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.
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.
Experimenting with Blazor (Server, if that makes any difference), and I'm having difficulty getting binding to a MultiSelectList to work....
Bit of background: I'm dealing with EF Core and have a Many-to-Many relationship, let's say between people and cars. I'm currently loading a page that shows the existing details, and allowing the user to update this page.
So in my Service, I load my Person entity from the DB, and this includes the details of all the cars they currently own. I also load the list of all the available cars. My Service method then creates a MultiSelectList and adds it to my ViewModel (to be returned to the Razor Page):
Service method
vm.CarSelector = new MultiSelectList(
allCars,
nameof(Car.CarId),
nameof(Car.Name),
person.OwnedCars.Select(oc => oc.CarId));
This is fictitious code, but I hope you get the picture. When debugging this (in the Service method) I can see that this MultiSelectList has an entry for every car, and the ones that are already selected are showing as Selected. Great!
Blazor Razor Page
So, this is where I come unstuck.... I can't work out how to do the two-way data-binding of a Razor control to this object.
I'm trying to use an <InputSelect />, but that might not be the best control to use.
ideally (actually, that's more of a "must have"), each option should have CheckBox.
I'm wondering whether the use of a MultiSelectList really buys me anything
Checkboxes are a bit different in blazor. Normally you would use the bind-value attribute on an input element as shown below, however, this is not recommended as you will only be able to read the value and NOT update the UI by changing the boolean value via code:
<input type="checkbox" #bind-value="#item.Selected"/>
Instead, use the #bind syntax for checkboxes, which is much more robust and will work both ways (changing the bound boolean value from code & interacting with the checkbox on the UI). See the syntax below:
<input type="checkbox" #bind="#item.Selected"/>
The bind attribute will automatically bind your boolean value to the "checked" property of the html element.
Also make sure you are binding to the "Selected" property rather than the "Value" property.
Using the built in bind will prevent the need to manually setup events as you did in your answer. You can also get rid of the if/else block and merge your code into a single code flow since you are now binding to the boolean rather than setting the checked property manually. If you still need to tap into an event to fire off some process(maybe hiding parts of UI on checking a box), I'd suggest using the onclick event and manually passing in the multiselect Item for each line. Here is the final code:
#foreach(var item in list)
{
<input type="checkbox" #bind="item.Selected" #onclick="(()=>handleClick(item))" />
}
#foreach(var item in list.Where(x=>x.Selected))
{
<p> Item #item.Text is Selected</p>
}
#code {
MultiSelectList list = new MultiSelectList(new List<Car> { new Car { Year = 2019, Make = "Honda", Model = "Accord" }, new Car { Make = "Honda", Model = "Civic", Year = 2019 } });
private void handleClick(SelectListItem item)
{
//Do something crazy
}
}
I got this to work with a component that takes the MultiSelectList as a parameter. There may be more elegant ways to achieve this (please do update if you know of a better way).
#using Microsoft.AspNetCore.Components
#using Microsoft.AspNetCore.Mvc.Rendering
<div class="multiselect">
<div id="checkboxes">
#foreach (var item in this.Items)
{
<div>
<label for="#item.Value">
#if (item.Selected)
{
<input type="checkbox" id="#item.Value" checked="checked" #onchange="#((e) => CheckboxChanged(e, item.Value))" />
}
else
{
<input type="checkbox" id="#item.Value" #onchange="#((e) => CheckboxChanged(e, item.Value))" />
}
#item.Text
</label>
</div>
}
</div>
</div>
#code
{
[Parameter]
public MultiSelectList Items { get; set; } = null!;
private void CheckboxChanged(ChangeEventArgs e, string key)
{
var i = this.Items.FirstOrDefault(i => i.Value == key);
if (i != null)
{
i.Selected = (bool)e.Value;
}
}
}
This is a follow up to a question that was asked yesterday.
I have a viewmodel, which shows a list of objectives. Using jquery I can add a new objectives line to the screen (the ID is set to 0 for any new objectives listed). When I click on the Save button to Post the objective list back to the controller, the controller loops through the objective list, and checks the ID against the database. If the ID is NOT found, it creates a new objective, adds this to the DB context, and saves te changes. It then retreives the ID, and returns the View(model) to the View.
