Binding parameter to complex type - asp.net-mvc

I have a navigation bar, with several links, like this:
MenuItem1
This request would hit my action method:
public ActionResult Browse(int departmentId)
{
var complexVM = MyCache.GetComplexVM(departmentId);
return View(complexVM);
}
This is my ComplexVM:
public class ComplexVM
{
public int DepartmentId { get; set; }
public string DepartmentName { get; set; }
}
MyCache, is a static list of departments, which I am keeping in memory, so when user passes in DepartmentId, I wouldn't need to get the corresponding DepartmentName from DB.
This is working fine... but it would be nice if I could somehow initialize ComplexVM in custom model binder, instead of initializing it in the Controller... so I still want to use a link (menu item), but this time, a CustomModelBinder binds my parameter, 2, to ComplexVM: it needs to look up the name of department with id = 2 from MyCache and initialize ComplexVM, then ComplexVM would be passed to this action method:
public ActionResult Browse(ComplexVM complexVM)
{
return View(complexVM);
}
I want to hit the above controller without doing a post-back, as I have a lot of menu item links in my navigation bar... not sure if this is possible? Or if this is even a good idea?
I have seen this link, which sort of describes what I want... but I am not sure how the routing would work... i.e. routing id:2 => ComplexVM
Alternatively would it be possible to do this in RouteConfig, something like this:
routes.MapRoute(
name: "Browse",
url: "{controller}/Browse/{departmentId}",
// this does not compile, just want to explain what I want...
defaults: new { action = "Browse", new ComplexVM(departmentId) });

I can achieve this with little change and with one trick
MenuItem1
Controller action
public ActionResult Browse(ComplexVM complexVM)
{
return View(complexVM);
}
View model
public class ComplexVM
{
public int DepartmentId { get; set; }
public string DepartmentName { get; set; }
public ComplexVM()
{
this.DepartmentId = System.Convert.ToInt32(HttpContext.Current.Request("id").ToString);
this.DepartmentName = "Your name from cache"; // Get name from your cache
}
}
This is without using model binder. Trick may help.

That is possible. It is also a good idea :) Off-loading parts of the shared responsibility to models / action filters is great. The only problem is because they are using some special classes to inherit from, testing them sometimes might be slightly harder then just testing the controller. Once you get the hang of it - it's better.
Your complex model should look like
// Your model class
[ModelBinder(typeof(ComplexVMModelBinder)]
public class ComplexVMModel
{
[Required]
public int DepartmentId { get; set; }
public string DepartmentName { get; set; }
}
// Your binder class
public class ComplexVMModelBinder : IModelBinder
{
// Returns false if you can't bind.
public bool BindModel(HttpActionContext actionContext, ModelBindingContext modelContext)
{
if (modelContext.ModelType != typeof(ComplexVMModel))
{
return false;
}
// Somehow get the depid from the request - this might not work.
int depId = HttpContext.Current.Request.Params["DepID"];
// Create and assign the model.
bindingContext.Model = new ComplexVMModel() { DepartmentName = CacheLookup(), DepId = depId };
return true;
}
}
Then at the beginning of your action method, you check the ModelState to see if it's valid or not. There are a few things which can make the model state non-valid (like not having a [Required] parameter.)
public ActionResult Browse(ComplexVM complexVM)
{
if (!ModelState.IsValid)
{
//If not valid - return some error view.
}
}
Now you just need to register this Model Binder.
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
ModelBinders.Binders.Add(typeof(ComplexVMModel), new ComplexVMModelBinder());
}
Your should be able to use the route config that you've provided.

Related

How to omit/prevent data from being sent to the POST method in the Controller in MVC

