I'm new to MVC and am a little caught up in how routing works. Currently, my route contains the subject name of a class, but I'd also like it to contain the professor ID.
how can I accomplish this if the subject name and the professor ID are from 2 different models?
So, for example, I'm currently routing the subject name by doing this:
#model List<CourseModel>
<h1>
#foreach (var course in Model)
{
<a asp-controller="Course" asp-action="Index" asp-route-SubjectName="#course.SubjectName"> #course.SubjectName </a>
<br />
}
</h1>
However, as I stated above, the professor ID I'd like to put in the routing is from another model (but I can only call one model in a view) so I feel a bit stuck.
The code I have above is the professor/details view, so I feel like it should be simple to pull data from the professor controller, but I must be mistaken. the variable in the Professor controller is called "ID" but I can't seem to access it in the view when trying to put the value of it in the routing link.
Any suggestions? I'd appreciate any at all
If you want to achieve this you should have a model like this, since you are in a details view of the professor, which teaches n courses.
public class ProfessorDetailsViewModel
{
/*
All the Professor Properties
*/
public int Id {get; set;}
public List<CourseViewModel> Courses {get; set}
}
and then you could use your razor view like this:
#model ProfessorDetailsViewModel
<h1>
#foreach (var course in Model.Courses)
{
<a asp-controller="Course" asp-action="Index" asp-route-SubjectName="#course.SubjectName" asp-route-ProfessorId="#Model.Id"> #course.SubjectName </a>
<br />
}
</h1>
Related
I have a small asp.net core mvc application that basically consists of a form that a user can input some constraints into, and then get a filtered list of data depending on those constraints.
The controller action for filtering data basically looks like this:
[HttpPost]
public async Task<IActionResult> Query(QueryModel query)
{
var customers = await _context.Customers.AsQueryable().FilterCustomerList(query);
return View("Index", customers);
}
Now, my issue is that I would like the inputs in the fields to persist after entering them and being redirected to the view again. Right now they are currently just reset.
One way of doing this that I found was using viewBag. An example for a single query attribute is this:
public async Task<IActionResult> Query(QueryModel query)
{
var customers = await _context.Customers.AsQueryable().FilterCustomerList(query);
ViewBag.Name = query.Name;
return View("Index", customers);
}
and then the inpuit html elelment would look like:
<div class="col-md-4">
<input name="Name" type="text" placeholder="First name" value="#ViewBag.Name"class="form-control">
</div>
And this makes sure that if something has been entered into a field, it will now be entered into the field when after the query has been submitted.
But when I read up on ViewBag, I understand that a lot of .net developers have an aversion to it. It's not safe, the compiler can't catch errors in it easily etc.
Also, If I were to add all the input fields in my form to the viewbag, I would need a lot of lines of ViewBag.Attribute = query.SomeAttribute (20-30). Which seems like a code-smell too.
Is there any nicer way to do what I am trying to here?
You haven't included your QueryModel class and that class could be a key point to a cleaner approach.
You see, usually the user data, POSTed to your action is bound to the model, from there it's rendered on the form and is POSTed again. The model binding is where an input of a specific name is bound to a model member of the same name.
Thus, there's no need for viewbags.
More formally:
The Model
public class QueryModel
{
[your-validators-in-attributes, e.g. Required or MaxLength
there can be multiple validators]
public string Name { get; set; }
}
The controller:
[HttpPost]
async Task<IActionResult> Query(QueryModel query)
{
// query.Name is there, bound from the view
}
The View:
#model .....QueryModel
<div>
#Html.TextBoxFor( m => m.Name, new { placeholder = "a placeholder" } )
</div>
The html helper does two things
renders an input of the given name (Name in this case)
sets its value depending on the actual value from the model
In newer ASP.NETs you can achieve similar result by using tag helpers, where instead of Html.TextBoxFor(...) you write
<input asp-for="Name" />
These two approaches, using html helpers or using tag helpers are equivalent. In both cases there's no need for view bags.
I viewed some topics here but I still have a problem with getting values from checkboxes.
