I have a problem with calls to action with POST attribute exclusively from Grid.MVC tool.
I set up a column within the Grid.MVC tool, setting the property RenderValueAs follows:
#Html.Grid(Model).Columns(columns =>
{
// other lines...
columns.Add().Encoded(false)
.Sanitized(false)
.RenderValueAs(item => Html.ActionLink("Delete", "Delete", new { item.ID }));
}).WithPaging(3).Sortable(true)
In my controller I have set the following code which refers to the Delete action:
[HttpPost]
public ActionResult Delete(int id)
{
// anything here
return RedirectToAction("Index");
}
The best practices tell you that the action method should support only POST requests, because deleting objects is not an idempotent operation. This because browsers and caches are free to make GET requests without the user’s explicit consent, and so I must be careful to avoid making changes as a consequence of GET requests.
But, when I try to apply this configuration I have the next error:
Server Error in application '/'
Can not find the resource.
Description: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable. Please review the following URL and make sure that it is spelled correctly
But if I remove the [HttpPost] attribute the code works. Is this behavior correct?
Thanks
UPDATE:
Bayu, you have reason, now I explain the problem from another scenario: I had my View as follows:
<table>
<tr>
<th>ID</th>
#*another columns*#
<th>Name</th>
<th>Actions</th>
</tr>
#foreach (var item in Model)
{
<tr>
<td>#item.ID</td>
#*another columns*#
<td>#item.Name</td>
<td>
#using (Html.BeginForm("Delete", "Admin"))
{
#Html.Hidden("ID", item.ID)
<input type="submit"
value="Delete row" />
}
</td>
</tr>
}
</table>
That is, I used HTML tables, and therefore I could use an input to build a button that allows me to delete a row from the table.
Now, I want to use the tool Grid.View (because among other benefits allows me effortlessly filter columns), but I can not use an input for this purpose.
You have any idea how?
Change new { item.ID }) to new {id = item.ID })
I have a partial view that is bound to an object Cart. Cart has a collection of CartLines. My view is below:
<tbody>
<% foreach (var line in Model.Lines) { %>
<tr>
<td align="center"><%=Html.CatalogImage(line.Product.DefaultImage, 80) %></td>
<td align="left">
<%=Html.ActionLink(line.Product.Name, "Product", "Catalog",
new { productId = line.Product.Id }, new { title = "View " + line.Product.Name })%>
</td>
<td align="right"><%= line.Product.Price.ToString("c")%></td>
<td align="center">
<%=Html.Hidden("lines[" + i + "].key", line.Product.Id) %>
<%=Html.TextBox("lines[" + i + "].value", line.Quantity, new { #class = "quantity" })%>
</td>
<td align="right"><%= (line.LineTotal).ToString("c")%></td>
<td>
<%using (Ajax.BeginForm("RemoveFromCart", "Cart",
new {ProductId = line.Product.Id, returnUrl = ViewData["returnUrl"]},
new AjaxOptions { UpdateTargetId="cart", LoadingElementId="loading" }))
{%>
<input type="image" src="<%=AppHelper.ImageUrl("delete.gif")%>" value="Remove item" />
<%} %>
</td>
</tr>
<% i++; } %>
</tbody>
There are two things to note. The first is that I am using a form per line for removing items.
The second is that I had attempted to allow users to change the quantity of line items and then click an update button to pass all the changes to the controller action:
// POST: /Cart/Update
[HttpPost]
public ActionResult Update(Cart cart, IDictionary<int,int> lines, string returnUrl)
{
foreach (var line in lines) {
Product p = _catalogService.GetProduct(line.Key);
cart.UpdateItem(p, line.Value);
}
if (Request.IsAjaxRequest())
return PartialView("Cart", cart);
else
return RedirectToAction("Index", new { returnUrl });
}
Note that I am using a dictionary since I am only concerned about the product and quantity. I don't really like the fact that I am having to retrieve the product again before calling cart.UpdateItem but I couldn't figure out how to pass the Product from the model to my action instead of the id.
