesAsync().Result;
var listOfClients = SimpleODataToList<Client>(results);
public List<T> SimpleODataToList<T>(dynamic sourceObjects) where T : new()
{
List<T> targetList = new List<T>();
foreach (var sourceObject in sourceObjects)
{
// This is a dictionary with keys (properties) and values. But no
// matter what sourceObject is passed in, the values will always be
// the values of the first entry in the sourceObjects list.
var sourceProperties = ((System.Collections.Generic.IDictionary<string, object>)sourceObject);
var targetProperties = typeof(Client).GetProperties().Where(prop => prop.CanWrite);
var targetObject = new T();
foreach (var targetProperty in targetProperties)
{
if (sourceProperties.ContainsKey(targetProperty.Name))
{
var sourceValue = GetProperty(sourceObject, targetProperty.Name);
targetProperty.SetValue(targetObject, sourceValue, null);
}
}
targetList.Add(targetObject);
}
return targetList;
}
public static object GetProperty(object o, string member)
{
if (o == null) throw new ArgumentNullException("o");
if (member == null) throw new ArgumentNullException("member");
Type scope = o.GetType();
IDynamicMetaObjectProvider provider = o as IDynamicMetaObjectProvider;
if (provider != null)
{
ParameterExpression param = Expression.Parameter(typeof(object));
DynamicMetaObject mobj = provider.GetMetaObject(param);
GetMemberBinder binder = (GetMemberBinder)Microsoft.CSharp.RuntimeBinder.Binder.GetMember(0, member, scope, new CSharpArgumentInfo[] { CSharpArgumentInfo.Create(0, null) });
DynamicMetaObject ret = mobj.BindGetMember(binder);
BlockExpression final = Expression.Block(
Expression.Label(CallSiteBinder.UpdateLabel),
ret.Expression
);
LambdaExpression lambda = Expression.Lambda(final, param);
Delegate del = lambda.Compile();
return del.DynamicInvoke(o);
}
else
{
return o.GetType().GetProperty(member, BindingFlags.Public | BindingFlags.Instance).GetValue(o, null);
}
}
It was made much harder because normal casts and such for the dynamic objects returned would only give the first object in the list over and over. The GetProperty method works around this limitation.
I got a problem when debugging my MVC program and I want to acces to my db called "UserActivity".
on the browser, it saying that "The localhost page isn’t working
localhost redirected you too many times."
but without showing the specific error location.
here is my UserActivtyController, GET /UserActivity/Index code:
public class UserActivityController : BaseController
{
//GET /UserActivity/Index
public ActionResult Index(string returnUrl, int page = 1, string sort = "Id", string sortDir = "ASC", string filter = null)
{
String query = #"
SELECT Id
,CreatedBy
,CreatedOn
,ModifiedBy
,ModifiedOn
,ContactId
,EntityName
,EntityId
,ActivityType
,ActivityStatus
,DueDate
,ActualEndDate
,MasqueradeOn
,MasqueradeBy
FROM UserActivity
-- ORDER BY CreatedOn DESC
-- OFFSET (#PageNumber -1) * 30 ROWS
-- FETCH NEXT 30 ROWS ONLY
";
//string countQuery = #""
List<UserActivityModels> userActivity = null;
using (IDbConnection db = new MySqlConnection(ConfigurationManager.ConnectionStrings["CRMPORTALSQLCONN"].ConnectionString))
{
userActivity = (List<UserActivityModels>)db.Query<UserActivityModels>(query, new
{
#PageNumber = page,
});
/*ViewData["TotalCount"] = (int)db.ExecuteScalar(countQuery, new
{
#PageNumber = page,
#Id = string.IsNullOrEmpty(filter) ? null : filter
});
*/
ViewData["PageSize"] = 30;
ViewData["Filter"] = filter;
}
if (userActivity != null)
{
return RedirectToAction(returnUrl);
}
return View(userActivity);
}
}
Really appreciate if there anyone who know something about this problem. Thanks
if (userActivity != null)
{
return RedirectToAction(returnUrl);
}
If the returnUrl points to the same action ("UserActivity/Index") it will create infinite redirect loop. If you want to redirect request to different action make sure you pass correct name.
