I have the following problem:
I have a form in site/banen (currently local running webserver) which is using a SQL database. The link is made using ADO.net and is instantiated in the controller in the following way:
DBModelEntities _entities;
_entities = new DBModelEntities(); // this part is in the constructor of the controller.
Next, I use this database to fill a Html.DropDownList() in my view. This is done in two steps. At the controller side we have in the constructor:
ViewData["EducationLevels"] = this.GetAllEducationLevels();
and a helper method:
public SelectList GetAllEducationLevels()
{
List<EducationLevels> lstEducationLevels = _entities.EducationLevels.ToList();
SelectList slist = new SelectList(lstEducationLevels, "ID", "Name");
return slist;
}
In the view I have the following:
<% using (Html.BeginForm()) {%>
<fieldset>
<legend>Fields</legend>
<!-- various textfields here -->
<p>
<label for="EducationLevels">EducationLevels:</label>
<!-- <%= Html.DropDownList("EducationLevels", ViewData["EducationLevels"] as SelectList)%> -->
<%= Html.DropDownList("EducationLevels", "..select option..")%>
</p>
<p>
<input type="submit" value="Create" />
</p>
</fieldset>
<% } %>
Now, the form is rendered correctly when I browse to the create page. I can select etc. But when selected I have to use that value to save in my new model to upload to the database. This is where it goes wrong. I have the following code to do this in my controller:
//
// POST: /Banen/Create
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create(FormCollection form)
{
// set rest of information which has to be set automatically
var vacatureToAdd = new Vacatures();
//vacatureToAdd.EducationLevels = form["EducationLevels"];
// Deserialize (Include white list!)
TryUpdateModel(vacatureToAdd);
// Validate
if (String.IsNullOrEmpty(vacatureToAdd.Title))
ModelState.AddModelError("Title", "Title is required!");
if (String.IsNullOrEmpty(vacatureToAdd.Content))
ModelState.AddModelError("Content", "Content is required!");
// Update the variables not set in the form
vacatureToAdd.CreatedAt = DateTime.Now; // Just created.
vacatureToAdd.UpdatedAt = DateTime.Now; // Just created, so also modified now.
vacatureToAdd.ViewCount = 0; // We have just created it, so no views
vacatureToAdd.ID = GetGuid(); // Generate uniqueidentifier
try
{
// TODO: Add insert logic here
_entities.AddToVacatures(vacatureToAdd);
_entities.SaveChanges();
// Return to listing page if succesful
return RedirectToAction("Index");
}
catch (Exception e)
{
return View();
}
}
#endregion
It gives the error:
alt text http://www.bastijn.nl/zooi/error_dropdown.png
I have found various topics on this but all say you can retrieve by just using:
vacatureToAdd.EducationLevels = form["EducationLevels"];
Though this returns a string for me. Since I'm new to ASP.net I think I am forgetting to tell to select the object to return and not a string. Maybe this is the selectedValue in the part where I make my SelectList but I can't figure out how to set this correctly. Of course I can also be complete on a sidetrack.
Sidenote: currently I'm thinking about having a seperate model like here.
Any help is appreciated.
You can't return an object from usual <SELECT> tag wich is rendered by Html.DropDownList() method, but only string variable could be returned. In your case ID of EducationLevels object will be send to the server. You should define and use one more custom helper method to reconstruct this object by ID.
Related
I have following code in view :
<div>
<input type="file" name ="file" onchange="location.href='<%: Url.Action("ChangeImage", new{Id = Model.Id}) %>'" />
</div>
And in Controller I have the ChangeImage method :
public ActionResult ChangeImage(FormCollection collection, int Id,Products products)
{
var file = Request.Files["file"];
//Do something
}
But the selected file does not post to the controller. What is the problem? How can I send the file content to the controller to use it?
Because you are not posting the form data is probably the reason.
When creating an MVC form for submitting files you must specify the "enctype", with the helpers you can do this:
#using (Html.BeginForm("MyAction", "MyController", new { #Id = Model.Id }, FormMethod.Post, new { name = "Form", enctype = "multipart/form-data" }))
{
//all form fields code in here
}
Then you will want to change your javascript to post the form, something like:
document.forms[0].submit();//assuming you only have one form
Also, your action parameters don't seem to match anything. Specifically ShopID and products. You will probably get an error because you don't have default values for them. I am not 100% sure on that part though. Or maybe you have then in other parts of your form, so it might be ok
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 starting a new project in Asp.net MVC 2.
I have been mostly a webforms developer and have limited exposure to Asp.Net MVC and hence this is probably a noob question.
My situation is as follows:
I have a create page for saving some data to the DB.
The view for this page is not strongly bound / typed - so the way I am extracting the data from the view is by looking at the POST parameters.
Incase there is an error (data validation, etc), I need to send the user back to the previous page with everything filled in the way it was and displaying the message.
On webforms, this got handled automatically due to the view state - but how can I go about doing the same here?
A code example can be as follows:
View:
<% using (Html.BeginForm("Create", "Question", FormMethod.Post)) { %>
<div>
Title: <%: Html.TextBox("Title", "", new { #style="width:700px" })%>
</div>
<div>
Question: <%: Html.TextBox("Question", "", new { #style="width:700px" })%>
</div>
<input type="submit" value="Submit" />
<% } %>
Controller:
[HttpPost]
[ValidateInput(false)]
public ActionResult Create() {
Question q = new Question();
q.Title = Request.Form["Title"];
q.Text = Request.Form["Question"];
if(q.Save()) {
return RedirectToAction("Details", new { id = q.Id });
}
else {
// Need to send back to Create page with data filled in
// Help needed here
}
}
Thanks.