The main problem however, is rather stupidly I wrapped the entire cart in a form so that I could post back the values and then spent a good hour wondering why things were not working correctly in IE - doh! nested forms
So I am stuck on how to get round this. I want the ability to remove items individually but allow a user to change item quantities and then pass all changes at once to the controller. I can't use links for my remove action as I would need to use javascript to force a post and everything must work without javascript enabled.
[Update]
Would a better solution be to allow updates on my custom model binder? This way I could make changes inside my view and post the cart object back to the controller - although I'm not sure whether this is possible with child collections (Cart.CartItems).
I've had a look on sites like Amazon and it would appear they wrap the entire cart in a form and both global update buttons and indidivual remove item buttons post back to the same action when javascript is disabled.
Any help would be appreciated.
Thanks,
Ben
There is only one way here and thats the ugly way. Have 1 form around everything.
Then in the action you have to check which button was pressed (you get the name of the button in the request).
It gets even more ugly with differences in firefox and ie. If you have a button pressed ie or firefox (Dont remember which one) not only sends the name of the pressed button, but also the location where the button was pressed.
You have more options if your solution can rely on JS enabled browsers. But thats another story.
I have an HTML table where each row has buttons which toggle status bits in the database for each row. Assuming Javascript is not an option, what would be the "best practice" way of handling this?
I'm currently handling it by wrapping each row in a form like this:
<table>
<tr>
<td>
<form action="/FooArea/BarController/BazAction" id="frm0" name="frm0" method="post">
<span>Item 1</span>
<input type="submit" value="Toggle1" name="submitButton" />
<input type="submit" value="Toggle2" name="submitButton" />
<input type="hidden" name="itemID" value="1" />
</form>
</td>
</tr>
<tr>
<td>
<form action="/FooArea/BarController/BazAction" id="frm1" name="frm1" method="post">
<span>Item 2</span>
<input type="submit" value="Toggle1" name="submitButton" />
<input type="submit" value="Toggle2" name="submitButton" />
<input type="hidden" name="itemID" value="2" />
</form>
</td>
</tr>
</table>
And the post method looks something like this:
string buttonName = Request.Form["submitButton"];
if (!String.IsNullOrEmpty(buttonName ))
{
int itemID = Convert.ToInt32(Request.Form["itemID"]);
switch (buttonName )
{
case "Toggle1":
DoSomething(itemID);
break;
case "Toggle2":
DoSomethingElse(itemID);
break;
}
}
Any better suggestions? Is having 50 forms on a page cool? I dunno.. let me know what you are doing in this case.
The best way to handle POST scenarios without JavaScript is, as several others have stated, a tiny form with only the necessary values, and only one submit button. Basically, what you should do is to create a helper method that creates a form with the necessary POST values in hidden fields and a submit button. For example, you could have a method you use like this:
<%= Html.PostLink("FooArea/BarController/BazAction", "Toggle1", new List<KeyValuePair<string, string>>{ new KeyValuePair<string, string>("itemId", 1), new KeyValuePair("action", "option1") }); %>
It looks pretty verbose, but I've tried to make it as generic as possible. You can probably create the List<KeyValuePair<string, string>> in the controller when you render the view, so you only have to call something
<%= Html.PostLink("FooArea/BarController/BazAction", "Toggle1", Model.Values) %>
In the action method that handles the post, you bind to the posted FormCollection, and retrieve the values of itemId and action to determine what to do, instead of checking for Request.Form values.
An implementation of the helper method might look like this:
public static string PostLink(this HtmlHelper helper, string postAction, string submitText, IEnumerable<KeyValuePair<string, string>> postValues)
{
var form = new TagBuilder("form");
// Setup basic properties like method, action
form.Attributes.Add("method", "post");
form.Attributes.Add("action", postAction);
// Instantiate a stringbuilder for the inner html of the form
var innerHtml = new StringBuilder();
// Create and append hidden fields for the post values
foreach(var value in postValues)
{
var hidden = new TagBuilder("input");
hidden.Attributes.Add("type", "hidden");
hidden.Attributes.Add("name", value.Key);
hidden.Attributes.Add("value", value.Value);
innerHtml.Append(hidden.ToString(TagRenderMode.SelfClosing));
}
// Create the submit button
var submit = new TagBuilder("input");
submit.Attributes.Add("type", "submit");
submit.Attributes.Add("value", submitText);
// Append it to the stringbuilder
innerHtml.Append(submit.ToString(TagRenderMode.SelfClosing));
// Set the InnerHtml property of the form, and return it
form.InnerHtml = innerHtml.ToString();
return form.ToString(TagRenderMode.Normal);
}
This seems like a prime case for some JQuery and Ajax functionality. But if javascript isn't an option then i think wrapping each one in a form is probably the most simple solution.
