Here's the situation: i have a SearchPage where an user can make a complex search. Nothing really unusual. After the results are displayed, the user can select one of them and move to another Page (Like a Master/Detail).
I have a breacrumb which holds the places where the user has been and it can have more than 4 levels (Like Main -> 2Page -> 3Page -> 4Page -> NPage). What i want is to maintain the state of each control on my complex search page, if the user uses the breacrumb to navigate backwards, since i don't want them to manually set all those search filters again.
So far, i've been using javascript:history.back(), but since i can have multiple levels on my breadcrumb, this hasn't been very useful. I was thinking about using OutputCache to do it, but i don't know how i would proceed.
UPDATE
I've just talked to a co-worker and he told me that some of our combobox (dropdownlist) are dynamically generated. So if the user select one item on the first combobox, the second will be filled with data related to the first selection.
OutputCache would cache the results for every user. Why don't you try to store the information in a cookie with page url and filter information. Each time an action is executed, read the cookie and populate the model (custom model for search) with those values found (if they match the page url, action in this situation). Pass the model to the view and let it repopulate the search criteria text boxes and check boxes.
UPDATE:
When a user fills in the search filter text boxes, you are passing that information back to a controller somehow. Probably as some kind of a strongly typed object.
Let's say your users get to enter the following information:
- Criteria
- StartDate
- EndDate
There is a model called SearchCriteria defined as:
public class SearchCriteria
{
public string Criteria { get; set; }
public DateTime? StartDate { get; set; }
public DateTime? EndDate { get; set; }
}
Your action could look something like this:
[HttpGet]
public ViewResult Search()
{
SearchCriteria criteria = new SearchCriteria();
if (Request.Cookies["SearchCriteria"] != null)
{
HttpCookie cookie = Request.Cookies["SearchCriteria"];
criteria.Criteria = cookie.Values["Criteria"];
criteria.StartDate = cookie.Values["StartDate"] ?? null;
criteria.EndDate = cookie.Values["EndDate"] ?? null;
}
return View(criteria);
}
[HttpPost]
public ActionResult Search(SearchCriteria criteria)
{
// At this point save the data into cookie
HttpCookie cookie;
if (Request.Cookies["SearchCriteria"] != null)
{
cookie = Request.Cookies["SearchCriteria"];
cookie.Values.Clear();
}
else
{
cookie = new HttpCookie("SearchCriteria");
}
cookie.Values.Add("Criteria", criteria.Criteria);
if (criteria.StartDate.HasValue)
{
cookie.Values.Add("StartDate", criteria.StartDate.Value.ToString("yyyy-mm-dd"));
}
if (criteria.EndDate.HasValue)
{
cookie.Values.Add("EndDate", criteria.EndDate.Value.ToString("yyyy-mm-dd"));
}
// Do something with the criteria that user posted
return View();
}
This is some kind of a solution. Please understand that I did not test this and I wrote it from top of my head. It is meant to give you an idea just how you might solve this problem. You should probably also add Action to SearchCriteria so that you can check whether this is an appropriate action where you would read the cookie. Also, reading and writing a cookie should be moved into a separate method so that you can read it from other actions.
Hope this helps,
Huske
Related
I posted the question earlier, but didn't receive any correct responses, hence posting again with some edits. I have a function that accepts two parameters, IDs and Dates. When I had put breakpoints, I was able to see the Ids and the Dates selected on the page as parameter values. However, after hitting the process button, nothing happens, meaning this data isn't getting saved to the DB.
