Is there a way to have action links which are relative to the current view.
For example, lets say I have a partial view which is a contains a paged list of news articles called _ArticlesList. I want to include this in the Admin and Index views, which are controlled by their relative controllers. _ArticlesList produces URLs which have the routeValues pageNumber and pageSize, but you have to hard code the controller, don't you?
I think what I want to do is just override properties in the routeValue object?
Edit:
I guess I could use HttpContext.Current.Request.RequestContext.RouteData.Values["controller"].ToString()
but that looks pretty bad
If you want to upload in For EX. Index file then write following to implement in your cshtml.
<div>
#Html.Partial("_ArticleList", Model)
</div>
You can put this in any div tag.
I used this to achieve what I wanted
public static class UrlHelperExtensions
{
public static string RelativeAction(this UrlHelper url, object routeValues)
{
var routeDataValues = url.RequestContext.RouteData.Values;
var queryString = url.RequestContext.HttpContext.Request.QueryString;
foreach (string key in queryString.Keys)
{
routeDataValues[key] = queryString[key];
}
// Allow routeValue object to take precedence over queryString
foreach (var prop in new RouteValueDictionary(routeValues))
{
routeDataValues[prop.Key] = prop.Value;
}
return url.RouteUrl(routeDataValues);
}
}
Related
How does the ASP.NET MVC's ViewBag work? MSDN says it is just an Object, which intrigues me, how does "Magic" properties such as ViewBag.Foo and magic strings ViewBag["Hello"] actually work?
Also, how can I make one and use it in my ASP.NET WebForms app?
Examples would be really appreciated!
ViewBag is of type dynamic but, is internally an System.Dynamic.ExpandoObject()
It is declared like this:
dynamic ViewBag = new System.Dynamic.ExpandoObject();
which is why you can do :
ViewBag.Foo = "Bar";
A Sample Expander Object Code:
public class ExpanderObject : DynamicObject, IDynamicMetaObjectProvider
{
public Dictionary<string, object> objectDictionary;
public ExpanderObject()
{
objectDictionary = new Dictionary<string, object>();
}
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
object val;
if (objectDictionary.TryGetValue(binder.Name, out val))
{
result = val;
return true;
}
result = null;
return false;
}
public override bool TrySetMember(SetMemberBinder binder, object value)
{
try
{
objectDictionary[binder.Name] = value;
return true;
}
catch (Exception ex)
{
return false;
}
}
}
It's a dynamic object, meaning you can add properties to it in the controller, and read them later in the view, because you are essentially creating the object as you do, a feature of the dynamic type. See this MSDN article on dynamics. See this article on it's usage in relation to MVC.
If you wanted to use this for web forms, add a dynamic property to a base page class like so:
public class BasePage : Page
{
public dynamic ViewBagProperty
{
get;
set;
}
}
Have all of your pages inherit from this. You should be able to, in your ASP.NET markup, do:
<%= ViewBagProperty.X %>
That should work. If not, there are ways to work around it.
The ViewBag is an System.Dynamic.ExpandoObject as suggested. The properties in the ViewBag are essentially KeyValue pairs, where you access the value by the key. In this sense these are equivalent:
ViewBag.Foo = "Bar";
ViewBag["Foo"] = "Bar";
ViewBag is used to pass data from Controller Action to view to render the data that being passed. Now you can pass data using between Controller Action and View either by using ViewBag or ViewData.
ViewBag: It is type of Dynamic object, that means you can add new fields to viewbag dynamically and access these fields in the View. You need to initialize the object of viewbag at the time of creating new fields.
e.g:
1. Creating ViewBag:
ViewBag.FirstName="John";
Accessing View:
#ViewBag.FirstName.
ViewBag is of type dynamic. More, you cannot do ViewBag["Foo"]. You will get exception - Cannot apply indexing with [] to an expression of type 'System.Dynamic.DynamicObject'.
Internal implementation of ViewBag actually stores Foo into ViewData["Foo"] (type of ViewDataDictionary), so those 2 are interchangeable. ViewData["Foo"] and ViewBag.Foo.
And scope. ViewBag and ViewData are ment to pass data between Controller's Actions and View it renders.
