My model does not really represent what my form is posting. Example my Orgs Model which holds orgs helps me generate a treeview the users selects several nodes of the orgs tree and submits a form. The form posts an array[] or org ids.
(maybe i'm doing this all wrong, please let me know tried binding to models and that was confusing when dealing with trees grids etc and using partial views and ajax returning partial views and editorfor's etc.. the default model binding was useless)
anyways back to my point, since I want to validate if any orgs get selected:
if (SelectedOrgs == null) //array[]
{
ModelState.AddModelError("OrgsNotSelected",IValidationErrors.OrgsNotSelected);
}
my question is how do i retrieve this random key that i just made up from my view? my model and even my viewmodel do not have an array for the selection this is just the result of the post.
I'm not sure what to do in the view to get the value for "OrgsNotSelected".
Thank you!
Bilal
If you were doing normal submit actions to your controller, you would need to use the ValidationSummary to display errors that are not attached to a specific property.
As you are using Ajax, you would be better off returning a json result from your controller and you can define this so that it includes your errors in a format you can use in the success function to display your messages.
Related
My website is built around tabs. I have one single page with multiple partial views that display each tab.
The problem im facing now is I want to loop through files that the user has uploaded and display them in one of my partial views. This requires me to send the file list as a paramater in my action like this:
//Uploadedfiles is a function that adds the files to a list.
var files = UploadedFiles();
return View(files);
Because im only using one view to display all my partial views, i get:
The model item passed into the dictionary is of type 'Microsoft.WindowsAzure.Storage.Core.Util.CommonUtility+d__0`1[Delamapp.CloudStorageServices.UploadEntity]', but this dictionary requires a model item of type 'Delamapp.Models.LoginFolder'.
This means im required to not send a model item to my index view. Now, the only thing i can think off is adding my file list to viewbag and then display them on my view. BUT.. The files require high security. How safe is viewbag? Can you for example store sensitive login information in there? Can you think off some other way to accomplish this?
Thank you in advance
You can pass a model item to your view, but the model item you are passing doesn't match the type of model that your view uses (that's what the error message says).
So you need to do one of the following:
Modify your view to accept the model type that you are passing to it
Put the data you want to pass into the model type that your view is expecting
Create a new model type for both your data and for the view, and use that
In terms of security, I don't think using a view bag versus model binding really enters into the question of security. Both are just ways of passing data in between the controller and the view, and that all takes place within the ASP.NET process (perhaps you have ViewBag confused with Web Forms' ViewState?).
I've understood that a viewmodel in MVC is supposed to reflect data on a single page rather than objects in the model. But should the viewmodel correspond to the data you want to show on that page or to the data you want back from that page? If we for example look at a login page then I just want username and password back in the post, but I might need more variables than that when displaying the login page (previous error messages etc).
Should the viewmodel then just contain username and password as parameters and the rest of the variables end up in viewbags. Or should the viewmodel contain all values I want to show even though I'm only interested in a few of them in the response.
What is best practice when using viewmodels?
All data that somehow interacts between the html and your server should be in a ViewModel.
This allows you to perform formatting and such outside your html and inside your ViewModel properties.
However, if your page contains a lot of controls or data, you may want to split it into multiple ViewModels (example one for the Get and one for the Post).
The post model may contain only data that you entered and needs to be validated.
I think it's best to put everything in the view-model. This keeps the code cleaner and makes discovery and maintenance easier as well. The view-model should be your primary mechanism here.
I would say only properties you need, in your case username and password. If you want to display error messages then that's what ModelState is for. You can always append any error messages to your ModelState:
ModelState.AddModelError("PropertyName", "Error Text")
Beyond that let's say you have a form that contains a list of categories that you need to pick one category from a drop down. In this case I usually attach that list to my model even though the only thing being submitted is the actual selected value. But this is a matter of preference, meaning I could also set a ViewBag to contain this SelectList of categories and then bind that to your DropDownList. I suppose it's better to place this in a model because ViewBag is dynamic and you will have to cast anything in the ViewBag into it's underlying type on your views.
I have an asp mvc 2 app lication where I want to display a list of check boxes that a user can select, based on a list of records in a database. To display the list my model contains a List object and the view has a foreach, and outputs Html.CheckBox for each item in the list.
Is there a way to get the model populated with the selected checkboxes, given that the model can't have specific properties for each checkbox, because the list is dynamic? Or do I have to manually iterate through the forms variables myself?
Edit: Extra details as per sabanito's comment
So in a simple view/model scenario, if my model had a property called Property1, then my view outputted a Textbox for Property1, when the form is posted via a submit button, the mvc framework will automatically populate a model with Property1 containing the text that was entered into the textbox and pass that model to the Controllers action.
Because I am dealing with a dynamic list of options the user could check, I can't write explicit boolean properties in my model and explicitly create the checkboxes in my view. Given that my list is dynamic, I'm wondering if there are ways to create my model and view so that the mvc framework is able to populate the model correctly when the form is posted.
Here's what I would do:
Are you having any issues generating the checkbox's dynamically?
If not, create a property on your ViewModel that is a:
public List<string> CheckboxResults { get; set; }
When you generate your checkbox's in the view make sure they all share the name = "CheckboxResults". When MVC see's your ViewModel as a parameter on the action method it will automatically bind and put all the "CheckboxResults" results in the List (as well as your other ViewModel properties). Now you have a dynamic List based on which checkbox's your user checked that you can send to your DomainModel or wherever.
Pretty cool stuff. Let me know if you're having issues generating the checkbox's dynamically, that's kind of a seperate issue than model binding to a list.