Model Classes:
public class Hello{
public string ID{ get; set; }
[DataType(DataType.Date)]
[DisplayFormat(DataFormatString = "{0:yyyy-MM-dd}", ApplyFormatInEditMode = true)]
public DateTime? Date{ get; set; }
}
Controller Class:
[HttpGet]
public ActionResult Selection(string ids, string dates)
{
model = new Hello();
ExtensionDB db = new ExtensionDB();
string[] IDS = ids.Split(',');
string[] DATES = dates.Split(',');
List<Hello> list = new List<Hello>();
for (int i = 0; i < IDS.Length; i++)
{
if (IDS[i] != null && IDS[i] != "")
{
Hello item = new Hello { ID = IDS[i], Date = DateTime.Parse(DATES[i]) };
list.Add(item);
}
}
if (ModelState.IsValid)
{
foreach (var row in db.Table1)
{
foreach (var row2 in db.Table2)
{
if (row.UID== row2.CID) // UID and CID are Foreign keys that join these two tables
{
foreach (var item in list)
{
if (row.UID == Convert.ToInt32(item.ID))
{
row2.ReportedDate = item.Date;
}
db.SaveChanges();
}
}
}
}
ViewBag.Message = "Success";
return View(model);
}
else
{
ViewBag.Message = "Failed";
return View(model);
}
}
I will add the view class if needed, however the problem is here.. You can also refer to it here: Saving changes to the DB MVC
Your code does not attempt to update anything. Start with confirming what the data you are passing to this POST call contains, and what you want to do with it. It looks like what you are trying to do is update the dates for a number of records. Looking at your previous post (no need to re-post another question with the same code) there are a few things..
First: Structure the data you want to pass to the POST call into a collection of simple objects containing an id and a date. For example:
{
id = rid,
date = date
}
and add those to the collection named something like "updateData" rather than two separate arrays of IDs and dates. Then in the server-side code, declare a simple view model class:
public class UpdateDateViewModel
{
public int Id { get; set; }
public DateTime Date { get; set; }
}
In the ajax call instead of:
data: { ids: ids, dates: dates },
you'll want something like:
data: { updates: updateData },
where updateData is your collection of id + date pairs.
and use that view model in your method:
public ActionResult Process(IList updates)
Provided that request data is sent as Json, ASP.Net should translate that data automatically for you, though you may need to configure ASP.Net to translate the camelCase vs PascalCase. Worst case, to test, you can use camelCase property names ("id" and "date")
Now when it comes to updating the data: Server side, please get in the habit of using meaningful variable names, not "c", "i", etc. It makes code a lot easier to understand.
public ActionResult Process(IList<UpdateDateViewModel> updates)
{
using (db = new DB())
{
//rp = new RequestProcess(); - Assuming RequestProcess is an Entity?
//var c = rp.getStuff(); - No idea what this getStuff() method does...
foreach(var update in updates)
{
var request = db.RequestProcesses.Find(update.Id);
if (request != null)
request.RequestDate = update.Date; // If we find a matching request, update it's date.
else
{ // Doesn't exist, create it and add it to the DbSet.(table)
var request = new RequestProcess { Id = update.Id, RequestDate = update.Date };
db.RequestProcesses.Add(request);
}
db.SaveChanges();
}
}
}
Now this is a very bare bones guess at what you may be trying to do. Ideally though, updates should be completely separate from adds in the sense that an update should only deal with existing records. If it comes across an ID that it cannot find it should throw an error, ignore, and/or return a status to the user that something wasn't right. Creating new entries should be a separate call and ensure that records are properly initialized with their required fields.
Your original code looked to be taking a list of IDs, but then creating a new entity and calling that "getStuff" method that didn't have the DbContext, or any of the values from the POST call, but then attempting to copy values from that entity into the string parameters that you passed (which would overwrite the Json string) None of that would have updated an entity which would never have updated your data.
Take it slow and follow the examples before attempting to adapt them to your ideas. It will be a lot more constructive and less frustrating then writing a bunch of code that doesn't really make much sense, then wondering why it doesn't work. Your original code has probably a dozen or more problems and inefficiencies. Simply pasting it up on Stack will get a lot of confusing comments based on these problems which don't really help with the first issue you want to solve. Strip it back to the minimum, start with getting the data you need to the server in a meaningful way, then from that, attempt to use that data to update your entities.
When i call my admin controller- Index Action method will get all the user details
when i want select particular user again i dont want to hit the DB.
both action method same controller and i'm using model popup for display details.