ViewBag is a dynamic type that allow you to dynamically set or get values and allow you to add any number of additional fields without a strongly-typed class
They allow you to pass data from controller to view.
In controller......
public ActionResult Index()
{
ViewBag.victor = "My name is Victor";
return View();
}
In view
#foreach(string a in ViewBag.victor)
{
.........
}
What I have learnt is that both should have the save dynamic name property ie ViewBag.victor
public dynamic ViewBag
{
get
{
if (_viewBag == null)
{
_viewBag = new DynamicViewData(() => ViewData);
}
return _viewBag;
}
}
I need an implementation where I can get infinite parameters on my ASP.NET Controller. It will be better if I give you an example :
Let's assume that I will have following urls :
example.com/tag/poo/bar/poobar
example.com/tag/poo/bar/poobar/poo2/poo4
example.com/tag/poo/bar/poobar/poo89
As you can see, it will get infinite number of tags after example.com/tag/ and slash will be a delimiter here.
On the controller I would like to do this :
foreach(string item in paramaters) {
//this is one of the url paramaters
string poo = item;
}
Is there any known way to achieve this? How can I get reach the values from controller? With Dictionary<string, string> or List<string>?
NOTE :
The question is not well explained IMO but I tried my best to fit it.
in. Feel free to tweak it
Like this:
routes.MapRoute("Name", "tag/{*tags}", new { controller = ..., action = ... });
ActionResult MyAction(string tags) {
foreach(string tag in tags.Split("/")) {
...
}
}
The catch all will give you the raw string. If you want a more elegant way to handle the data, you could always use a custom route handler.
public class AllPathRouteHandler : MvcRouteHandler
{
private readonly string key;
public AllPathRouteHandler(string key)
{
this.key = key;
}
protected override IHttpHandler GetHttpHandler(RequestContext requestContext)
{
var allPaths = requestContext.RouteData.Values[key] as string;
if (!string.IsNullOrEmpty(allPaths))
{
requestContext.RouteData.Values[key] = allPaths.Split('/');
}
return base.GetHttpHandler(requestContext);
}
}
Register the route handler.
routes.Add(new Route("tag/{*tags}",
new RouteValueDictionary(
new
{
controller = "Tag",
action = "Index",
}),
new AllPathRouteHandler("tags")));
Get the tags as a array in the controller.
public ActionResult Index(string[] tags)
{
// do something with tags
return View();
}
That's called catch-all:
tag/{*tags}
Just in case anyone is coming to this with MVC in .NET 4.0, you need to be careful where you define your routes. I was happily going to global.asax and adding routes as suggested in these answers (and in other tutorials) and getting nowhere. My routes all just defaulted to {controller}/{action}/{id}. Adding further segments to the URL gave me a 404 error. Then I discovered the RouteConfig.cs file in the App_Start folder. It turns out this file is called by global.asax in the Application_Start() method. So, in .NET 4.0, make sure you add your custom routes there. This article covers it beautifully.
in asp .net core you can use * in routing
for example
[HTTPGet({*id})]
this code can multi parameter or when using send string with slash use them to get all parameters
I'm building a generic web application for two business groups. The logo/banner needs to be changed based on the querystring. For example, if the url is http://foo.com/test?bg=a it shows the logo for business group a and if the url is http://foo.com/test?bg=b it shows the logo for business group b. This is not a problem if I only had one action. But I have many actions.
I could check the query string on all actions but there must be a nice way to do it. I have an perception that I need to do something with the routing stuff but just don't know how. Can anyone please let me know how to do it?
You can write a Custom Routing Handler and use routing to extract the querystring as a parameter, and pass into RouteData where it can be accessed anywhere.
public class RouteWithQueryStringValueHandler : MvcRouteHandler
{
private readonly string key;
public RouteWithQueryStringValueHandler(string key)
: base()
{
this.key = key;
}
protected override IHttpHandler GetHttpHandler(RequestContext requestContext)
{
var request = requestContext.HttpContext.Request;
var qsValue = requestContext.HttpContext.Request[key];
var router = base.GetHttpHandler(requestContext);
requestContext.RouteData.DataTokens[key] = qsValue;
return router;
}
}
Register as follows:
routes.Add(new Route("{controller}/{action}/{id}",
new RouteValueDictionary(
new { controller = "Home",
action = "Index",
id = UrlParameter.Optional
}),
new RouteWithQueryStringValueHandler("bg")));
Get the logo for Routing data:
var logo = RouteData.DataTokens["bg"];
You could write a custom helper method which based on the query string parameter will append a given class name to some div. Then of course you would have different class definitions in your CSS file applying a background-image.
