I have my global.asax setup with the following Session_Start:
protected void Session_Start()
{
HttpContext.Current.Session.Add("sourceCode", "default");
}
On my controller I have the following:
public ActionResult Index(string sourceCode)
{
if (sourceCode != null && sourceCode != "default")
{
Session["sourceCode"] = sourceCode;
return View();
}
else
{
return View();
}
}
I want to be able to display different partial layouts based on this session variable. What is the proper way to do this? Can I load a partial view from the controller or do I need to handle that on the view?
This is a variable that I want to use site wide to determine special pricing and landing page creatives. Do I have to set this same structure up on every single controller or is there a more global way of doing this?
Thanks,
Brian
If you want to show the layout in all the pages, you might want to add the logic in the layout file. There, you will add something like that (assuming razor)
#if(HttpContext.Current.Session["someValue"]){
#*render some partial*#
}else{
#*render some other partial*#
}
By the convention of MVC, controller should decide which view it should open. For this in controller you have code like this:
public ActionResult Index(string sourceCode)
{
if (sourceCode != null && sourceCode != "default")
{
Session["sourceCode"] = sourceCode;
ViewData["PartialView"] = "partialviewname1";
}
else
{
ViewData["PartialView"] = "partialviewname2";
}
return View();
}
and in view you can write code something like this:
<div>
#Html.Partial(Convert.ToString(ViewData["PartialView"]))
</div>
and if you have decide which partial view you have to load on each and every request then you can write above logic in global action filter. Global action filter get executed before any requested action method. To know more about global action filter you can explore this link.
http://www.asp.net/mvc/tutorials/older-versions/controllers-and-routing/understanding-action-filters-cs
Related
I have a MVC method that currently returns an ActionResult - I have had to make some changes and based on the business logic I want to do a response.redirect instead.
So I want to do something like this:
public ActionResult Index(CountryHomePageType currentPage)
{
if (someVar = true)
{
return View();
}
else
{
Response.redirect("www.website.com")
}
}
but I can't becuase Resonse.Redirect is not a ActionResult....
How can I get round this?
If you are redirecting outside of your current mvc application you can use
return Redirect("<your external url>"); // like "https://www.google.com"
if you want to redirecto back you your homepage you can use
return RedirectToAction("Index", "Home");
assuming you are using the default mvc setup
You might want to also look at ActionFilters if you are making this check in multiple places.
Can I return a view in PartialViewResult() like the following?:
public PartialViewResult EditAdminProfile_Post(int Id, FormCollection formCollection)
{
//if (Session["AdminID"] != null)
//{
Admin admin = new Admin();
admin = db.Admins.Single(m => m.ID == Id);
admin.Name = formCollection[0];
admin.Gender = formCollection[1];
admin.Email = formCollection[2];
admin.ContactNumber = formCollection[3];
admin.AboutMe = formCollection[4];
if (ModelState.IsValid)
{
db.Entry(admin).State = System.Data.Entity.EntityState.Modified;
db.SaveChanges();
}
return PartialView("AdminProfile");
AdminProfile is not a partial view.
Yes you can. It's not advised though, since your _layout is ignored (which means css or script files defined in the layout, so your styles and functionality may behave differently as you'd expect). Even though you can make it work, you're looking at code smell.
Are you looking to reuse AdminProfile as both a partial and normal view?
Create a partial view AdminProfilePartial with reusable content.
In your AdminProfile view, call AdminProfilePartial inside it (even if that's all you use)
Then when you return the full view:
return View("AdminProfile");
Otherwise partial view:
return PartialView("AdminProfilePartial");
The problem is that you don't pass the model to you partial view, that's why when you call it you get a Null reference
Update your code with this line:
return PartialView("AdminProfile", admin);
PS Instead of using FormCollection it's better to use default model binder and accept the Admin model in your action method
In ASP.NET MVC 5, does every Controller Action have to return a View with the same name as the Controller?
Here's my project. Have a webpage which contains a button to upload an image to a database. When the webpage is loaded, I want it to display a list of all the images that have already been uploaded. So, the Index (default) Action for this Controller loads the images from the database, and returns the Index View, which in turn displays the list of images:
public ActionResult Index()
{
// Load the images from the database
var images = GetImages();
return View(images);
}
On that same webpage, there is a button which allows the user to upload an image to the database. That button calls the Upload Action, which uploads the file based upon the "file" and "folder" arguments that are passed, and then finally returns the Index View again:
[HttpPost]
public ActionResult Upload(HttpPostedFileBase file, string folder)
{
// Upload the file from the specified folder
// ...
// ...
// ...
return Index();
}
However, when a user clicks on this upload button, the following error message is displayed:
The view 'Upload' or its master was not found or no view engine supports the searched locations
But I am not trying to render a View called "Upload" - I am trying to render the view called "Index", which is why I have the line return Index();.
Any help on where I'm going wrong?
Answer
Although Vitaliy and Nathan A provided adequate answers, I wanted to explain why your initial approach doesn't work because it's a great question and doesn't seem to make sense.
To get our answer we have to look at the ASP.NET MVC source code.
Before we get to that let's walk through your code.
The user visits (or POSTS to) /Controller/Upload
We do some logic and then return Index()
Index() is a method that returns its own view with its own model
MVC fails to find 'Upload' view and throws an exception
What went wrong?
Firstly know that Index() is being called and returned successfully. The model object is also being passed to the view (if one is found).
When you return Index(), it is returning View() which is an inherited method from the Controller class which returns a ViewResult.
A ViewResult inherits from ViewResultBase.
When a ViewResult is being returned it calls ExecuteResult().