When I need to do something like this I do it pretty much the same way as you do here. It is no problem to have multiple forms in one view. Its like having multiple links in one view (but they use POST instead of GET). I guess many .net developers think its wrong because of webforms only having one form tag. In your case I would even create more forms for each submit button as they seem to do different things. I consider having to check the name of the button in the controller to be a code smell. If they do something like activate/deactivate you should probably post that as a bool or something and have both forms post to the same action.
I think technically this is the best way to go. From a usability point of view you can question if this is the best way to do it. More than 20 items in a list can get quite confusing. But ofcourse, I don't really know what you are programming :)
I agree with Mattias about creating different actions for the activate and deactivate-button. This way you avoid having to use a switch-statement.
How should I initiate a delete action from my view?
Creating a new form-tag for each entity just doesn't seem right :-)
<% foreach (var subscriber in group.Subscribers) { %>
<tr>
<td><%= subscriber.Email %></td>
<td><%= Html.ActionLink("[edit]", "edit", "subscriber", new {id=subscriber.SubscriberId}, null) %></td>
<td>
<form id="delete-subscriber-form" method="post" action="<%= Url.Action( "delete", "subscriber", new { #subscriberId = subscriber.SubscriberId }) %>">
<input type="submit" value="Delete" />
</form>
</td>
</tr>
<% } %>
How would you do it?
I normally use checkboxes on the side of the items. Then I can have action links (buttons, whatever) that apply an action to the selected items (such as delete).
you can use CSS and Javascript , add 'forDel' css class for all the elments you want to delete , if you are going to use jquery you can do it like this:
$(".element").each(function(){
$(this).data("id","the id of the element in db")
});
$(".element").toggle(function(){
$(this).addClass("forDel");
},function(){
$(this).removeClass("forDel");
});
and then on pressing the delete button:
var idsForDel;
$(".forDel").each(function(){
idsForDel = $(this).data("id"); + ";";
})
you can pass the idsForDel to the Controller ... and split it in the server side.
It depends on the situation, if you are doing CRUD operations you would normally go with one <form> tag per operation (delete,edit,new). If, however, you are displaying a list and you want to be able to 'multiple delete' items with one click then you will have to approach it from a different angle as you need to encapsulate all the required information into one form.
EDIT
Having had another look at your post above I notice you are providing a 'Delete Button' against each element in the list. For atomic actions like this (i.e. the user expects something to happen straight after they have clicked a button) I would definitely use one form per item.
What I wrote above still applies...
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Your best option is to search for newer questions, or to search the answers below looking for your specific version of MVC, as many answers here are obsolete now.
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(The original question starts below)
This seems a bit bizarre to me, but as far as I can tell, this is how you do it.
I have a collection of objects, and I want users to select one or more of them. This says to me "form with checkboxes." My objects don't have any concept of "selected" (they're rudimentary POCO's formed by deserializing a wcf call). So, I do the following:
public class SampleObject{
public Guid Id {get;set;}
public string Name {get;set;}
}
In the view:
<%
using (Html.BeginForm())
{
%>
<%foreach (var o in ViewData.Model) {%>
<%=Html.CheckBox(o.Id)%> <%= o.Name %>
<%}%>
<input type="submit" value="Submit" />
<%}%>
And, in the controller, this is the only way I can see to figure out what objects the user checked:
public ActionResult ThisLooksWeird(FormCollection result)
{
var winnars = from x in result.AllKeys
where result[x] != "false"
select x;
// yadda
}
Its freaky in the first place, and secondly, for those items the user checked, the FormCollection lists its value as "true false" rather than just true.