You have a loop back situation. This is similar to endless while loop. To fix it change your code redirection implementation to redirect to an action method. Notice how I have changed the implementation below. This will fix the issue "localhost redirected you too many times". You can improve on it to support passing in parameters, etc suitable for your situation. Also take a look at RedirectToAction with support for additional parameters, if you want to pass parameters to the action method, this link will be useful.
public class UserActivityController : BaseController
{
//GET /UserActivity/Index
public ActionResult Index(int page = 1, string sort = "Id", string sortDir = "ASC", string filter = null)
{
// Your other implementation here. I have removed it for brevity.
if (userActivity != null)
{
return RedirectToAction("Index");
}
return View(userActivity);
}
public ActionResult Index()
{
return View();
}
}
I don't know what is the value of redirectUrl but I suppose it to be null. I also suppose that your userActivity is not null. So return RedirectToAction(returnUrl); gets called.
When you call RedirectToAction(null) you actually redirect to the same action and everything repeats again.
I also am wondering why would you need to return View(userActivity); when your userActivity is null. I suppose you have a logical error.
I have different plugins in my Web api project with their own XML docs, and have one centralized Help page, but the problem is that Web Api's default Help Page only supports single documentation file
new XmlDocumentationProvider(HttpContext.Current.Server.MapPath("~/App_Data/Documentation.xml"))
How is it possible to load config from different files? I wan to do sth like this:
new XmlDocumentationProvider("PluginsFolder/*.xml")
You can modify the installed XmlDocumentationProvider at Areas\HelpPage to do something like following:
Merge multiple Xml document files into a single one:
Example code(is missing some error checks and validation):
using System.Xml.Linq;
using System.Xml.XPath;
XDocument finalDoc = null;
foreach (string file in Directory.GetFiles(#"PluginsFolder", "*.xml"))
{
if(finalDoc == null)
{
finalDoc = XDocument.Load(File.OpenRead(file));
}
else
{
XDocument xdocAdditional = XDocument.Load(File.OpenRead(file));
finalDoc.Root.XPathSelectElement("/doc/members")
.Add(xdocAdditional.Root.XPathSelectElement("/doc/members").Elements());
}
}
// Supply the navigator that rest of the XmlDocumentationProvider code looks for
_documentNavigator = finalDoc.CreateNavigator();
Kirans solution works very well. I ended up using his approach but by creating a copy of XmlDocumentationProvider, called MultiXmlDocumentationProvider, with an altered constructor:
public MultiXmlDocumentationProvider(string xmlDocFilesPath)
{
XDocument finalDoc = null;
foreach (string file in Directory.GetFiles(xmlDocFilesPath, "*.xml"))
{
using (var fileStream = File.OpenRead(file))
{
if (finalDoc == null)
{
finalDoc = XDocument.Load(fileStream);
}
else
{
XDocument xdocAdditional = XDocument.Load(fileStream);
finalDoc.Root.XPathSelectElement("/doc/members")
.Add(xdocAdditional.Root.XPathSelectElement("/doc/members").Elements());
}
}
}
// Supply the navigator that rest of the XmlDocumentationProvider code looks for
_documentNavigator = finalDoc.CreateNavigator();
}
I register the new provider from HelpPageConfig.cs:
config.SetDocumentationProvider(new MultiXmlDocumentationProvider(HttpContext.Current.Server.MapPath("~/App_Data/")));
Creating a new class and leaving the original one unchanged may be more convenient when upgrading etc...