For example:
public static class HtmlExtensions
{
public static string BannerClass(this HtmlHelper html)
{
var bg = html.ViewContext.Controller.ValueProvider.GetValue("bg");
if (bg == null || string.IsNullOrEmpty(bg.AttemptedValue))
{
// no bg parameter => return a default class
return "default_banner";
}
if (string.Equals("a", bg.AttemptedValue))
{
return "banner_a";
}
else if (string.Equals("b", bg.AttemptedValue))
{
return "banner_b";
}
// unknown value for the bg parameter => return a default class
return "default_banner";
}
}
and then in your _Layout you could apply this class to some placeholder like a div or even the body:
<div class="#Html.BannerClass()">OK</div>
This way it will always be applied for all view in your application.
Now all that's left is to define your CSS rules for the different banners:
.default_banner {
background-image: url('../images/default_banner.png')
}
.banner_a {
background-image: url('../images/banner_a.png')
}
.banner_b {
background-image: url('../images/banner_b.png')
}
If you are using Razor (and I believe this does break the separation of responsibilities guideline) change the _ViewStart.cshtml to do it.
#{
if (/* Context.QueryString Params, not at my development box*/)
{
Layout = "~/Views/Shared/Layout-Group1.cshtml";
}
else
{
Layout = "~/Views/Shared/Layout-Group2.cshtml";
}
}
I prefer this route because it makes any future requests (layout + css + javascript) fairly easy because they can all be updated within the Layout.
Place some code in your master page(s) to make the decision as to which banner to display based on the query string. Ideally the code wouldn't be completely inline i.e. it'd be in a helper class.
I have a number of permissions, and based on a set of conditions these permission determine if a user can see certain features. I have written a helper function for this as the logic in the view became quite extensive.
Essentially I'm looking for a function the same as Html.ActionLink that I can access from a class file (Ideally if I can access the Helper that would be great) So I can do somthing like so,
public static string GetAdminLinks()
{
if(PermCheck)
{
return(Html.ActionLink(...));
}
}
Any sugestions?
in controller:
Url.Action("Index", "Home", null, Request.Url.Scheme);
It largely depends on how your permission check is implemented (and of which information it needs to determine the user's permissions). Anyhow, I'd implement it as an extension to the HtmlHelper class.
Somewhere in your App_Code:
using System.Web.Mvc.Html;
public static class HtmlHelperExtensions {
public static string SecureActionLink(this HtmlHelper htmlHelper, string action, string controller){
if(PermCheck)
return htmlHelper.ActionLink(action, controller);
else
return string.Empty;
}
//add other ActionLink overrides if you like...
}
Then you'll be able to call the extension method from anywhere in your ViewPages without any code behind.
I'm looking for a best practice solution that aims to reduce the amount of URLs that are hard-coded in an ASP.NET application.
For example, when viewing a product details screen, performing an edit on these details, and then submitting the changes, the user is redirected back to the product listing screen. Instead of coding the following:
Response.Redirect("~/products/list.aspx?category=books");
I would like to have a solution in place that allows me to do something like this:
Pages.GotoProductList("books");
where Pages is a member of the common base class.
I'm just spit-balling here, and would love to hear any other way in which anyone has managed their application redirects.