Obviously, I'm missing something. I think this is built with the idea in mind that the objects in the collection that are acted upon within the html form are updated using UpdateModel() or through a ModelBinder.
But my objects aren't set up for this; does that mean that this is the only way? Is there another way to do it?
Html.CheckBox is doing something weird - if you view source on the resulting page, you'll see there's an <input type="hidden" /> being generated alongside each checkbox, which explains the "true false" values you're seeing for each form element.
Try this, which definitely works on ASP.NET MVC Beta because I've just tried it.
Put this in the view instead of using Html.CheckBox():
<% using (Html.BeginForm("ShowData", "Home")) { %>
<% foreach (var o in ViewData.Model) { %>
<input type="checkbox" name="selectedObjects" value="<%=o.Id%>">
<%= o.Name %>
<%}%>
<input type="submit" value="Submit" />
<%}%>
Your checkboxes are all called selectedObjects, and the value of each checkbox is the GUID of the corresponding object.
Then post to the following controller action (or something similar that does something useful instead of Response.Write())
public ActionResult ShowData(Guid[] selectedObjects) {
foreach (Guid guid in selectedObjects) {
Response.Write(guid.ToString());
}
Response.End();
return (new EmptyResult());
}
This example will just write the GUIDs of the boxes you checked; ASP.NET MVC maps the GUID values of the selected checkboxes into the Guid[] selectedObjects parameter for you, and even parses the strings from the Request.Form collection into instantied GUID objects, which I think is rather nice.
HtmlHelper adds an hidden input to notify the controller about Unchecked status.
So to have the correct checked status:
bool bChecked = form[key].Contains("true");
In case you're wondering WHY they put a hidden field in with the same name as the checkbox the reason is as follows :
Comment from the sourcecode MVCBetaSource\MVC\src\MvcFutures\Mvc\ButtonsAndLinkExtensions.cs
Render an additional <input
type="hidden".../> for checkboxes.
This addresses scenarios where
unchecked checkboxes are not sent in
the request. Sending a hidden input
makes it possible to know that the
checkbox was present on the page when
the request was submitted.
I guess behind the scenes they need to know this for binding to parameters on the controller action methods. You could then have a tri-state boolean I suppose (bound to a nullable bool parameter). I've not tried it but I'm hoping thats what they did.
You should also use <label for="checkbox1">Checkbox 1</label> because then people can click on the label text as well as the checkbox itself. Its also easier to style and at least in IE it will be highlighted when you tab through the page's controls.
<%= Html.CheckBox("cbNewColors", true) %><label for="cbNewColors">New colors</label>
This is not just a 'oh I could do it' thing. Its a significant user experience enhancement. Even if not all users know they can click on the label many will.
I'm surprised none of these answers used the built in MVC features for this.
I wrote a blog post about this here, which even actually links the labels to the checkbox. I used the EditorTemplate folder to accomplish this in a clean and modular way.
You will simply end up with a new file in the EditorTemplate folder that looks like this:
#model SampleObject
#Html.CheckBoxFor(m => m.IsChecked)
#Html.HiddenFor(m => m.Id)
#Html.LabelFor(m => m.IsChecked, Model.Id)
in your actual view, there will be no need to loop this, simply 1 line of code:
#Html.EditorFor(x => ViewData.Model)
Visit my blog post for more details.
Here's what I've been doing.
View:
<input type="checkbox" name="applyChanges" />
Controller:
var checkBox = Request.Form["applyChanges"];
if (checkBox == "on")
{
...
}
I found the Html.* helper methods not so useful in some cases, and that I was better off doing it in plain old HTML. This being one of them, the other one that comes to mind is radio buttons.
Edit: this is on Preview 5, obviously YMMV between versions.
