What is the defined behavior for form binding in ASP.NET/MVC if you POST a form and its action has query parameters and you have form data?
For example:
<form action="my/action?foo=1" method="post">
<input type="hidden" name="bar" value="2">
</form>
If such a form is submitted should the controller get both foo and bar or only one of them?
The controller will get both values. The default model binder will try to find matches for the parameters from both the URI (either query string or route parameters) or the body (and forms data is supported out-of-the-box).
Note, you can see this is supported by Html.BeginForm helper, you do so through routeValues:
#Html.BeginForm("ActionName", "ControllerName", new { foo = "1" })
It essentially generates the same html as your form tag, but wanted to post for those who find this question and want to know how to pass additional values that are not part of the form using the BeginForm helper.
I think it should be able to get both. In this case, I would create a ViewModel that contains two string or int properties, one named 'foo' and the other named' bar' and have your ActionResult accept the ViewModel. You should see both values come in.
Related
I have simple web application written using Springboot and Thymeleaf templates. Report controller receives the data from form and builds the TestPlanReportResponse object which is added as model attribute like this:
#PostMapping("/report")
public String homeSubmit(#ModelAttribute HomeFormInput homeFormInput, Model model, Errors errors) {
final TestPlanReportResponse response = new TestPlanReportResponse(homeFormInput);
model.addAttribute("allData", response);
return "charts";
}
I can work with that data in "charts" thymeleaf template and show the data I need, but I need to send exactly the same object back to controller when button is clicked, but i getting TestPlanReportResponse
object as parameter with nulls set.
#PostMapping("/report/send")
public String sendReport(#ModelAttribute TestPlanReportResponse reportData, Model model) {
//reportData contains just nulls
}
Here is how my button is set in charts template:
<form action="#" th:action="#{/report/send}" th:object="${allData}" method="post">
<button type="submit">Send the report</button>
</form>
So my question is how to send the object back from thymeleaf template? Should i create a hidden input and put there the "allData" object just to send it back? It looks for me like dirty hack. What would be the appropriate way to pass data back? I want to have this app stateless so don't to store the data on a server side.
When I used to work with Spring and Thymeleaf and form, we had the same issue, passing the data back and forth between a form, the template, and different controllers.
And what you suggest is what we did, we used hidden input as dirty as it may look,it was the standard suggested answer, we did not find anything better.
You need to create an input, with a type a value and link it to a field, like this:
<form action="#" th:action="#{/report/send}" th:object="${allData}" method="post">
<input type="hidden" th:value="*{allDataValue1}" th:field="*{allDataField1}" />
//Do this for all your attributes/values that you wish to pass to the controller
<button class="btn btn-info btn-lg btn-block" type="submit">Send the report</button>
</form>
Though, i found this answer, you can try looking into this thread
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 strongly typed razor view for a model in my MVC 3 project. Basically its for editing the model.
The model contains an Id field for the database key and some other string fields (Its a viewModel and all but thats not the point of the question).
In the view I just have a form and a submit button and nothing else. When the View is posted to the controller the model in the controller has all fields empty EXCEPT for the Id field which seems to have been auto-magically filled up.
How and where does the Id field gets populated in the model without there being a corresponding 'input' element for it in the view.
This is probably a dumb question but I would appreciate even just a link to what I should read up on. Thanks.
I bet it comes from the url as route parameter.
For example you have the following controller:
public class HomeController: Controller
{
public ActionResult Index(int id)
{
vqr model = GetModel(id);
return View(model);
}
[HttpPost]
public ActionResult Index(MyViewModel model)
{
// the model.Id property will be automatically populated here
// because the request was POST /home/index/123
...
}
}
and the following view:
#model MyViewModel
#using (Html.BeginForm())
{
<button type="submit">OK</button>
}
Now you navigate to GET /home/index/123 and you get the following markup:
<form action="/home/index/123" method="post">
<button type="submit">OK</button>
</form>
Notice the action attribute of the form? That's where the id comes from. Basically the Html.BeginForm() helper uses the current url when generating the action attribute, and since the current url is /home/index/123 it is what gets used.
And because if you have left the default routes in your Global.asax, the {id} route token is used at the end of the url, the default model binder successfully binds it to the Id property of your view model.
You are probably hitting a URL similar to the following: /MyObject/Edit/15
This is then returning the page that you have your blank form on.
What happens next is you have an HTML.BeginForm() which is posting BACK to /MyObject/Edit/15
Now because of the post back having the same format your routing rules are picking up the '15' and binding it back to your id.
Have you added the ID field as a hidden field?
e.g.