Part of Model :
public Dictionary<Language, bool> TargetLanguages { get; set; }
Part of View :
<div class="editor-label">
<label for="TargetLanguages">select target languages</label>
</div>
<div class="editor-field">
<form>
#foreach (var item in Model.TargetLanguages)
{
#Html.CheckBox("TargetLanguages["+item.Key.Name+"]", item.Value)
#item.Key.Name
}
</form>
</div>
Part of Controller :
[HttpPost, ActionName("AddDictionary")]
public ActionResult AddDictionary(FormCollection collection)
{
...
}
And the problem is I don't get any trace of TargetLanguages in my FormCollection. I tried CheckBoxFor but it wasn't help. I tried write check-box manually also.
EDITED : Okay, I just noticed where the problem was. I've got messed up markers and that was the reason why I can't get data from FormCollection.
Create all the checkboxes with the same name. In this sample I'm using 'SelectedTargetLanguages'.
#using (Html.BeginForm())
{
foreach (var item in Model.TargetLanguages)
{
<label>
#Html.CheckBoxFor(m => m.SelectedTargetLanguages, item.value)
#item.KeyName
</label>
}
<br/>
#Html.SubmitButton("Actualizar listado")
}
Then, in your action the parameter must be an array of strings like this:
public ActionResult AddDictionary(string[] selectedTargetLanguages)
Note that the name of the argument is the same name of the checkboxes. (It works even with the different casing).
You should use explicit arguments like this, rather than the generic FormCollection. Anyway, if you use FormCollection, you shpuld also receive the array.
I have asked same type of question previously. Please check the following links
MVC3 #Html.RadioButtonfor Pass data from view to controller
MVC3 #html.radiobuttonfor
I think this might helps you.
I have a model class Person
public class Person
{
public string name { get; set; }
public string area { get; set; }
}
Now, in my Index view, I want to pass values from view to controller by taking value name property from user and area ="foo".I know how I can take values from user by like below
#using (Html.BeginForm())
{
#Html.Label("Name")
#Html.TextBoxFor(m=>m.name)
<input type="submit" value="Name" />
}
Now, I want area ="foo" in views.I tried to google the problem,I did not find the solution.
This is general problem.Do not answer like ,set value area="foo" in controller.
Please help me and don't downvote without commenting so that I can improve my question in future.
Thanks
Add a hidden field to your form with name "area" and set the value as whatever you want. When your form is posted, the hidden field value will be also posted to your action method.
#using (Html.BeginForm())
{
#Html.Label("Name")
#Html.TextBoxFor(m=>m.name)
<input type="hidden" name="area" value="foo" />
<input type="submit" value="Name" />
}
Now you can get this in your HttpPost action method
[HttpPost]
public ActionResult Create(Person model)
{
// check for model.name and model.area.
// TO DO : Save and redirect
}
You should remember that, people can always update the hidden field value in the browser using some tools like firebug or so. If it is a sensitive information (Price of an item in a shopping portal) , don't read like this from client. Read it from server.
I was reading http://www.orchardproject.net/docs/Creating-1-n-and-n-n-relations.ashx and could not get the idea, if it is possible to easily make master detail editing, to give you concrete example i've attached screenshot from wordpress:
So there is post and post contains set of custom fields, simple 1:N relationship, everything edited in one page - you can add/edit custom field without leaving post page.
May be someone saw similar example for Orchard on internet, or could shortly describe path to achieve this by code, would be really helpful (I hope not only for me, because this is quite common case I think).
This should be possible, although not in the most 'Orchardy' way.
I've not tested any of the below so it is probably full of mistakes - but maybe Bertrand or Pszmyd will be along later today to correct me :-)
As you have probably seen you can pass a view model to a view when creating a content shape in your editor driver:
protected override DriverResult Editor(CatPart part, dynamic shapeHelper)
{
// Driver for our cat editor
var viewModel = new CatViewModel
{
Cats = _catService.GetCats() // Cats is IEnumerable<Cat>
};
return ContentShape("Parts_CatPart_Edit",
() => shapeHelper.EditorTemplate(
TemplateName: "Parts/CatPart",
Model: viewModel,
Prefix: Prefix
));
}
So we can pass in a list of items, and render it in our view like so:
#foreach(var cat in Model.Cats)
{
<span class="cat">
<p>#cat.Name</p>
<a href="...">Delete Cat</p>
</span>
}
The problem here would be posting back changes to update the model. Orchard provides an override of the Editor method to handle the postback when a part is edited, and we can revive the viewmodel we passed in the previous method:
protected override DriverResult Editor(CatPart part, IUpdateModel updater, dynamic shapeHelper)
{
var viewModel = new CatViewModel();
if (updater.TryUpdateModel(viewModel, Prefix, null, null))
{
// Access stuff altered in the Cat view model, we can then update the CatPart with this info if needed.
