As you can see here, I'm allowing a user to dynamically create a table of data, and storing the ids of the table in a hidden field (in the example it's a text area so you can see it, and the final solution will be Guid rather than integers).
My question is simply this: What data type should I use on the server/MVC action to take the data held in the textarea/hidden field?
At the moment I have a string, and am contemplating doing a load of .split()'ing and whatnot, but it doesn't feel right!
Ultimately I need some sort of IEnumerable<Guid, Guid> thing?!?! so I can do a foreach and get each pair of Ids.
I'm sure the answer will be simple, but I can't think of what to do.
Any help appreciated.
If your UI has multiple, like-named form fields, they will be submitted to your action method and bound properly to an array. We could use string[] for this case.
<form action="">
<input type="text" name="guids"/>
<input type="text" name="guids"/>
<input type="text" name="guids"/>
<input type="text" name="guids"/>
<input type="submit" value="Submit"/>
</form>
Then your controller could handle them like so:
public ActionResult MyAction(string[] guids)
{
guids.Count == 4 // if all four fields were filled in.
}
Note that if there is just a single guids value sent by the form, the string[] guids will still work - it will contain just a single item.
Finally, note that if no values are entered, the array value will be null, not an empty array.
You can actually bind to a list from your model, take a look at this post
http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx
Related
I am looking for a way to pass the whole object through without having to use <input type="hidden" /> on the different variables. It seems like the th:object will not carry over the incoming information on the "whole object"
<form action="#" th:action="#{/api/result/save}" th:object="${result}" th:method="post">
<!--- Input fields -->
<input type="hidden" th:field="${result}"> <---- Not working.
<button type="submit" class="btn btn-primary" value="spara">Spara</button>
From the model I have
Result result = new Result(teams);
result.setTeam1ID(aTeam1.get().getId()); // This variable will not be changed in the HTML so I would like to pass that to the next page
// Other variables
When I get to the /save the Result will only contain variables set in Thymeleaf it will not retain the information from the original model above.
#PostMapping("/save")
public RedirectView saveResult(Result result, Model model) {
service.saveResult(result);
Thymeleaf is use to generate view, you can store some variable but not the whole object.
Though you can try these method:
If you object is already stored at server-side in memory or data base. You just pass the unique key of that object get it back using hidden input type.
Store the object into session then get it from there whenever requered.
This is an add page. Person contains a list of addresses so when i try to add an address to that person that is not yet in the database i need to be able to retrieve the person form when an address is submitted and assign that address to that person.
<form:form action="${addAction}" modelAttribute="person">
<form:label path="name">
<spring:message text="Name"/>
</form:label>
<form:input path="name" />
... More labels and inputs
</form:form>
<form:form action="${addAddress}" modelAttribute="address">
... Labels
<input type="submit" value="<spring:message text="Add Address"/>" />
</form:form>
In my controller i have "#ModelAttribute("person") Person p" line which should retrieve the form which has "modelAttribute="person"" in it. But the person retrieved is an empty entity which i'm assuming is because the person form has to be submitted in order to retrieve the data.
#RequestMapping(value = "/person/addAddress", method = RequestMethod.POST)
public String addAddress(#ModelAttribute("person") Person p, #ModelAttribute("address") Address a, RedirectAttributes redirectAttrs) {
p.getAddresses().add(a);
redirectAttrs.addFlashAttribute("person", p);
return "redirect:/person";
}
I probably can retrieve the inputs instead of the form and use them to create a new entity with those values but if i were to do that controllers' passing attributes will be full of inputs and would look ugly. Is there a way for me to retrieve those values as a Person entity?
EDIT
Sanjay's first option is the most logical way to do it but since what i wanted to design does not fit for it i can't do it. But Sanjay's comment about making it in one form helped me so i'm selecting Sanjay's answer as the solution but here is how i fixed it
Since i had form actions saved in c:url's i changed the buttons' onclick function such that when clicked forms' action would change depending on the button and i already had corresponding controllers for the actions. For the address list inside my person i had to make a workaround by first adding an empty address to the list in my page controller and then using
<c:forEach items="${person.addresses}" varStatus="loop">
<c:if test="${loop.last}">
<form:input path="addresses[${loop.index}].street" />
...
the code above i was able to fill the previously added empty address.