Rather than create a separate class along the lines of XmlMultiDocumentationProvider, I just added a constructor to the existing XmlDocumentationProvider. Instead of taking a folder name, this takes a list of strings so you can still specify exactly which files you want to include (if there are other xml files in the directory that the Documentation XML are in, it might get hairy). Here's my new constructor:
public XmlDocumentationProvider(IEnumerable<string> documentPaths)
{
if (documentPaths.IsNullOrEmpty())
{
throw new ArgumentNullException(nameof(documentPaths));
}
XDocument fullDocument = null;
foreach (var documentPath in documentPaths)
{
if (documentPath == null)
{
throw new ArgumentNullException(nameof(documentPath));
}
if (fullDocument == null)
{
using (var stream = File.OpenRead(documentPath))
{
fullDocument = XDocument.Load(stream);
}
}
else
{
using (var stream = File.OpenRead(documentPath))
{
var additionalDocument = XDocument.Load(stream);
fullDocument?.Root?.XPathSelectElement("/doc/members").Add(additionalDocument?.Root?.XPathSelectElement("/doc/members").Elements());
}
}
}
_documentNavigator = fullDocument?.CreateNavigator();
}
The HelpPageConfig.cs looks like this. (Yes, it can be fewer lines, but I don't have a line limit so I like splitting it up.)
var xmlPaths = new[]
{
HttpContext.Current.Server.MapPath("~/bin/Path.To.FirstNamespace.XML"),
HttpContext.Current.Server.MapPath("~/bin/Path.To.OtherNamespace.XML")
};
var documentationProvider = new XmlDocumentationProvider(xmlPaths);
config.SetDocumentationProvider(documentationProvider);
I agree with gurra777 that creating a new class is a safer upgrade path. I started with that solution but it involves a fair amount of copy/pasta, which could easily get out of date after a few package updates.
Instead, I am keeping a collection of XmlDocumentationProvider children. For each of the implementation methods, I'm calling into the children to grab the first non-empty result.
public class MultiXmlDocumentationProvider : IDocumentationProvider, IModelDocumentationProvider
{
private IList<XmlDocumentationProvider> _documentationProviders;
public MultiXmlDocumentationProvider(string xmlDocFilesPath)
{
_documentationProviders = new List<XmlDocumentationProvider>();
foreach (string file in Directory.GetFiles(xmlDocFilesPath, "*.xml"))
{
_documentationProviders.Add(new XmlDocumentationProvider(file));
}
}
public string GetDocumentation(System.Reflection.MemberInfo member)
{
return _documentationProviders
.Select(x => x.GetDocumentation(member))
.FirstOrDefault(x => !string.IsNullOrWhiteSpace(x));
}
//and so on...
The HelpPageConfig registration is the same as in gurra777's answer,
config.SetDocumentationProvider(new MultiXmlDocumentationProvider(HttpContext.Current.Server.MapPath("~/App_Data/")));
I have a table named Orders that has a column named OrderCode that stores a string that I randomly generate at the time of creation.
I want to make sure this string (OrderCode) is unique before I save it to my table.
How I have attempted to do this:
bool isUnique = false;
var order = new Order();
var code = RandomCode.Generate();
while (isUnique == false) // checks to see if the code we generated is unique among all generated codes, if not, will generate another code
{
var activeOrders = storeDB.Orders.Find("OrderCode", code);
if (activeOrders == null)
{
isUnique = true;
}
else
{
code = RandomCode.Generate();
}
}
order.OrderCode = code;
The problem appears to be that the DbSet<TEntity>.Find Method is actually used to search through primary keys - but I am needing to search for a string that is not a primary key.
What is a correct approach to this situation?
if (context.Orders.Any(o => o.OrderCode == code))
{
// key found
}
if (context.Orders.FirstOrDefault(o => o.OrderCode == code) != null)
{
// key found
}
May I ask why you don't just use a System.Guid though (Guid.NewGuid().ToString())? This would virtually eliminate this kind of issue.
I know i can do this
var nv = HttpUtility.ParseQueryString(req.RawUrl);
But is there a way to convert this back to a url?
var newUrl = HttpUtility.Something("/page", nv);
Simply calling ToString() on the NameValueCollection will return the name value pairs in a name1=value1&name2=value2 querystring ready format. Note that NameValueCollection types don't actually support this and it's misleading to suggest this, but the behavior works here due to the internal type that's actually returned, as explained below.