My Question
I dont want to use entity framework.
- when admin form load i will get all the user details this is Index Action Method
-based on user id i need to display particular user so again i dont want hit to the DB already i'm having all the user details. that details how to get another action method?
i can remember asp.net i used session to share the data globally. like that asp.net mvc is possible? please help me.
Thanks
It looks you're looking for a cache mechanism. For simple scenarios, I use a simple static variable, but I keep it in a separated class. Let's suppose you have a User class like this:
public class User
{
public string Id { get; set; }
public string Name { get; set; }
}
You could create a class like this:
public static class UserCacheService
{
private static IEnumerable<User> _users;
private static readonly object lockObj = new object();
public static IEnumerable<User> GetUsers()
{
lock (lockObj)
{
if (_users == null)
{
using (var db = new MyNiceDbContext())
{
_users = db.Users.ToList();
}
}
return _users;
}
}
public static void InvalidateCache()
{
lock (lockObj)
{
_users = null;
}
}
}
Then you can get your shared users in any action, of any controller like this:
public class AdminController : Controller
{
public ActionResult Index()
{
// the first time, it'll need to get users from DB (e.g with Entity Framework)
var users = UserCacheService.GetUsers();
return View();
}
}
The first time, the _users in your UserCacheService will be null, and as expected, it'll need to load users from database. However, the next time it won't, no matter if you are using another controller:
public class AnotherController : Controller
{
public ActionResult Index(string userId)
{
// now, it won't load from DB anymore, because _users is already populated...
var users = UserCacheService.GetUsers();
var currentUser = users.Where(u => u.Id == userId).FirstOrDefault();
if (currentUser != null)
{
// do something with the user...
}
return View();
}
}
There are times when unfortunately your _users will become null again, for example when you restart your ApplicationPool in IIS, but UserCacheService is already prepared for fetching database once if that's the case.
Be careful about three things:
Whenever you keep data in memory (like _users), you are consuming
your server's memory, which might be limited. Don't start trying to
keep everything in memory, only data you know you'll need everytime.
Whenever you update something in your users, like a name, an address or something else, since the _users will not get from database everytime, you need to call the UserCacheService.InvalidateCache() method, in order to force the next call to load again from database, thus making sure you have _users up to date.
This only works for simplistic scenarios. If you have your application distributed in two or more servers, this won't work, as each server has it's own memory and they can't share it out of the box. That's when you would look forward for something like Redis. Though, I don't think it's your case here.
I am building a service which requires a somewhat lengthy setup process. I have it broken into 4 models and 4 corresponding views. They are Setup, Setup2, Setup3, and Setup4. Each of these views gathers information from the user which is stored in a User object. I have been passing the user along like this:
[HttpPost]
public ActionResult Setup(FormCollection values)
{
User registeringUser = new User();
registeringUser.email = User.Identity.Name;
registeringUser.fName = values["fName"];
registeringUser.lName = values["lName"];
registeringUser.phone = values["phone"];
return RedirectToAction("/Setup2", registeringUser);
}
For some reason, this seems to work just fine for the first jump (from Setup to Setup2) but after that I'm getting weird behavior, such as User. getting set to null when the User is passed to another View.
In a related, but slightly different issue, I need the last screen (Setup4) to be recursive. This screen adds a course in which the user is enrolled, and if they don't check the "This was my last class" button, it needs to basically clear the form so they can enter another course.
The entire Controller looks like this:
[HttpPost]
public ActionResult Setup4(FormCollection values, User registeringUser)
{
// values["allClassesAdded"] returns "false" as a string if box is unchecked, returns "true,false" if checked.