They appear to be opting to read the first value only, so this is "true" when the checkbox is checked, and "false" when only the hidden value is included. This is easily fetched with code like this:
model.Property = collection["ElementId"].ToLower().StartsWith("true");
#Dylan Beattie Great Find!!! I Thank you much. To expand even further, this technique also works perfect with the View Model approach. MVC is so cool, it's smart enough to bind an array of Guids to a property by the same name of the Model object bound to the View. Example:
ViewModel:
public class SampleViewModel
{
public IList<SampleObject> SampleObjectList { get; set; }
public Guid[] SelectedObjectIds { get; set; }
public class SampleObject
{
public Guid Id { get; set; }
public string Name { get; set; }
}
}
View:
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
<h2>Sample View</h2>
<table>
<thead>
<tr>
<th>Checked</th>
<th>Object Name</th>
</tr>
</thead>
<% using (Html.BeginForm()) %>
<%{%>
<tbody>
<% foreach (var item in Model.SampleObjectList)
{ %>
<tr>
<td><input type="checkbox" name="SelectedObjectIds" value="<%= item.Id%>" /></td>
<td><%= Html.Encode(item.Name)%></td>
</tr>
<% } %>
</tbody>
</table>
<input type="submit" value="Submit" />
<%}%>
Controller:
[AcceptVerbs(HttpVerbs.Get)]
public ActionResult SampleView(Guid id)
{
//Object to pass any input objects to the View Model Builder
BuilderIO viewModelBuilderInput = new BuilderIO();
//The View Model Builder is a conglomerate of repositories and methods used to Construct a View Model out of Business Objects
SampleViewModel viewModel = sampleViewModelBuilder.Build(viewModelBuilderInput);
return View("SampleView", viewModel);
}
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult SampleView(SampleViewModel viewModel)
{
// The array of Guids successfully bound to the SelectedObjectIds property of the View Model!
return View();
}
Anyone familiar with the View Model philosophy will rejoice, this works like a Champ!
I'd also like to point out that you can name each checkbox a different name, and have that name part of the actionresults parameters.
Example,
View:
<%= Html.CheckBox("Rs232CheckBox", false, new { #id = "rs232" })%>RS-232
<%= Html.CheckBox("Rs422CheckBox", false, new { #id = "rs422" })%>RS-422
Controller:
public ActionResults MyAction(bool Rs232CheckBox, bool Rs422CheckBox) {
...
}
The values from the view are passed to the action since the names are the same.
I know this solution isn't ideal for your project, but I thought I'd throw the idea out there.
<input type = "checkbox" name = "checkbox1" /> <label> Check to say hi.</label>
From the Controller:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Index(FormCollection fc)
{
var s = fc["checkbox1"];
if (s == "on")
{
string x = "Hi";
}
}
This issue is happening in the release 1.0 as well. Html.Checkbox() causes another hidden field to be added with the same name/id as of your original checkbox. And as I was trying loading up a checkbox array using document.GetElemtentsByName(), you can guess how things were getting messed up. It's a bizarre.
From what I can gather, the model doesn't want to guess whether checked = true or false, I got around this by setting a value attribute on the checkbox element with jQuery before submitting the form like this:
$('input[type="checkbox"]').each(function () {
$(this).attr('value', $(this).is(':checked'));
});
This way, you don't need a hidden element just to store the value of the checkbox.
I know that this question was written when MVC3 wasn't out, but for anyone who comes to this question and are using MVC3, you may want the "correct" way to do this.
While I think that doing the whole
Contains("true");
thing is great and clean, and works on all MVC versions, the problem is that it doesn't take culture into account (as if it really matters in the case of a bool).
The "correct" way to figure out the value of a bool, at least in MVC3, is to use the ValueProvider.
var value = (bool)ValueProvider.GetValue("key").ConvertTo(typeof(bool));
I do this in one of my client's sites when I edit permissions:
var allPermissionsBase = Request.Params.AllKeys.Where(x => x.Contains("permission_")).ToList();
var allPermissions = new List<KeyValuePair<int, bool>>();
foreach (var key in allPermissionsBase)
{
// Try to parse the key as int
int keyAsInt;
int.TryParse(key.Replace("permission_", ""), out keyAsInt);
// Try to get the value as bool
var value = (bool)ValueProvider.GetValue(key).ConvertTo(typeof(bool));
}
Now, the beauty of this is you can use this with just about any simple type, and it will even be correct based on the Culture (think money, decimals, etc).