Taking a look at the source code for ExecuteResult():
public override void ExecuteResult(ControllerContext context)
{
if (context == null)
{
throw new ArgumentNullException("context");
}
if (string.IsNullOrEmpty(this.ViewName))
{
this.ViewName = context.RouteData.GetRequiredString("action");
}
ViewEngineResult viewEngineResult = null;
if (this.View == null)
{
viewEngineResult = this.FindView(context);
this.View = viewEngineResult.View;
}
TextWriter output = context.HttpContext.Response.Output;
ViewContext viewContext = new ViewContext(context, this.View, this.ViewData, this.TempData, output);
this.View.Render(viewContext, output);
if (viewEngineResult != null)
{
viewEngineResult.ViewEngine.ReleaseView(context, this.View);
}
}
The key here is context.RouteData.GetRequiredString("action"). This code gets the action name so that a view can be found and rendered. Note that it is using a ControllerContext.
Because of this, your action is actually set when the Upload() method is first called. If you step through your Index() method you will see that calling context.RouteData.GetRequiredString("action") will return the string "Upload".
This is because, within the context of the user request, the action is in fact Upload (that's the page they requested).
Fun fact
If you return Index() and that method happens to alter the ViewBag (ViewData) then the ViewData will be altered regardless of what is rendered.
If your Upload() does this:
ViewBag.Test = "Upload method";
And you return Index() and your Index() does this:
ViewBag.Test = "Index method";
Then the value of Test will be "Index method".
Look up the documentation on the View method. It has several arguments you can provide, one of them being a string of the name of the view, but you always use the View() method if you want to return a view.
However, if you don't want to use the default View name (being the name of the action method), simply use a string to specify a new name like so:
public ActionResult Upload(HttpPostedFileBase file, string folder)
{
return View("Index");
}
you can do either:
return RedirectToAction("Index");
or:
return View("Index");
Just a side-note, you're not constrained to show views from the View folder for the controller name. You can do
public ActionResult something()
{
return View("../OtherView/somethingElse");
}
Is it possible to recognize the view/page name from which a form was submitted to Action ?
For example, lets say I have two Views: AddInfo and EditInfo
Both views have a form that I would like to submit to
#Html.BeginForm("SaveInfo","Info")
{
...
}
Inside of the SaveInfo() method I would like to recognize whether the submit/request came from AddInfo or EditInfo view.
public ActionResult SaveInfo(FormCollection collection)
{
if(...I got here from AddInfo View) <----- ?
{
..do something
}
}
Is it possible ?
Thanks
If the Add/Edit forms are at different pages on your site, then you can use Request.UrlReferrer to check where it came from. That is, something like:
bool sourceIsAddForm =
(Request.UrlReferrer.AbsoluteUri.IndexOf("/add", StringComparison.CurrentCultureIgnoreCase) != -1);
This question pertains primarily to good design.
Suppose I have a controller action like DeletePage that can be invoked in two separate views of the same controller. Assuming the delete logic is not contained in the action itself, but rather some conditional checks and the like that call the correct business logic, it doesn't make sense to duplicate the structure of the delete action when I can instead have a private method that returns an ActionResult which I call in both actions which can cause a delete. My question is where is the best place to place a reusable action method like this? Right now I'm just marking them private and sticking them in a region of the controller class, but perhaps an sealed inner class would make more sense for such a method- or somewhere else entirely.
Thoughts?
public ActionResult EditPage(int id, FormCollection formCollection)
{
var page = _pagesRepository.GetPage(id);
if (page == null)
return View("NotFound");
if (page.IsProtected)
return View("IllegalOperation");
if (formCollection["btnSave"] != null)
{
//...
}
else if (formCollection["btnDelete"] != null)
{
return DeletePage(page);
}
return RedirectToAction("Index");
}
public ActionResult DeletePage(int id)
{
var page = _pagesRepository.GetPage(id);
if (page == null)
return View("NotFound");
return DeletePage(page);
}
// Reusable Action
private RedirectToRouteResult DeletePage(Page page)
{
if(page != null && !page.IsProtected)
{
_pagesRepository.Delete(page);
_pagesRepository.Save();
FlashMessage(string.Format(PageForms.PageDeleted, page.Name), MessageType.Success);
return RedirectToAction("Index");
}
return RedirectToAction("Index");
}
I don't see why you need to make your reusable method an action method. Why not just a private method that returns void/bool/etc indicating the result of the save, and let your public action method return the RedirectToAction()? Effectively it's the same result, but I think it's a clearer approach.
public ActionResult DeletePage(int id)
{
var page = _pagesRepository.GetPage(id);
if (page == null)
return View("NotFound");
DeletePage(page);
return RedirectToAction("Index");
}
//reusable method
private void DeletePage(Page page)
{
//your same validation/save logic here
}
In the future you might consider moving this private DeletePage method into a separate service class that performs the validation and/or saving. Returning an an ActionResult would definitely not make sense in that case, so I think this example would be a more appropriate approach for your scenario.
In my opinion, your reusable code is an Action because it is returning an ActionResult. So your use is fine. The DeletePage(Page page) could potentially remain public.
I look forward to other opinions.
Personally I agree with Kurt. The concept of Deleting an unprotected page should be decoupled from what action the controller should perform. Secondly it's confusing from the code what should happen when the page is protected. In one action it redirects to the index, in the second it redirects to the "IllegalOperation" view. Personally I'd do something a little like...
public ActionResult DeletePage(int id) {
var page = _pagesRepository.GetPage(id);
if (!PageIsValidForDeletion(page)) {
string invalidPageView = FindViewForInvalidPage(page);
return View(invalidPageView);
}
DeletePage(page);
return RedirectToAction("Index");
}