// Solution: parse string for "true"
if (utils.parseForTrue(values["allClassesAdded"]))
{
// TODO Redirect to "congratulations you're done" page.
database.CreateUserInDB(registeringUser);
return Redirect("/Home");
}
else
{
// Build course and add it to the list in the User
course c = new course(values);
if (Request.IsAuthenticated)
{
//registeringUser.currentCourses.Add(c);
registeringUser.AddCourse(c);
return RedirectToAction("/Setup4", registeringUser); // <---- This doesn't really work right
//return View();
}
else
{
return Redirect("/Account/Login");
}
}
}
This is my first project with MVC, so if you find that I'm doing the entire thing completely incorrectly, feel free to not answer the question I asked and offer the proper solution to this need. I'm moving an existing (pure) C# project to MVC and I'm mainly just stuck on how to work within MVC's interesting structure. I'm very grateful for any help you can give!
Thanks!
You can store user related data in session without passing it between requests
Smth like this
[HttpPost]
public ActionResult Step1(Step1Model model)
{
Session["UserRegistration"] = new UserRegistration
{
FirstName = model.fName,
....
}
....
}
[HttpPost]
public ActionResult Step2(Step2Model model)
{
var userRegistration = Session["UserRegistration"] as UserRegistration;
if (userRegistration == null) { return Redirrect("Step1"); }
userRegistration.SomeField = model.someField;
...
Session["UserRegistration"] = userRegistration;
....
}
I am working on asp.net mvc3 web application using MS Sql server 2008 express rc2. In my app I have two different brands in DB and one of them have few Null or 'unknown' values (e.g. 'unknown' is added to DB instead of Null). My question is how to pass only non null values to View Engine instead of using If/Else statements in View?
in controller:
var model = _data.GetViewModel(query);
if (model != null)
{
return View(model);
}
else
return View("Error");
in ViewModel;
public int Id { get; set; }
public string Query { get; set; }
public string Brand { get; set; }
public string Family { get; set; }
public string Type { get; set; }
in Model:
public ViewModel GetViewModel(string query)
{
var data = _comp.Get(p => p.Query == query);
if (data == null) return null;
return new ViewModel
{
Id = data.id,
Brand = data.brand,
Family = data.family,
Type = data.type
};
}
in View (I am currently using If statement):
#if (Model.Brand != null)
{
<span class="brand">#Model.Brand</span>
}
#if (Model.Family != null)
{
<span class="family">#Model.Family</span>
}
#if (Model.Type != null)
{
<span class="type">#Model.Type</span>
}
Note: I want to avoid If statement because there are too many values in the Database of each brand, and many of the them are Null, So I don't want to generate Html for those Null values. I am using If/Else statement like above code, and for checking too many values in View using If, it costs Memory on server and processor, and it also slow down server response time.
I want to have an alternative method to do this. Should I use Partial views or anything else?
Please Please help me to solve this, Your help is very appreciated.
Thanks and Regards.
First, some background/context, then my suggestion.
(By the way, this all applies to any version of ASP.NET MVC or ASP.NET NancyFX (yes, there's another option out there!!), etc)
Context / Background
To solve this, people generally fall into two types of categories:
Just get data and let the View decide what to show (common one, not the proper way IMO).
The Controller should handle all the heavy lifting and give the view the exact answer (proper way, IMO).
The first way is quick and dirty. Sure it works, but it puts too much logic into the view. Views are not supposed to do any logic at all (exception: for loops, and maybe the odd if/else, maybe). The main reason for this is testing. Yep, that dirty word which people hate and think it's for hippies only. Or .. I don't have the time to test.. so I manually test, etc.. If you put any business logic into a view, you cannot test that.
The second way might seem a bit slower at first, but that's like anything - the more you practice, the faster you go. This is (IMO) the preferred method of doing things because you can test the controller. The controller should create a view model which will have -the exact- results that the view needs. Not extra. For example, imagine you want to return a list of Brands to the display/view. Most people do (the equivalent of) Get-all-brands into a list, and send that list to the view, even though 80% of those properties are -not- going to be used by that view! Even if ONE property is not going to be used by that view, do not retrieve it nor send it to the view!
So - TL;DR; do all the heavy lifting in the controller. The View is dumb. Just dump the exact view model data, to the view.
Solution to your problem
Ok, so let's roll with idea #2 and get all this stuff happening in the controller.