EDIT
I ended up creating the following solution: I already had a common base class, to which I added a Pages enum (thanks Mark), with each item having a System.ComponentModel.DescriptionAttribute attribute containing the page's URL:
public enum Pages
{
[Description("~/secure/default.aspx")]
Landing,
[Description("~/secure/modelling/default.aspx")]
ModellingHome,
[Description("~/secure/reports/default.aspx")]
ReportsHome,
[Description("~/error.aspx")]
Error
}
Then I created a few overloaded methods to handle different scenarios. I used reflection to get the URL of the page through it's Description attribute, and I pass query-string parameters as an anonymous type (also using reflection to add each property as a query-string parameter):
private string GetEnumDescription(Enum value)
{
Type type = value.GetType();
string name = Enum.GetName(type, value);
if (name != null)
{
FieldInfo field = type.GetField(name);
if (field != null)
{
DescriptionAttribute attr = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute)) as DescriptionAttribute;
if (attr != null)
return attr.Description;
}
}
return null;
}
protected string GetPageUrl(Enums.Pages target, object variables)
{
var sb = new StringBuilder();
sb.Append(UrlHelper.ResolveUrl(Helper.GetEnumDescription(target)));
if (variables != null)
{
sb.Append("?");
var properties = (variables.GetType()).GetProperties();
foreach (var property in properties)
sb.Append(string.Format("{0}={1}&", property.Name, property.GetValue(variables, null)));
}
return sb.ToString();
}
protected void GotoPage(Enums.Pages target, object variables, bool useTransfer)
{
if(useTransfer)
HttpContext.Current.Server.Transfer(GetPageUrl(target, variables));
else
HttpContext.Current.Response.Redirect(GetPageUrl(target, variables));
}
A typical call would then look like so:
GotoPage(Enums.Pages.Landing, new {id = 12, category = "books"});
Comments?
I'd suggest that you derive your own class ("MyPageClass") from the Page class and include this method there:
public class MyPageClass : Page
{
private const string productListPagePath = "~/products/list.aspx?category=";
protected void GotoProductList(string category)
{
Response.Redirect(productListPagePath + category);
}
}
Then, in your codebehind, make sure that your page derives from this class:
public partial class Default : MyPageClass
{
...
}
within that, you can redirect just by using:
GotoProductList("Books");
Now, this is a bit limited as is since you'll undoubtedly have a variety of other pages like the ProductList page. You could give each one of them its own method in your page class but this is kind of grody and not smoothly extensible.
I solve a problem kind of like this by keeping a db table with a page name/file name mapping in it (I'm calling external, dynamically added HTML files, not ASPX files so my needs are a bit different but I think the principles apply). Your call would then use either a string or, better yet, an enum to redirect:
protected void GoToPage(PageTypeEnum pgType, string category)
{
//Get the enum-to-page mapping from a table or a dictionary object stored in the Application space on startup
Response.Redirect(GetPageString(pgType) + category); // *something* like this
}
From your page your call would be: GoToPage(enumProductList, "Books");
The nice thing is that the call is to a function defined in an ancestor class (no need to pass around or create manager objects) and the path is pretty obvious (intellisense will limit your ranges if you use an enum).
Good luck!
You have a wealth of options availible, and they all start with creating a mapping dictionary, whereas you can reference a keyword to a hard URL. Whether you chose to store it in a configuration file or database lookup table, your options are endless.
You have a huge number of options available here. Database table or XML file are probably the most commonly used examples.
// Please note i have not included any error handling code.
public class RoutingHelper
{
private NameValueCollecton routes;
private void LoadRoutes()
{
//Get your routes from db or config file
routes = /* what ever your source is*/
}
public void RedirectToSection(string section)
{
if(routes == null) LoadRoutes();
Response.Redirect(routes[section]);
}
}
This is just sample code, and it can be implemented any way you wish. The main question you need to think about is where you want to store the mappings. A simple xml file could do it:
`<mappings>
<map name="Books" value="/products.aspx/section=books"/>
...
</mappings>`
and then just load that into your routes collection.
public class BasePage : Page
{
public virtual string GetVirtualUrl()
{
throw new NotImplementedException();
}
public void PageRedirect<T>() where T : BasePage, new()
{
T page = new T();
Response.Redirect(page.GetVirtualUrl());
}
}
public partial class SomePage1 : BasePage
{
protected void Page_Load()
{
// Redirect to SomePage2.aspx
PageRedirect<SomePage2>();
}
}
public partial class SomePage2 : BasePage
{
public override string GetVirtualUrl()
{
return "~/Folder/SomePage2.aspx";
}
}