I'm still in the process of fixing everything but this is the general idea of how i fixed it. Thanks for the help.
I think you may need to revisit your UI, add some hidden field etc. I can think of some solutions:
Have an "Add Address" button which appends a blank row of address into the form using JavaScript, but it doesn't submit to the server. Have the real "Submit" button at the bottom, which would submit the entire form including the person and addresses.
Have a submit button to save the person without address. Then, on a second screen, display the person, and have the address submission button.
Do the above, in reverse, if saving the Address first suits your requirements
I probably can retreieve the inputs instead of the form and use them to create a new entity with those values but if i were to do that controllers' passing attributes will be full of inputs and would look ugly. Is there a way for me to retrieve those values as a Person entity?
For cleaner code -
1.Create JSON object (say formFields) with all your form input data.
2.send formFields to server using ajax call.
3.Read formFields as String in controller
#ModelAttribute("formFields") final String formFields
4.You should have DTO matching formFields name say FormDTO.
5.convert formFields of String type to FormDTO using ObjectMapper API.
FormDTO formDto = null;
try {
ObjectMapper mapper = new ObjectMapper();
formDto = mapper.readValue(formDto, FormDTO.class);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
P.S. ObjectMapper is part of jackson-databind-2.4.4.jar
Is it possible to match a ViewModel property to the matching ModelState.Key value when the ViewModel is a (has a) collection?
Example: To edit a collection of viewmodel items, I am using the extension found here.
That adds a GUID to the id of the fields on the page.
example:
class Pets
{
string animal;
string name;
}
For a list of Pets, the generated html source is like this:
<input name="Pets.index" autocomplete="off" value="3905b306-a9..." type="hidden">
<input value="CAT" id="Pets_3905b306-a9...__animal" name="Pets[3905b306-a9...].animal" type="hidden">
<input value="MR. PEPPERS" id="Pets_3905b306-a9...__name" name="Pets[3905b306-a9...].name" type="hidden">
<input name="Pets.index" autocomplete="off" value="23342306-b4..." type="hidden">
<input value="DOG" id="Pets_23342306-b4...__animal" name="Pets[23342306-b4...].animal" type="hidden">
<input value="BRUTICUS" id="Pets_23342306-b4...__name" name="Pets[23342306-b4...].name" type="hidden">
So when this gets bound on post, the ModelState gets loaded with all the form fields.
In ModelSTate.Keys, there is:
Pets[23342306-b4...].name
Pets[23342306-b4...].animal
Pets[3905b306-a9...].name
Pets[3905b306-a9...].animal
Everything good so far, but I am doing some business logic validation, things like, cant add new animal if one exists with the same name. In that case, I want to be able to highlight the input field that is in error.
So if my create function fails, it will return an error/key value pair like this:
{ error = "Duplicate Name", key="name" }
So I at least will now what property caused the problem.
But since my repository functions don't know about the view field ids, how can I match the key "name" to the appropriate ModelState key (in this case, either Pets[23342306-b4...].name or Pets[3905b306-a9...].name)?
If you used the built in functionality of MVC for displaying collections (Html.DisplayFor(m => m.Pets) or Html.EditorFor(m => m.Pets)) with appropriate display/editor template, MVC would render something like this:
Pets[0].name
Pets[0].animal
Pets[1].name
Pets[1].animal
This maps to IEnumerable<Pets> and you know that first item has index of 0, second item 1 etc.
So if the second item has an error, you can set error for the ModelState key "Pets[1].name" for example.