// Grab the results.
// ASSUMPTION: It is only returning the -exact- data I need. No more, no less.
var results = _data.GetViewModel(query);
if (model == null)
{
// Project the results into a perfectly tight & svelte view model
// 100% specific for this view.
var viewModel = results.
Select(x => new ViewModel
{
Id = x.Id,
Brand = string.IsNullOrEmpty(x.Brand)
? string.Empty
: x.Brand,
Family = string.IsNullOrEmpty(x.Family)
? string.Empty
: x.Family,
Type = string.IsNullOrEmpty(x.Type)
? string.Empty
: x.Type,
}).ToList();
return viewModel;
Testing this..
[Fact]
public void GivenSomeBrands_Index_ReturnsAViewModel()
{
// Arrange.
// NOTE: Our fake repostitory has some fake data. In it ..
// Id: 1, Brand: Gucci.
// Id: 22, Brand: null.
var controller = new BrandController(SomeFakeRepositoryThingy);
// Act.
var result = controller.Index(); // This calls that controller code, above.
// Assert.
Assert.IsNotNull(result); // Controller returned some result.
Assert.IsNotNull(result.Model); // We have some model data.
var model = result.Model as IList<ViewModel>(); // Cast the Model value.
Assert.NotNull(model); // We have a strongly typed view model.
// We check the first brand value.
Assert.Equal("Gucci", model.First().Brand);
// We know this item has a null Brand,
Assert.Equal(string.Empty, model[21].Brand); but the ViewModel converted it.
}
You could write a custom HTML helper:
public static string MyHelper<V>(this HtmlHelper helper, V value, string css)
{
if (value == null)
return "";
return String.Format("<span class='{0}'>{1}</span>", value, css);
}
Then in your view:
#Html.MyHelper(Model.Brand, "brand");
#Html.MyHelper(Model.Family, "family");
#Html.MyHelper(Model.Type, "type");
I am trying to use session state in MVC and I have been stuck for the entire evening!
I realise session state should be used sparingly in MVC - but I am sure I want to use it for this one page - so would appreciate solutions rather than opinions.
Basically, I have a contact form with a CAPTCHA image. When the page loads I want to set the session to the characters used in the CAPTCH image (dynamically generated image).
I have an 'new image' link which async creates a new code, sets the session and dynamically loads a new image to screen.
The session stays sets as long as the page doesn't load or reload. I need to be able to validate the user input against the code in session (which should reflect what is displayed to the user) but the session is empty.
If I perform an AJAX reload on the image i.e. set the session asynchronously - the session is set when I perform a post!!
What's going on?
I need to be able to persist the session value - arrrhhhh!
I have this is a base controller:
public new HttpContextBase HttpContext
{
get
{
HttpContextWrapper context = new HttpContextWrapper(System.Web.HttpContext.Current);
return (HttpContextBase)context;
}
}
and in the controller I have:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Contact(ContactForm c, string button)
{
string sessCaptcha = HttpContext.Session["CAPTCHA_Contact"] == null ? "" : HttpContext.Session["CAPTCHA_Contact"].ToString();
}
Any ideas????? pretty pls with a cherry on top :)
Thanks!
I am so embarrased right now...
Never ever set a session value before a Response.End() (and i believe also the same applies to response.redirect).
OMG - that's 4 hours I will never ever get back again!
Here is the demo code to illustrate my ineptitude...
public ActionResult Page1()
{
Session["test1"] = "hello world";
// This means the session won't be set
// It's is used in valid circumstances..e.g. setting session, then dynamically generating an image based on that value.
Response.End();
return View();
}
public ActionResult Page2()
{
ViewBag.Test = Session["test1"].ToString();
return View();
}
[HttpPost]
public ActionResult Page2(FormCollection fc)
{
ViewBag.Test = "...is still..." + Session["test1"].ToString();
return View();
}
You may want to look into using the TempData object
http://blog.donnfelker.com/2010/02/26/aspnet-mvc2-tempdata-now-persists/