#Html.HiddenFor(x=> x.ID)
I want to pass two values from view to controller . i.e., #Model.idText and value from textbox. here is my code:
#using HTML.BeginForm("SaveData","Profile",FormMethod.Post)
{
#Model.idText
<input type="text" name="textValue"/>
<input type="submit" name="btnSubmit"/>
}
But problem is if i use "Url.ActionLink() i can get #Model.idText . By post action i can get textbox value using FormCollection . But i need to get both of this value either post or ActionLink
using ajax you can achieve this :
don't use form & declare your attributes like this in tags:
#Model.idText
<input type="text" id="textValue"/>
<input type="submit" id="btnSubmit"/>
jquery:
$(function (e) {
// Insert
$("#btnSubmit").click(function () {
$.ajax({
url: "some url path",
type: 'POST',
data: { textField: $('#textValue').val(), idField: '#Model.idText' },
success: function (result) {
//some code if success
},
error: function () {
//some code if failed
}
});
return false;
});
});
Hope this will be helpful.
#using HTML.BeginForm("SaveData","Profile",FormMethod.Post)
{
#Html.Hidden("idText", Model.idText)
#Html.TextBox("textValue")
<input type="submit" value="Submit"/>
}
In your controller
public ActionResult SaveData(String idText, String textValue)
{
return null;
}
I'm not sure which part you are struggling with - submitting multiple values to your controller, or getting model binding to work so that values that you have submitted appear as parameters to your action. If you give more details on what you want to achieve I'll amend my answer accordingly.
You could use a hidden field in your form - e.g.
#Html.Hidden("idText", Model.idText)
Create a rule in global.asax and than compile your your with params using
#Html.ActionLink("My text", Action, Controller, new { id = Model.IdText, text =Model.TextValue})
Be sure to encode the textvalue, because it may contains invalid chars
Essentially, you want to engage the ModelBinder to do this for you. To do that, you need to write your action in your controller with parameters that match the data you want to pass to it. So, to start with, Iridio's suggestion is correct, although not the full story. Your view should look like:
#using HTML.BeginForm("SaveData","Profile",FormMethod.Post)
{
#Html.ActionLink("My text", MyOtherAction, MaybeMyOtherController, new { id = Model.IdText}) // along the lines of dommer's suggestion...
<input type="text" name="textValue"/>
<input type="submit" name="btnSubmit"/>
#Html.Hidden("idText", Model.idText)
}
Note that I have added the #Html.Hidden helper to add a hidden input field for that value into your field. That way, the model binder will be able to find this datum. Note that the Html.Hidden helper is placed WITHIN your form, so that this data will posted to the server when the submit button is clicked.
Also note that I have added dommer's suggestion for the action link and replaced your code. From your question it is hard to see if this is how you are thinking of passing the data to the controller, or if this is simply another bit of functionality in your code. You could do this either way: have a form, or just have the actionlink. What doesn't make sense is to do it both ways, unless the action link is intended to go somewhere else...??! Always good to help us help you by being explicit in your question and samples. Where I think dommer's answer is wrong is that you haven't stated that TextValue is passed to the view as part of the Model. It would seem that what you want is that TextValue is entered by the user into the view, as opposed to being passed in with the model. Unlike idText that IS passed in with the Model.
Anyway, now, you need to set up the other end, ie, give your action the necessary
[HttpPost]
public ActionResult SaveData(int idText, string textValue) // assuming idText is an int
{
// whatever you have to do, whatever you have to return...
}
#dommer doesn't seem to have read your code. However, his suggestion for using the Html.ActionLink helper to create the link in your code is a good one. You should use that, not the code you have.
Recapping:
As you are using a form, you are going to use that form to POST the user's input to the server. To get the idText value that is passed into the View with the Model, you need to use the Html.Hidden htmlhelper. This must go within the form, so that it is also POSTed to the server.
To wire the form post to your action method, you need to give your action parameters that the ModelBinder can match to the values POSTed by the form. You do this by using the datatype of each parameter and a matching name.
You could also have a complex type, eg, public class MyTextClass, that has two public properties:
public class MyTextClass
{
public int idText{get;set}
public string TextValue{get;set;}
}
And then in your controller action you could have:
public ActionResult SaveData(MyTextClass myText)
{
// do whatever
}
The model binder will now be able to match up the posted values to the public properties of myText and all will be well in Denmark.
HTH.
PS: You also need to read a decent book on MVC. It seems you are flying a bit blind.
Another nit pick would be to question the name of your action, SaveData. That sounds more like a repository method. When naming your actions, think like a user: she has simply filled in a form, she has no concept of saving data. So the action should be Create, or Edit, or InformationRequest, or something more illustrative. Save Data says NOTHING about what data is being saved. it could be credit card details, or the users name and telephone...
I know that in the html helper BeginForm available in asp.net mvc there is a param called htmlAttributes. How can I use it witouth specify the previous params? I don't want to override the default action/method values
You could do something like this:
#using(Html.BeginForm(ViewContext.RouteData.Values["action"].ToString(), ViewContext.RouteData.Values["controller"].ToString(), FormMethod.Post, new{title = "title"}))
{
...
}
which outputs:
<form action="/" class="someclass" method="post">
</form>
It's not exaclty what you wanted and it's not pretty. You do have to specify the FormMethod.
Or add the attributes you need via jQuery.
Passing null as the value of the BeginForm function will apply the default params value