The problem is, although the ID in the model, is updated to the database ID - when the model is rendered in the View again, it's ID is still 0. So if I click Save again, it again, re-adds the "new objective added previously" to the database again.
My controller is shown below:
//
// POST: /Objective/Edit/model
[HttpPost]
public ActionResult Edit(ObjectivesEdit model)
{
if (model.Objectives != null)
{
foreach (var item in model.Objectives)
{
// find the database row
Objective objective = db.objectives.Find(item.ID);
if (objective != null) // if database row is found...
{
objective.objective = item.objective;
objective.score = item.score;
objective.possscore = item.possscore;
objective.comments = item.comments;
db.SaveChanges();
}
else // database row not found, so create a new objective
{
Objective obj = new Objective();
obj.comments=item.comments;
obj.objective = item.objective;
obj.possscore = item.possscore;
obj.score = item.score;
db.objectives.Add(obj);
db.SaveChanges();
// now get the newly created ID
item.ID = obj.ID;
}
}
}
return View(model);
}
My ID is being set in the controller:
EDIT: Another example here, showing model.Objectives1.ID being updated:
However when the view renders it, it reverts to 0:
The Objectives list is determined as follows:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace MvcObjectives2.Models
{
public class ObjectivesEdit
{
public IEnumerable<Objective> Objectives { set; get; }
public ObjectivesEdit()
{
if (Objectives == null)
Objectives = new List<Objective>();
}
}
}
The View has:
#model MvcObjectives2.Models.ObjectivesEdit
#using (Html.BeginForm())
{
#Html.EditorFor(x=>x.Objectives)
<button type="submit" class="btn btn-primary"><i class="icon-ok icon-white"></i> Save</button>
}
and in my EditorTemplate (objective.cshtml):
#model MvcObjectives2.Models.Objective
<div class="objec">
<div>
#Html.TextBoxFor(x => x.objective})
</div>
<div>
#Html.TextBoxFor(x => x.score})
</div>
<div>
#Html.TextBoxFor(x => x.possscore})
</div>
<div>
#Html.TextBoxFor(x => x.comments})
#Html.HiddenFor(x => x.ID) // This is the ID where it should now show the new ID from the database, but shows 0
</div>
</div>
I suspect the issue is somewhere in my controller - but I would appreciate any advise on how to get my View to render the new ID of the added objective.
After rewording my search, I came across several posts which say this is by design. A Posted form expects to display what it sent to the controller, if the same page is shown again.
However, you can add this, which will flush ModelState, and apparantly show the updated values from the model, updated in the controller:
ModelState.Clear();
return View(model);
I'm not certain if this has any other effect yet - but for now, it appears to work ok.
Thanks, Mark
The Html.HiddenFor has bitten me before in a similar scenario. The problem is when using this Html helper the hidden value is not updated on the re-post.
If you post something from the form and change it inside your controller, when you re-render the page using it will use the value which was originally posted to the action.
Instead use
<input type="hidden" name="ID" id="ID" value="#Html.Encode(Model.ID)" />
I am trying to render multiple Views using a loop like this
#model IEnumerable<RamtaJogi.Web.Razor.Controllers.IMenuRenderer>
#foreach (var item in #Model)
{
{#Html.RenderPartial(#item.ViewName, #item.ViewData);}
<br />
}
here is my IRenderer
public interface IMenuRenderer
{
string ViewName { get; }
object ViewData { get; }
}
But it throws an error CS1502: The best overloaded method match for 'System.Web.WebPages.WebPageExecutingBase.Write(System.Web.WebPages.HelperResult)' has some invalid arguments
I pass a collection of objects of type IMenuRenderer to my view.
Any idea what is wrong with my codes. Can someone help here.
Regards
Parminder
You have too many # characters.
You should only use #s to enter the foreach.
Since RenderPartial returns void, you cannot print its result with an #.
Parameters also never get #s.
Change your code to
#model IEnumerable<RamtaJogi.Web.Razor.Controllers.IMenuRenderer>
#foreach (var item in Model)
{
#Html.Partial(item.ViewName, item.ViewData)
<br />
}
You can create a custom helper.I think this will help you. ASP.NET MVC: Custom Html Helpers in Razor
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.