Use a ViewModel that reflects your view exactly, and map your domain model(s) to the viewmodel.
At first it often seems appropriate to use domain models directly in the view, for no better reason than that they're simple to use. However, as the view gets more complex over time, you end up putting a TON of conditional logic in your view, and end up with spaghetti. To alleviate this, we typically create a ViewModel that correlates 1:1 with the view.
I have the following model:
Customer:
ID
Name
Address
Phone
Fax
I added an Edit view based on the above model from the controller. I modified the Edit view to only allow edit on the Phone and Fax field (deleted the rest). When I submit it I get an error. It works if I leave the Edit view untouched (5 fields). However I only want to allow change in the last 2 fields.
I am lost, please help. Thanks :)
If you are using the MVC ability to populate your entity/class i.e. your action sig looks like this:
ViewResult MyAction(MyObject object) {
...
Save(MyObject);
}
then you'll need to make sure you include the other field, non-editable, either as visible information or using Html.Hidden within the form scope to ensure you have a fully populated object. Remember, the web is stateless and the server has no idea which record you were editing unless it has the keys to do so retrospectively.
The other option would be to retrieve the original object (for which you'll still need the primary key) from the database, update the fields from your form data and then submit the changes. We'd need to know the specific error to be able to help further, the code you are using would also be a great help.
Without knowing more I would guess it has something to do with binding null to a non null property in your model. Can you give me more details on the model, the error.
If you are using the default mvc model binder then it will only bind the fields you submit. So either submit as hidden or dont use a model binder and manually map the variable from Request.Form into a copy of the model you pulled form the db.
I have two forms on one page: a results form and a search form. The search form uses a partial view because it is displayed on several different pages. I want to be able to persist the data in the search form regardles of which button on which form the user clicks. The problem is that when the user clicks on a link or button from the results form, only the form values from the results form are posted, the values from the search form are not included. How can I maintain the values in the search form even when it is not the form that is submitted? I do not want to use any type of session state to maintain the form and I dont want to write the search values in hidden fields in the results form. I just want to be able to post them with the form values of the results form so that the users search criteria can be maintained accross any page that displays the search partial view. What am I missing?
The first thought that occured to me is to remove the form wrapping the search control and just let it be rendered into the form with the results data. I worry here about naming conflicts. What happens when the search from has a control with the same name as the results form, wouldn't this cause a naming conflict? I suppose that this could just be managed manually to ensure that there are unique names whenever rendering partial views into other views, perhaps even going so far as to prefix values with the partial view name, but that reminds me of the ugliness that is INamingContainer in web forms - plus makes for cumbersome field names in your model.
Is there some sort of elegant solution that will allow a form to persist state that I am missing? Thanks!
Normally, I persist the search criteria on the server side when the search is performed. If the user changes the search criteria after performing the search, then posts the form any changes are, of course, lost but that's arguably correct behavior since the search wasn't invoked. This is true whether the search is performed from a full post or via ajax. Handling it this way keeps the actions cleaner, I think as you don't need to handle the search data in the other actions.
If you absolutely need to have the search parameters included, you could consider having the second form post via javascript, pick up the search field values dynamically and add them to the second form (as hidden fields) prior to posting the second form. You wouldn't have to maintain the values in two places in synchronization, but you would have to copy them to the second form before posting.
At the moment i got it like this:
Forms which has search box, posts query (and additional data if needed) to search controller which then renders search view. Search view is made from search box and search results partial views. During this - search box form is reconstructed by posted data.
If i need search results form to perform another search request (for example, with specified page index), it goes through ajax, which posts search box form + page index from search results form. Take a look here for ideas (update that JS method with targetId parameter for updating specified div/form and post additional data if needed here like this:
form.serialize()+"&pageIndex=5"
In short: if you need to maintain state of form + update another in one page - consider using partial updates, otherwise you will end up inventing ViewState 2.0.
One caveat with this way - it's tricky to make search box contain something what is related with search results (i.e. - total count of found items). Before i managed to handle this, our designer did that - i just need to add div with appropriate class name ("sbsubst" or something) and it looks that it's inside search box. :)
When you have few forms at your page each form sends only its own data. In WebForms you had only one form (at least server-side) and each control was included into this form. In ASP.NET MVC you can use the same scenario and I'm afraid you will have to if you want to have the described behavior. Don't forget - partial forms don't have to be real forms. Moreover, RenderPartial is mostly used for "control-like" layout creation.
As for the second part of your question I would suggest naming your text boxes in search form with some normal prefix like "search" or something like that. For instance, if you have text box "text" and "language" in the form, you will have "searchText" and "searchLanguage". These names are quite unique and you will have normal names in your parameters.
I am not suggesting you populating the hidden values in your results form on POST event since you said it's not an option for you but still it may be the only way if you want to have two forms.
I think the best approach will be storing the text from search input when it changes in the query part of your second form action url. For example (not tested):
$('input#yourSearchInput').change(function()
{
var searchText = $(this).val();
// or? var searchText = encodeURIComponent($(this).val());
var secondForm = $('form#secondFormId');
var action = secondForm.attr('action');
var queryStart = action.lastIndexOf('?search=');
if(queryStart > -1) {
action = action.substring(1, queryStart);
}
action = action + "?search=" + searchText;
secondForm.attr('action', action);
});
In Controller (or custom filter):
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
var search = Request.QueryString["search"];
if(!String.IsNullOrEmpty(search)) {
ViewData["SearchFromPOST"] = search;
}
base.OnActionExecuting(filterContext);
}
In your Search Control:
<%= TextBox("yourSearchInputId", ViewData["SearchFromPOST"]) %>