}
}
This works really well for basic information like strings or integers. But I've never been able to get it working with (and not been sure if it is possible to do this with) dynamic lists which are edited on the client side.
One way around this would be to set up the buttons for the items on the N-end of the 1:N relationship such that they post back to an MVC controller. This controller can then update the model and redirect the client back to the editor they came from, showing the updated version of the record. This would require you to consistently set the HTML ID/Name property of elements you add on the client side so that they can be read when the POST request is made to your controller, or create seperate nested forms that submit directly to the contoller.
So your view might become:
#foreach(var cat in Model.Cats)
{
<form action="/My.Module/MyController/MyAction" method="POST">
<input type="hidden" name="cat-id" value="#cat.Id" />
<span class="cat">
<p>#cat.Name</p>
<input type="submit" name="delete" value="Delete Cat" />
</span>
</form>
}
<form action="/My.Module/MyController/AddItem" method="POST">
<input type="hidden" name="part-id" value="<relevant identifier>" />
<input type="submit" name="add" value="Add Cat" />
</form>
Another possibility would be to create a controller that can return the relevant data as XML/JSON and implement this all on the client side with Javascript.
You may need to do some hacking to get this to work on the editor for new records (think creating a content item vs. creating one) as the content item (and all it's parts) don't exist yet.
I hope this all makes sense, let me know if you have any questions :-)
I am trying to create a timesheet application in MVC 2, but I feel like I am still struggling to grasp the model/view relationships and all that.
The problem I have is, I want to let the user report a new time segment in a create view. But I want to have dropdownlists populated with Projects, Tasks, and Consultants from the model.
Basically the database structure looks like this:
(table) TimeSegments
TimeSegmentID
Hours
Date
ConsultantID (FK)
TaskID (FK)
ProjectID (FK)
(table) Projects
ProjectID
ProjectName
(table) Tasks
TaskID
TaskName
(table) Consultants
ConsultantID
ConsultantName
This design may be extended in future, right now I want to get basic functionality working before I complicate it further.
Now, I am passing the entire model to the create view (actually a viewmodel based on it, just to simplify some coding, but it might as well have been the entire model).
The problem is, normally when I have done similar things with a create view, I would have created a new object in the controller and passed that to the view. In this case it would have been the TimeSegment object, since it is a new time segment that should be created in the database. Then I could just submit it and update the database in the controller. However, if I only pass a new TimeSegment object to the view, I can't populate the dropdownlists with Projects, Tasks and Consultants.
And oppositely, if I only pass the entire model, how would I bind a textbox to a new TimeSegment to be updated in the database?
I feel like I need to send both a new TimeSegment object and the entire model to do this, but then I have no idea how I would access it (there's only that one "Model" to access from the view). Also, back in the controller after a submit, how would the controller know what to update?
I'm sure I'm just thoroughly confused still by the MVC way of thinking, but I would really appreciate it if someone could clarify this for me and tell me (as pedagogically as possible) what to do to solve this.
Okay, I will give it a shot.
MVC is not hard, but you do have to alter your way of thinking a bit. In MVC you have the Models (your data layer[s]), the Views and the Controllers.
Before we continue, I make the assumptions with my examples below that you are using LINQ to SQL for you data access layer (Model), and I have labeled it as dc.
The Controllers fetch and format the data out of the Models and hand it off to the Views to display. So lets start with your first view which would be the view to create a TimeSegment.
[HttpGet]
public ActionResult CreateTimeSegment() {
return View(new TimeSegmentView {
Consultants = dc.Consultants.ToList(),
Projects = dc.Projects.ToList(),
Tasks = dc.Tasks.ToList()
});
}
This action will create a TimeSegmentView object and pass that to the View as its Model. Keep in mind that this action is decorated with [HttpGet]. TimeSegmentView` is a container class for the objects you need to pass to the view to create your UI and it looks like this:
public class TimeSegmentView {
public IList<Consultant> Consultants { get; set; }
public IList<Project> Projects { get; set; }
public IList<Task> Tasks { get; set; }
public TimeSegment TimeSegment { get; set; }
}
NOTE: I'm not using the TimeSegment property yet, it's further down...