I have a view that is using a model and I am using that information to create a form.
I have three steps of the form that are optional or may not be shown.
The problem is that these hidden sections get posted along with the form data and break the business logic. (I have no control over the business logic)
So is there a way to tell the framework not to pass certain sections or fields? Perhaps VIA a class or something?
I know I could use AJAX to send certain sections as they are needed, but the site spec is to have them hidden and displayed as needed.
Although you could do this client-side, it won't stop malicious over-posting/mass assignment.
I suggest reading 6 Ways To Avoid Mass Assignment in ASP.NET MVC.
Excerpts:
Specify Included Properties only:
[HttpPost]
public ViewResult Edit([Bind(Include = "FirstName")] User user)
{
// ...
}
Specify Excluded Properties only:
[HttpPost]
public ViewResult Edit([Bind(Exclude = "IsAdmin")] User user)
{
// ...
}
Use TryUpdateModel()
[HttpPost]
public ViewResult Edit()
{
var user = new User();
TryUpdateModel(user, includeProperties: new[] { "FirstName" });
// ...
}
Using an Interface
public interface IUserInputModel
{
string FirstName { get; set; }
}
public class User : IUserInputModel
{
public string FirstName { get; set; }
public bool IsAdmin { get; set; }
}
[HttpPost]
public ViewResult Edit()
{
var user = new User();
TryUpdateModel<IUserInputModel>(user);
// ...
}
Use the ReadOnlyAttribute
public class User
{
public string FirstName { get; set; }
[ReadOnly(true)]
public bool IsAdmin { get; set; }
}
Lastly, and the most recommended approach is to use a real ViewModel, instead a domain Model:
public class UserInputViewModel
{
public string FirstName { get; set; }
}
Show/Hide will not allow/disallow the value from being sent to the Controller.
Elements that are Disabled or just not editable will (99% of the time) be returned as null / minVal.
You can set the elements in the View as Disabled by using JQuery in the script:
$('#elementID').attr("disabled", true);
OR you could use a DOM command:
document.getElementById('elementID').disabled = "true";
So you can set the fields as both Disabled AND Hidden, so that it is neither displayed, nor populated. Then in your Controller you can just base the Business Logic on whether or not certain fields (preferable Mandatory fields, if you have any) are null.
You can check this in C# like this:
For a string:
if (string.IsNullOrWhiteSpace(Model.stringField))
{
ModelState.AddModelError("stringField", "This is an error.");
}
For a DateTime:
if (Model.dateTimeField == DateTime.MinValue)
{
ModelState.AddModelError("dateTimeField ", "This is an error.");
}
Just for interest sake, here is how you can Hide/Show elements on the View using JQuery:
$('#elementID').hide();
$('#elementID').show();

MVC 3 Edit Function not working

I can't seem to get the edit function of my view to work..i have a page that lists, a page that shows specific detail and on that page, i should be able to edit the information of the form..PROBLEM: when i run the application it says:No parameterless constructor defined for this object. What am i doing wrong...?
In the Home Controller i have:
Edit Functions:
[HttpGet]
public ViewResult EditSchoolDetails(int id)
{
var institution = _educationRepository.GetInstititionById(id);
var model = (Mapper.Map<Institution, InstitutionModel>(institution));
return View(model);
}
post
[HttpPost]
public ActionResult EditSchoolDetails( InstitutionModel institutionModel, int id)
{
if (ModelState.IsValid) {
//_get from repository and add to instituion
var institution = _educationRepository.GetInstititionById(institutionModel.Id);
// Map from the view model back to the domain model
var model = Mapper.Map<Institution, InstitutionModel>(institution);
//UpdateModel(model);
SaveChanges();
return RedirectToAction("ViewSchoolDetails", new {institutionModel = institutionModel, id = id});
}
return View(institutionModel);
}
InstitutionModel
public class InstitutionModel {
public InstitutionModel() {
NAABAccreditations = new List<AccreditationModel>();
}
public int Id { get; set; }
public string Name { get; set; }
public bool IsNAAB { get { return NAABAccreditations.Any(); } }
public string Website { get; set; }
public AddressModel Address { get; set; }
public IEnumerable<AccreditationModel> NAABAccreditations { get; set; }
}
Does the Institution class have a parameterless constructor? If not, that will be the problem. You are passing an InstitutionModel to the the edit view, so the post action should probably take an InstitutionModel too, then you can map back to the original Institution model:
public ActionResult EditSchoolDetails(int id, InstitutionModel institutionModel)
{
if (ModelState.IsValid)
{
//add to database and save changes
Institution institutionEntity = _educationRepository.GetInstititionById(institution.Id);
// Map from the view model back to the domain model
Mapper.Map<InstitutionModel, Institution>(institutionModel, institutionEntity);
SaveChanges();
return RedirectToAction("ViewSchoolDetails",);
}
return View(institutionModel);
}
Notice also how it returns the view model back to the view if the model state isn't valid, otherwise you will lose all your form values!
Here's a similar question too which might help: ASP.NET MVC: No parameterless constructor defined for this object
Is it possible you need to pass a parameter to ViewSchoolDetails? I notice in the return statement you commented out that you were passing it an id, but in the return statement you're using, you're not passing in anything.
EDIT
This (from your comment below):
parameters dictionary contains a null entry for parameter 'id' of non-nullable type 'System.Int32' for method 'System.Web.Mvc.ActionResult ViewSchoolDetails(Int32)
...tells me you need to pass a parameter to ViewSchoolDetails
EDIT 2
I saw your edit, and would say this: if the method you are calling is
public ActionResult ViewSchoolDetails(InstitutionModel institutionModel, int id)
Then you MUST pass it an object of type InstitutionModel and an int as parameters or you will get an exception. Meaning, you need
RedirectToAction("ViewSchoolDetails", new {institutionModel = institutionModel, id = id});
Whenever i get this, i have forgotten to create a parameter-less constructor on my view-model. I always add one now just in case it's needed and i forget.
Does InstitutionModel have one?