Thanks to #mjwills for pointing out that the HttpUtility.ParseQueryString method actually returns an internal HttpValueCollection object rather than a regular NameValueCollection (despite the documentation specifying NameValueCollection). The HttpValueCollection automatically encodes the querystring when using ToString(), so there's no need to write a routine that loops through the collection and uses the UrlEncode method. The desired result is already returned.
With the result in hand, you can then append it to the URL and redirect:
var nameValues = HttpUtility.ParseQueryString(Request.QueryString.ToString());
string url = Request.Url.AbsolutePath + "?" + nameValues.ToString();
Response.Redirect(url);
Currently the only way to use a HttpValueCollection is by using the ParseQueryString method shown above (other than reflection, of course). It looks like this won't change since the Connect issue requesting this class be made public has been closed with a status of "won't fix."
As an aside, you can call the Add, Set, and Remove methods on nameValues to modify any of the querystring items before appending it. If you're interested in that see my response to another question.
string q = String.Join("&",
nvc.AllKeys.Select(a => a + "=" + HttpUtility.UrlEncode(nvc[a])));
Make an extension method that uses a couple of loops. I prefer this solution because it's readable (no linq), doesn't require System.Web.HttpUtility, and it supports duplicate keys.
public static string ToQueryString(this NameValueCollection nvc)
{
if (nvc == null) return string.Empty;
StringBuilder sb = new StringBuilder();
foreach (string key in nvc.Keys)
{
if (string.IsNullOrWhiteSpace(key)) continue;
string[] values = nvc.GetValues(key);
if (values == null) continue;
foreach (string value in values)
{
sb.Append(sb.Length == 0 ? "?" : "&");
sb.AppendFormat("{0}={1}", Uri.EscapeDataString(key), Uri.EscapeDataString(value));
}
}
return sb.ToString();
}
Example
var queryParams = new NameValueCollection()
{
{ "order_id", "0000" },
{ "item_id", "1111" },
{ "item_id", "2222" },
{ null, "skip entry with null key" },
{ "needs escaping", "special chars ? = &" },
{ "skip entry with null value", null }
};
Console.WriteLine(queryParams.ToQueryString());
Output
?order_id=0000&item_id=1111&item_id=2222&needs%20escaping=special%20chars%20%3F%20%3D%20%26
This should work without too much code:
NameValueCollection nameValues = HttpUtility.ParseQueryString(String.Empty);
nameValues.Add(Request.QueryString);
// modify nameValues if desired
var newUrl = "/page?" + nameValues;
The idea is to use HttpUtility.ParseQueryString to generate an empty collection of type HttpValueCollection. This class is a subclass of NameValueCollection that is marked as internal so that your code cannot easily create an instance of it.
The nice thing about HttpValueCollection is that the ToString method takes care of the encoding for you. By leveraging the NameValueCollection.Add(NameValueCollection) method, you can add the existing query string parameters to your newly created object without having to first convert the Request.QueryString collection into a url-encoded string, then parsing it back into a collection.
This technique can be exposed as an extension method as well:
public static string ToQueryString(this NameValueCollection nameValueCollection)
{
NameValueCollection httpValueCollection = HttpUtility.ParseQueryString(String.Empty);
httpValueCollection.Add(nameValueCollection);
return httpValueCollection.ToString();
}
Actually, you should encode the key too, not just value.
string q = String.Join("&",
nvc.AllKeys.Select(a => $"{HttpUtility.UrlEncode(a)}={HttpUtility.UrlEncode(nvc[a])}"));
Because a NameValueCollection can have multiple values for the same key, if you are concerned with the format of the querystring (since it will be returned as comma-separated values rather than "array notation") you may consider the following.