If you are using the Html.BeginCollectionItem extension method, like I was, I was able to get around this by not using the GUID. I need the dynamic add and delete, but I was always looking up known items, persons that have an ID, which I had in my editor. So instead of using the GUID, I just assign the ID (uniqueId) in the code below. I could then find the key because I knew it was Person[234232]. Of course if you are adding new items and not displaying selected items, it might not work for you.
public static IDisposable BeginCollectionItem(this HtmlHelper html, string collectionName, string uniqueId)
{
var idsToReuse = GetIdsToReuse(html.ViewContext.HttpContext, collectionName);
string itemIndex = idsToReuse.Count > 0 ? idsToReuse.Dequeue() : uniqueId;
// autocomplete="off" is needed to work around a very annoying Chrome behaviour whereby it reuses old values after the user clicks "Back", which causes the xyz.index and xyz[...] values to get out of sync.
html.ViewContext.Writer.WriteLine(string.Format("<input type=\"hidden\" name=\"{0}.index\" autocomplete=\"off\" value=\"{1}\" />", collectionName, html.Encode(itemIndex)));
return BeginHtmlFieldPrefixScope(html, string.Format("{0}[{1}]", collectionName, itemIndex));
}
I have a form with the autocomplete attribute set to off.
Inside this form, there is a hidden input element (generated using ASP.NET MVC's Html.HiddenFor() method, but, that should be irrelevant):
<input type="hidden" value="0" name="Status" id="Status" data-val-required="The Status field is required." data-val-number="The field Status must be a number." data-val="true">
When the form is submitted, this value is incremented by one and the model is returned to the view. If I write the status value to the page, I can see that the value was correctly incremented.
However, this hidden input field is always cached. It's never getting the correct value. I tried setting the autocomplete attribute directly on the input element, but without success.
How can I get this hidden field to get the correct value? I'd prefer not to use any Javascript.
Edit: Supplying more code...
Controller
//This code is being executed, and the status is being incremented.
shippingOrder.Status = (shippingOrder.Status != (int)OrderStatus.Closed) ? shippingOrder.Status + 1 : shippingOrder.Status;
View
#using (Html.BeginForm("Number", "Order", FormMethod.Post, new { id = "orderSummary", autocomplete = "off" })) {
...
#Html.HiddenFor(m => m.Status)
}
According to this post here html helpers such as HiddenFor will always first use the posted value and after that the value in the model.
As you said, when writing the value to the page you can see it incremented, yet the helper is using the previously posted value, which is the intended behaviour.
The link does suggest the use of ModelState.Remove("Status") or ModelState.Clear() before assigning the new value.
It also suggest that another option could be not using a HiddenFor helper but instead to build the hidden field yourself. Similar to this:
<input type="hidden" name="Status" value="#Model.Status" />
Either way it looks like your problem is based on similar circumstances.
I have a partial template that uses a User object as a model. The user has a collection of Accounts. On this partial template I have a loop as follows. The _Account partial template is bound to the Account class
#foreach (var item in Model.Accounts)
{
<tr>
<td colspan="6">
<div>
#Html.Partial("_Account", item)
</div>
</td>
</tr>
}
In my controller method I initially tried
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult UserDetails(User user, string actionType)
But the User.Accounts collection is empty. Then I tried this. Still the Accounts collection is empty.
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult UserDetails(User user,
[Bind(Prefix="User.Accounts")]
FixupCollection<Account> Accounts,
string actionType)
Can I use the default Modelbinder implementation to achieve this or do I need to do anything different?
Yep, you can use the default model binder. You just need to name your fields correctly. So you need your loop to output something like this:
...
<input type="text" name="user.Accounts[0].SomeTextField" />
<input type="text" name="user.Accounts[0].SomeOtherTextField" />
...
<input type="text" name="user.Accounts[1].SomeTextField" />
<input type="text" name="user.Accounts[1].SomeOtherTextField" />
...
If you need to add/remove accounts, the hardcoded indexes get a little trickier. You could re-assign the names using javascript before postback. But it's all possible. This question gives more detail on model binding:
ASP.NET MVC: Binding a Complex Type to a Select
Use Editor Templates instead of a partial view - no need to hard code your indexes as the template will automagically index all your objects correctly, even when you add and remove Accounts. See my answer to this question:
Pass values from multiple partial views
Small write up on Editor Templates here:
codenodes.wordpress.com - MVC3 Editor Templates