Minimal way to handle static content routes/controllers/views from data driven menus?

I have a ListItem class that is used to represent menu items in my application:
public class ListItem : Entity
{
public virtual List List { get; set; }
public virtual ListItem ParentItem { get; set; }
public virtual ICollection<ListItem> ChildItems { get; set; }
public int SortOrder { get; set; }
public string Text { get; set; }
public string Controller { get; set; }
public string Action { get; set; }
public string Area { get; set; }
public string Url { get; set; }
}
I use this data to construct the routes for the application, but I was wondering if there was a clean way to handle controller/views for static content? Basically any page that doesn't use any data but just views. Right now I have one controller called StaticContentController, which contains a unique action for each static page that returns the appropriate view like so:
public class StaticContentController : Controller
{
public ActionResult Books()
{
return View("~/Views/Books/Index.cshtml");
}
public ActionResult BookCategories()
{
return View("~/Views/Books/Categories.cshtml");
}
public ActionResult BookCategoriesSearch()
{
return View("~/Views/Books/Categories/Search.cshtml");
}
}
Is there some way I could minimize this so I don't have to have so many controllers/actions for static content? It seems like when creating my ListItem data I could set the Controller to a specific controller that handles static content, like I have done, but is there anyway to use one function to calculate what View to return? It seems like I still need separate actions otherwise I won't know what page the user was trying to get to.
The ListItem.Url contains the full URL path from the application root used in creating the route. The location of the View in the project would correspond to the URL location to keep the organization structure parallel.
Any suggestions? Thanks.
Edit: My Route registration looks like so:
public static void RegisterRoutes(RouteCollection routes)
{
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
routes.IgnoreRoute("Shared/{*pathInfo}");
routes.MapRoute("Access Denied", "AccessDenied", new { controller = "Shared", action = "AccessDenied", area = "" });
List<ListItem> listItems = EntityServiceFactory.GetService<ListItemService>().GetAllListItmes();
foreach (ListItem item in listItems.Where(item => item.Text != null && item.Url != null && item.Controller != null).OrderBy(x => x.Url))
{
RouteTable.Routes.MapRoute(item.Text + listItems.FindIndex(x => x == item), item.Url.StartsWith("/") ? item.Url.Remove(0, 1) : item.Url, new { controller = item.Controller, action = item.Action ?? "index" });
}
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
);
}
You can use a single Action with one parameter (the View name) which will return all the static pages
public class StaticContentController : Controller
{
public ActionResult Page(string viewName)
{
return View(viewName);
}
}
You will also need to create a custom route for serving these views, for example:
routes.MapRoute(
"StaticContent", // Route name
"page/{viewName}", // URL with parameters
new { controller = "StaticContent", action = "Page" } // Parameter defaults
);
I see in your example that you specify different folders for your views. This solution will force you to put all static views in the Views folder of the StaticContentController.
If you must have custom folder structure, then you can change the route to accept / by adding * to the {viewName} like this {*viewname}. Now you can use this route: /page/Books/Categories. In the viewName input parameter you will receive "Books/Categories" which you can then return it as you like: return View(string.Format("~/Views/{0}.cshtml", viewName));
UPDATE (Avoiding the page/ prefix)
The idea is to have a custom constraint to check whether or not a file exists. Every file that exists for a given URL will be treated as static page.
public class StaticPageConstraint : IRouteConstraint
{
public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
{
string viewPath = httpContext.Server.MapPath(string.Format("~/Views/{0}.cshtml", values[parameterName]));
return File.Exists(viewPath);
}
}
Update the route:
routes.MapRoute(
"StaticContent", // Route name
"{*viewName}", // URL with parameters
new { controller = "StaticContent", action = "Page" }, // Parameter defaults
new { viewName = new StaticPageConstraint() } // Custom route constraint
);
Update the action:
public ActionResult Page(string viewName)
{
return View(string.Format("~/Views/{0}.cshtml", viewName));
}

Multiple Submit Buttons in MVC3 - FormCollection has no Key/Value for Input Type Submit - Remote Validation Issue?