Example
var nvc = new NameValueCollection();
nvc.Add("key1", "val1");
nvc.Add("key2", "val2");
nvc.Add("empty", null);
nvc.Add("key2", "val2b");
Turn into: key1=val1&key2[]=val2&empty&key2[]=val2b rather than key1=val1&key2=val2,val2b&empty.
Code
string qs = string.Join("&",
// "loop" the keys
nvc.AllKeys.SelectMany(k => {
// "loop" the values
var values = nvc.GetValues(k);
if(values == null) return new[]{ k };
return nvc.GetValues(k).Select( (v,i) =>
// 'gracefully' handle formatting
// when there's 1 or more values
string.Format(
values.Length > 1
// pick your array format: k[i]=v or k[]=v, etc
? "{0}[]={1}"
: "{0}={1}"
, k, HttpUtility.UrlEncode(v), i)
);
})
);
or if you don't like Linq so much...
string qs = nvc.ToQueryString(); // using...
public static class UrlExtensions {
public static string ToQueryString(this NameValueCollection nvc) {
return string.Join("&", nvc.GetUrlList());
}
public static IEnumerable<string> GetUrlList(this NameValueCollection nvc) {
foreach(var k in nvc.AllKeys) {
var values = nvc.GetValues(k);
if(values == null) { yield return k; continue; }
for(int i = 0; i < values.Length; i++) {
yield return
// 'gracefully' handle formatting
// when there's 1 or more values
string.Format(
values.Length > 1
// pick your array format: k[i]=v or k[]=v, etc
? "{0}[]={1}"
: "{0}={1}"
, k, HttpUtility.UrlEncode(values[i]), i);
}
}
}
}
As has been pointed out in comments already, with the exception of this answer most of the other answers address the scenario (Request.QueryString is an HttpValueCollection, "not" a NameValueCollection) rather than the literal question.
Update: addressed null value issue from comment.
The short answer is to use .ToString() on the NameValueCollection and combine it with the original url.
However, I'd like to point out a few things:
You cant use HttpUtility.ParseQueryString on Request.RawUrl. The ParseQueryString() method is looking for a value like this: ?var=value&var2=value2.
If you want to get a NameValueCollection of the QueryString parameters just use Request.QueryString().
var nv = Request.QueryString;
To rebuild the URL just use nv.ToString().
string url = String.Format("{0}?{1}", Request.Path, nv.ToString());
If you are trying to parse a url string instead of using the Request object use Uri and the HttpUtility.ParseQueryString method.
Uri uri = new Uri("<THE URL>");
var nv = HttpUtility.ParseQueryString(uri.Query);
string url = String.Format("{0}?{1}", uri.AbsolutePath, nv.ToString());
I always use UriBuilder to convert an url with a querystring back to a valid and properly encoded url.
var url = "http://my-link.com?foo=bar";
var uriBuilder = new UriBuilder(url);
var query = HttpUtility.ParseQueryString(uriBuilder.Query);
query.Add("yep", "foo&bar");
uriBuilder.Query = query.ToString();
var result = uriBuilder.ToString();
// http://my-link.com:80/?foo=bar&yep=foo%26bar
In AspNet Core 2.0 you can use QueryHelpers AddQueryString method.
As #Atchitutchuk suggested, you can use QueryHelpers.AddQueryString in ASP.NET Core:
public string FormatParameters(NameValueCollection parameters)
{
var queryString = "";
foreach (var key in parameters.AllKeys)
{
foreach (var value in parameters.GetValues(key))
{
queryString = QueryHelpers.AddQueryString(queryString, key, value);
}
};
return queryString.TrimStart('?');
}
This did the trick for me:
public ActionResult SetLanguage(string language = "fr_FR")
{
Request.UrlReferrer.TryReadQueryAs(out RouteValueDictionary parameters);
parameters["language"] = language;
return RedirectToAction("Index", parameters);
}
You can use.
var ur = new Uri("/page",UriKind.Relative);
if this nv is of type string you can append to the uri first parameter.
Like
var ur2 = new Uri("/page?"+nv.ToString(),UriKind.Relative);