In the view make sure you have it inherit from TimeSegmentView. Assuming that you're following the default MVC project structure and with me taking the liberty to add a Views folder into the Models folder your full reference would look like this:
<%# Page Inherits="System.Web.Mvc.ViewPage<PROJECTNAME.Models.Views.TimeSegmentView>" %>
Now you've typed the view to that object and you can now interact with its properties. So, you can build a form such as:
<form action="/" method="post">
<p>
<label>Hours</label>
<input name="TimeSegment.Hours" />
</p>
<p>
<label>Date</label>
<input name="TimeSegment.Date" />
</p>
<p>
<label>Consultant</label>
<select name="TimeSegment.ConsultantID">
<% foreach (Consultant C in Model.Consultants) { %>
<option value="<%=C.ConsultantID%>"><%=C.ConsultantName%></option>
<% }; %>
</select>
</p>
<p>
<label>Project</label>
<select name="TimeSegment.ProjectID">
<% foreach (Project P in Model.Projects) { %>
<option value="<%=P.ProjectID%>"><%=P.ProjectName%></option>
<% }; %>
</select>
</p>
<p>
<label>Task</label>
<select name="TimeSegment.TaskID">
<% foreach (Task T in Model.Tasks) { %>
<option value="<%=T.TaskID%>"><%=T.TaskName%></option>
<% }; %>
</select>
</p>
</form>
As you can see it created 3 select fields and just performed loops in each of them to build up their values based off of the model.
Now, taking a submission of this form, we'll need to get the data and add it to our database with:
[HttpPost]
public RedirectToRouteResult CreateTimeSegment(
[Bind(Prefix = "TimeSegment", Include = "Hours,Date,ConsultantID,ProjectID,TaskID")] TimeSegment TimeSegment) {
dc.TimeSegments.InsertOnSubmit(TimeSegment);
dc.SubmitChanges();
return RedirectToAction("EditTimeSegment", new {
TimeSegmentID = TimeSegment.TimeSegmentID
});
}
Okay, first notice that I've named the action the same, but this one has an [HttpPost] decoration. I'm telling the action that I'm sending it a TimeSegment object and that I want it to bind the properties in the Include clause (this is mostly for security and validation). I then take the TimeSegment object I've passed in, add it to the data context, submit the changes and redirect. In this case I'm redirecting to another action to edit the object I just created passing in the new TimeSegmentID. You can redirect to what ever, this just felt appropriate to me...
[HttpGet]
public ActionResult EditTimeSegment(
int TimeSegmentID) {
return View(new TimeSegmentView {
Consultants = dc.Consultants.ToList(),
Projects = dc.Projects.ToList(),
Tasks = dc.Tasks.ToList(),
TimeSegment = dc.TimeSegments.Single(t => t.TimeSegmentID == TimeSegmentID)
});
}
In the edit action your doing the same thing as in the create action by building a new TimeSegmentView object and passing it to the view. The key difference here is that you're now populating the TimeSegment property. Your form would look something like this (shortened from above):
<form action="/<%=Model.TimeSegment.TimeSegmentID%>" method="post">
<p>
<label>Hours</label>
<input name="TimeSegment.Hours" value="<%=Model.TimeSegment.Hours%>" />
</p>
</form>
And your receiving action on the controller would look like this:
[HttpPost]
public RedirectToRouteResult EditTimeSegment(
int TimeSegmentID) {
TimeSegment TS = dc.TimeSegments.Single(t => t.TimeSegmentID == TimeSegmentID);
TryUpdateModel<TimeSegment>(TS, "TimeSegment", new string[5] {
"Hours", "Date", "ConsultantID", "ProjectID", "TaskID"
});
dc.SubmitChanges();
return RedirectToAction("EditTimeSegment", new {
TimeSegmentID = TimeSegment.TimeSegmentID
});
}
Lastly, if you want to display a list of TimeSegments you can do something like this:
[HttpGet]
public ActionResult ListTimeSegments() {
return View(new TimeSegmentsView {
TimeSegments = dc.TimeSegments.ToList()
});
}
And TimeSegmentsView looks like this:
public class TimeSegmentsView {
public IList<TimeSegment> TimeSegments { get; set; }
}
And in the View you'd want to do this:
<table>
<% foreach (TimeSegment TS in Model.TimeSegments) { %>
<tr>
<td><%=TS.Hours%></td>
<td><%=TS.Date%></td>
<td><%=TS.Project.ProjectName%></td>
<td><%=TS.Consultant.ConsultantName%></td>
<td><%=TS.Task.TaskName%></td>
</tr>
<% }; %>
</table>
I hope this is enough to give you a start. It's by no means complete, but its 5 AM and I haven't slept yet, so this will have to do for now (from me). Feel free to name your actions what you want, you don't have to stick to my naming conventions.