You could simply return the View in case of error. This will preserve the context.
[HttpPost]
[ValidateInput(false)]
public ActionResult Create(Question q) {
if(q.Save()) {
return RedirectToAction("Details", new { id = q.Id });
}
else {
// Need to send back to Create page with data filled in
// Help needed here
return View();
// If the view is located on some other controller you could
// specify its location:
// return View("~/Views/Question/Create.aspx");
}
}
Also I would recommend you to use strongly typed views along with the strongly typed helpers. Notice how I used a Question object directly as action parameter. This is equivalent to the code you have written in which you were manually extracting and building this object. The model binder does this job automatically for you.
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.
I have following problem. In my view model I defined some list properties as follows:
public class BasketAndOrderSearchCriteriaViewModel
{
List<KeyValuePair> currencies;
public ICollection<KeyValuePair> Currencies
{
get
{
if (this.currencies == null)
this.currencies = new List<KeyValuePair>();
return this.currencies;
}
}
List<KeyValuePair> deliverMethods;
public ICollection<KeyValuePair> DeliveryMethods
{
get
{
if (this.deliverMethods == null)
this.deliverMethods = new List<KeyValuePair>();
return this.deliverMethods;
}
}
}
This view model is embedded in another view model:
public class BasketAndOrderSearchViewModel
{
public BasketAndOrderSearchCriteriaViewModel Criteria
{
[System.Diagnostics.DebuggerStepThrough]
get { return this.criteria; }
}
}
I use 2 action methods; one is for the GET and the other for POST:
[HttpGet]
public ActionResult Search(BasketAndOrderSearchViewModel model){...}
[HttpPost]
public ActionResult SubmitSearch(BasketAndOrderSearchViewModel model){...}
In the view I implement the whole view model by using the EditorFor-Html Helper which does not want to automatically display DropDownLists for List properties!
1. Question: How can you let EditorFor display DropDownLists?
Since I could not figure out how to display DropDownLists by using EditorFor, I used the DropDownList Html helper and filled it through the view model as follows:
public IEnumerable<SelectListItem> DeliveryMethodAsSelectListItem()
{
List<SelectListItem> list = new List<SelectListItem>();
list.Add(new SelectListItem()
{
Selected = true,
Text = "<Choose Delivery method>",
Value = "0"
});
foreach (var item in this.DeliveryMethods)
{
list.Add(new SelectListItem()
{
Selected = false,
Text = item.Value,
Value = item.Key
});
}
return list;
}
My 2. question: As you can see I pass my view model to the action metho with POST attribute! Is there a way to get the selected value of a DropDownList get binded to the passed view model? At the moment all the DropDownList are empty and the selected value can only be fetched by the Request.Form which I definitely want to avoid!
I would greatly appreciate some ideas or tips on this!
For those like me that got to this post these days I'd recommend you to fully download the tutorial from http://www.asp.net/mvc/tutorials/mvc-music-store-part-1 which covers this and most of the common techniques related with .NET MVC applications.
Anyway Really usefull your post and answers man (If I could vote you I would :)
Let's try to take on this one:
Answer to Question 1: How can you let EditorFor display DropDownLists?
When you call Html.EditorFor() you can pass extra ViewData values to the EdiorTemplate View:
<%: Html.EditorFor(model => Model.Criteria, new { DeliveryMethods = Model.DeliveryMethods, Currencies = Model.Currencies}) %>
Now you have ViewData["DeliveryMethods"] and ViewData["Currencies"] initialized and available inside your EditorTemplate.
In your EditorTemplate you somehow need to call and convert those entries into DropDowns / SelectLists.
Assuming you've got an ascx file of type System.Web.Mvc.ViewUserControl<BasketAndOrderSearchCriteriaViewModel> you could do the following:
<%: Html.LabelFor(model => model.DeliveryMethods) %>
<%: Html.DropDownList("SelectedDeliveryMethod", new SelectList(ViewData["DeliveryMethods"] as IEnumerable, "SelectedDeliveryMethod", "Key", "value", Model.SelectedDeliveryMethod)) %>
Same goes for the Currencies.
<%: Html.LabelFor(model => model.Currencies) %>
<%: Html.DropDownList("SelectedCurrency", new SelectList(ViewData["Currencies"] as IEnumerable, "SelectedDeliveryMethod", "Key", "value", Model.SelectedCurrency)) %>
This setup will make your DeliveryMethodAsSelectListItem() obsolete and you can use any kind of list. Means you are not bound to KeyValuePairs. You'll just need to adjust your call on Html.DropDownList() from now on.
As you can see, I have introduced some new properties to your BasketAndOrderSearchCriteriaViewModel:
Model.SelectedDeliveryMethod
Model.SelectedCurrency
They are used to store the currently selected value.
Answer to Question 2: Is there a way to get the selected value of a DropDownList get binded to the passed view model?
In the EditorFor template we are passing the newly created Model.SelectedDeliveryMethod and Model.SelectedCurrency properties as the SelectedValue Parameter (See 4th Overload of the DropDownList Extension Method).
Now that we have the View doing it's job: How can we get the currently selected value inside the POST Action?
This is really easy now:
[HttpPost]
public ActionResult SubmitSearch(BasketAndOrderSearchViewModel model)
{
...
var selectedDeliveryMethod = model.Criteria.SelectedDeliveryMethod;
var selectedCurrency model.Criteria.SelectedDeliveryMethod;
...
}
Note: I don't have an IDE to test it right now, but it should do the trick or at least show you in which direction to go.