I have the two buttons in MVC3 application.
<input type="submit" name="command" value="Transactions" />
<input type="submit" name="command" value="All Transactions" />
When I click on a button, it posts back correctly but the FormCollection has no "command" keys. I also added a property "command" in the model and its value is null when the form is posted.
public ActionResult Index(FormCollection formCollection, SearchReportsModel searchReportsModel). {
if (searchReportsModel.command == "All Transactions")
...
else
....
}
I am using IE8. How can I use multiple buttons in MVC3? Is there a workaround for this issue? I did lot of research and could not find a solution.
Update:
Dave: I tried your solution and it is throwing Http 404 error "The resource cannot be found".
Here is my code:
[HttpPost]
[AcceptSubmitType(Name = "Command", Type = "Transactions")]
public ActionResult Index(SearchReportsModel searchReportsModel)
{
return RedirectToAction("Transactions", "Reports", new { ...});
}
[HttpPost]
[ActionName("Index")]
[AcceptSubmitType(Name = "Command", Type = "All Transactions")]
public ActionResult Index_All(SearchReportsModel searchReportsModel)
{
return RedirectToAction("AllTransactions", "Reports", new { ... });
}
public class AcceptSubmitTypeAttribute : ActionMethodSelectorAttribute
{
public string Name { get; set; }
public string Type { get; set; }
public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo)
{
return controllerContext.RequestContext.HttpContext
.Request.Form[this.Name] == this.Type;
}
}
The issue was resolved after commenting the following Remote validation attribute in the ViewModel (SearchReportsModel). It looks like it is a bug in MVC3:
//[Remote("CheckStudentNumber", "SearchReports", ErrorMessage = "No records exist for this Student Number")]
public int? StudentNumber { get; set; }
You might be able to get away with an ActionMethodSelectorAttribute attribute and override the IsValidForRequest method. You can see below this method just determines whether a particular parameter (Name) matches one of it's properties (Type). It should bind with a view model that looks like this:
public class TestViewModel
{
public string command { get; set; }
public string moreProperties { get; set; }
}
The attribute could look like this:
public class AcceptSubmitTypeAttribute : ActionMethodSelectorAttribute
{
public string Name { get; set; }
public string Type { get; set; }
public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo)
{
return controllerContext.RequestContext.HttpContext
.Request.Form[this.Name] == this.Type;
}
}
Then, you could tag your actions with the AcceptSubmitType attribute like this:
[AcceptSubmitType(Name="command", Type="Transactions")]
public ActionResult Index(TestViewModel vm)
{
// use view model to do whatever
}
// to pseudo-override the "Index" action
[ActionName("Index")]
[AcceptSubmitType(Name="command", Type="All Transactions")]
public ActionResult Index_All(TestViewModel vm)
{
// use view model to do whatever
}
This also eliminates the need for logic in a single controller action since it seems you genuinely need two separate courses of action.
Correct me If I'm wrong, but according to W3C standard you should have only 1 submit button per form. Also having two controls with identical names is a bad idea.
when you submit (on any button) your whole page is posted back to the controller action, I have had the same problem but have not found a decent solution yet.. maybe you could work with a javascript 'onclick' method and set a hidden value to 1 for the first button and 0 for the second button or something like that?
This is a nice Blog about this found here
I like the look of adding in AcceptParameterAttribute
#CodeRush: The W3C standard does allow more than 1 submit per form. http://www.w3.org/TR/html4/interact/forms.html. "A form may contain more than one submit button".

Too many params in URL - Routing ASP.NET MVC

Im searching the best way for manage long urls in routing. I have many actions which looks like this:
/a/b/c/d/e
the route:
routes.MapRoute(
"xxx",
"{a}/{b}/{c}/{d}/{e}",
new { controller = "Xxx", action="Xxx"});
the controller:
public ActionResult Xxx(int a, int b, int c, int d, int e) { ... }
any change in params gives multi-change in every route/action, and that is the problem. Its not elastic. Is there any possibility to map params to some object? Something that would look like:
public ActionResult Xxx(RouteParams rp) { ... }
Hmm... eventually I think that I could use the Action Filter to solve this:
private RouteParams rp;
public override void OnActionExecuting(FilterExecutingContext filterContext) {
rp = new RouteParams(...);
}
but I dont like this solution
Best regards
Create an object like you did and use ModelBinder to construct it instead of filter. The Default Model binder should work, if not then create a custom one.
Keep your route settings the same, just create a new model with properties matching the parameters in the route settings:
public class XxxModel
{
public int a { get; set; }
public int b { get; set; }
public int c { get; set; }
public int d { get; set; }
public int e { get; set; }
}
Then use XxxModel as your parameter in the action:
public ActionResult Xxx( XxxModel model )
{
...
}
a, b, c, d and e will be mapped to the properties in the model.
Will this work for you?
routes.MapRoute(
"xxx",
"{*params}",
new { controller = "Xxx", action="Xxx"});
and
public ActionResult Xxx(string params) { ... }
params will be one string (eg. 1/2/3/4/5)
you'll have to do a params.Split("/") and Convert.ToInt32() to the parameters.

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