I would suggest however that you change the naming of the properties of your tables. For example when your writing the expressions like in the table above you'll have to do TS.Project.ProjectName and that's redundant. You're already accessing the Project property of TS through their relationship so you know you're only going to work with a Project. This then makes ProjectName a pointless blob of text re-describing the object your working with. Instead just use Name, and turn your expression to TS.Project.Name.
Anyway, just a suggestion, do what you like better. I'm passing out, so good night and happy Thanksgiving!
UPDATE
The process with collections is essentially the same as far as the controller side is conserned. It's the client side and the JavaScript that's more difficult to get going, so I'll assume that you have something established on that end.
So, here's how the controller would work. You pass in an array of TimeSegment and the model binder is smart enough to figure it out through the Prefix of your form elements.
<form action="/<%=Model.TimeSegment.TimeSegmentID%>" method="post">
<p>
<label>Hours</label>
<input name="TimeSegment[0].Hours" />
<!-- Notice the array in the prefix -->
</p>
<p>
<label>Hours</label>
<input name="TimeSegment[1].Hours" />
<!-- Notice the array in the prefix -->
</p>
</form>
And the controller:
[HttpPost]
public RedirectToRouteResult CreateTimeSegments(
[Bind(Prefix = "TimeSegment", Include = "Hours,Date,ConsultantID,ProjectID,TaskID")] TimeSegment[] TimeSegments) {
dc.TimeSegments.InsertAllOnSubmit(TimeSegments);
dc.SubmitChanges();
return RedirectToAction("ListTimeSegments");
}
And that's it. Of course you'll want to validate or do other stuff before sending to the database, but that's roughly all there is to it.
UPDATE 2
I believe you can do an IList<TimeSegment> instead of TimeSegment[] without issues, but as far as if it's better, that's up for debate. The way I look at it the browser still sends a virtual array to the server so having the action receive an array feels natural, but its up to you what you want to use.
So, a generic list action would look like this:
[HttpPost]
public RedirectToRouteResult CreateTimeSegments(
[Bind(Prefix = "TimeSegment", Include = "Hours,Date,ConsultantID,ProjectID,TaskID")] IList<TimeSegment> TimeSegments) {
dc.TimeSegments.InsertAllOnSubmit(TimeSegments);
dc.SubmitChanges();
return RedirectToAction("ListTimeSegments");
}
Keep in mind that I haven't used this (meaning the IList) before so I can't guarantee it will work, just speculating...
UPDATE 3
About what you want to do with the Consultant, it sound a lot like what I do with Cookies. I have a BaseView class which is the type used by the Site.Master and then all other views extend from it. In the BaseView I have a Cookie property which is always populated by each controller action. I then use that property to get the id of the currently authorized user.
So, in code it looks like this (using examples from one of my apps):
public class BaseView {
// Don't confuse with an HttpCookie, this is an object in my database...
public Cookie Cookie { get; set;}
}
public class EmployeeView : BaseView {
public Employee Employee { get; set; }
}
And with this, say I want to add a note to an employee, my form would look like this where I pass in a hidden field which is where your ConsultantID comes into play.
<form>
<input type="hidden" name="Note.AuthorId" value="<%=Model.Cookie.EmployeeId%>" />
<!-- other fields -->
</form>
Hope this helps.