The ValueProvider is what is used when you form your Actions like this:
public ActionResult UpdatePermissions(bool permission_1, bool permission_2)
but when you are trying to dynamically build these lists and check the values, you will never know the Id at compile time, so you have to process them on the fly.
The easiest way to do is so...
You set the name and value.
<input type="checkbox" name="selectedProducts" value="#item.ProductId" />#item.Name
Then on submitting grab the values of checkboxes and save in an int array.
then the appropriate LinQ Function. That's it..
[HttpPost]
public ActionResult Checkbox(int[] selectedObjects)
{
var selected = from x in selectedObjects
from y in db
where y.ObjectId == x
select y;
return View(selected);
}
Same as nautic20's answer, just simply use MVC default model binding checkbox list with same name as a collection property of string/int/enum in ViewModel. That is it.
But one issue need to point out. In each checkbox component, you should not put "Id" in it which will affect MVC model binding.
Following code will work for model binding:
<% foreach (var item in Model.SampleObjectList)
{ %>
<tr>
<td><input type="checkbox" name="SelectedObjectIds" value="<%= item.Id%>" /></td>
<td><%= Html.Encode(item.Name)%></td>
</tr>
<% } %>
Following codes will not binding to model (difference here is it assigned id for each checkbox)
<% foreach (var item in Model.SampleObjectList)
{ %>
<tr>
<td><input type="checkbox" name="SelectedObjectIds" id="[some unique key]" value="<%= item.Id%>" /></td>
<td><%= Html.Encode(item.Name)%></td>
</tr>
<% } %>
this is what i did to loose the double values when using the Html.CheckBox(...
Replace("true,false","true").Split(',')
with 4 boxes checked, unchecked, unchecked, checked it turns
true,false,false,false,true,false
into
true,false,false,true.
just what i needed
How about something like this?
bool isChecked = false;
if (Boolean.TryParse(Request.Form.GetValues(”chkHuman”)[0], out isChecked) == false)
ModelState.AddModelError(”chkHuman”, “Nice try.”);
When using the checkbox HtmlHelper, I much prefer to work with the posted checkbox form data as an array. I don't really know why, I know the other methods work, but I think I just prefer to treat comma separated strings as an array as much as possible.
So doing a 'checked' or true test would be:
//looking for [true],[false]
bool isChecked = form.GetValues(key).Contains("true");
Doing a false check would be:
//looking for [false],[false] or [false]
bool isNotChecked = !form.GetValues(key).Contains("true");
The main difference is to use GetValues as this returns as an array.
Just do this on $(document).ready :
$('input:hidden').each(function(el) {
var that = $(this)[0];
if(that.id.length < 1 ) {
console.log(that.id);
that.parentElement.removeChild(that);
}
});
My solution is:
<input type="checkbox" id="IsNew-checkbox" checked="checked" />
<input type="hidden" id="IsNew" name="IsNew" value="true" />
<script language="javascript" type="text/javascript" >
$('#IsNew-checkbox').click(function () {
if ($('#IsNew-checkbox').is(':checked')) {
$('#IsNew').val('true');
} else {
$('#IsNew').val('false');
}
});
</script>
More you can find here:
http://www.blog.mieten.pl/2010/12/asp-net-mvc-custom-checkbox-as-solution-of-string-was-not-recognized-as-a-valid-boolean/
I had nearly the same Problem but the return Value of my Controller was blocked with other Values.
Found a simple Solution but it seems a bit rough.
Try to type Viewbag. in your Controller and now you give it a name like Viewbag.Checkbool
Now switch to the View and try this #Viewbag.Checkbool with this you will get the value out of the Controller.
My Controller Parameters look like this:
public ActionResult Anzeigen(int productid = 90, bool islive = true)
and my Checkbox will update like this:
<input id="isLive" type="checkbox" checked="#ViewBag.Value" ONCLICK="window.location.href = '/MixCategory/Anzeigen?isLive=' + isLive.checked.toString()" />
Using #mmacaulay , I came up with this for bool:
// MVC Work around for checkboxes.
bool active = (Request.Form["active"] == "on");
If checked
active = true
If unchecked
active = false