I would like to bind a complex object to a view.
I create a custom ModelBinder inherited from DefaultModelBinder so if I post the form I can reach proper data in Controller.
But if I want to send data to the view the data will not be binded.
Which method of DefaultModelBinder should I override?
Or anybody knows the solution?
l.
The model binder is not used in the view. It is only used to bind request values to action parameters. HTML helpers are used in the view to generate input fields. So it is those html helpers that might need to be customized to show the proper data from your model.
Related
I would like to set values for the ViewBag in a custom class I have created to handle my viewstate (for want of a non WebForms word!). I am aware that ViewData is a property of Controller base. Is there a way I can access the ViewBag from my class? .. another thought, as I want to do this in a class which is being auto-generated by the model binderr, is it possible to accomplish this by implementing a custom binder?
Regards.
In our asp.net mvc I've created view with two partial views inside.
That view accepts model of some type, for example Customer.
First partial view doesn't have model because it is search form with empty field.
Second form is form with populated fields.
What I found out that on first view, if I have called input fields like properties in model and if I don't provide value for them, mvc implicitly binds values from model to the fields.
First I was thinking is some of kind of mistake, but then I've expiremented little bit with a code:
-I've added native input element with id and name called the same like model, input field is empty in browser
-If I try the same thing with Html.TextBox helper and don't provide value, mvc gets that value from my model object(by name of property/field) and in browser that field is populated.
Is this a bug or am I doing something wrong?
Thanx
That's by design.
I'd recomend reading:
http://asp.net/mvc
http://weblogs.asp.net/scottgu/archive/tags/MVC/default.aspx
and last but not least:
http://channel9.msdn.com/Events/MIX
especially mix10 has a tonn of sessions about mvc
all are good read and watch (-:
That is by design. If you send a model to a view and you're using the HTML input Helpers that come with ASP.NET MVC, they'll implicitly populate themselves from the model.
This is helpful in many situations. If you don't want this behavior, you can always NOT use the helpers or write your own simple helpers.
I have a model with a property that points to a file that contains HTML. My strongly typed view to this model uses a custom HTML helper method to resolve and return the HTML from the file. Works great so far.
The HTML read from each file will contain various controls whose values I need to retrieve when the form is POSTed.
What would be the best way to have access to the POSTed control values in my controller method?
I would prefer a non jQuery solution, but I am not sure if the MVC framework can provide these values to me? Can it provide a list of key/value pairs to the controller somehow?
You could use the FormCollection in ASP.NET MVC.
public ActionResult SomeAction(FormCollection form) {
...
}
You have essentially two options.
1) Use the old fashioned Request variables as all we have done in ASP.NET web forms.
For example in your controller action method you can retrieve any value present on the form with the following method
public ActionResult SomeAction() {
var request = this.ControllerContext.HttpContext.Request;
bool boolParam = bool.Parse( request["boolParam"] ?? "false" );
}
2) Create a custom Model Binder to let the framework pack those values in a custom class object.
This method would be a little bit more difficult at the beginning because you have to create a custom Model Binder but it favour readability on your controller code. For further details on creating custom model binders give a look at the following links (you can find more with a simple search)
Custom Model Binder for Complex composite objects
Custom Model Binder and More UI Validation in ASP.NET MVC
A Custom ASP.NET MVC Model Binder for Repositories
Hope it helps
Is the content of the HTML files dynamic or known at design time? If you know it now, you could have each one post to it's own action and then strongly type the parameters.
So like the title says, I created a view model in my asp.net mvc application so it would be strongly typed to my view. My view model is a combination of two of my model classes. Now when the user hits the save button on that view, it goes to a controller. How does it know what controller to go to? I built my controller 1 - 1 so to speak with my models and views so controller A knows about Model A and controller B knows about Model B. But if I have a view model that is AB how does it know on subit to go to A or B. Do I need a controller called AB Controller?
The controller and action invoked do not depend on the viewmodel object you used to bind the page during initial view rendering. The controller (and action) invoked is determined by the URL of the request sent. (One of the routes you have defined will be matched based on the URL string of the request or a 404 not found error will be returned.)
A submit button in an HTML form (usually a POST) will have an action attribute that determines its url target, an anchor tag will have an href, etc.
In your situation where you have a custom viewmodel object you can define an action to expect and to attempt to parse that specific type of object by specifying it as the parameter to your action:
public ActionResult SaveSystemSetting(SystemAdminVM item) {
An Action Method doesn't receive a model. It receives parameters.
Anyway I think I know where you come from: One of the parameters of your action has the type of the ViewModel used in the View. That is a common layout and makes a lot of sense. In lots of projects it is so widely used that after some time you start to think that an action actually receives a model.
Just remenber that the parameters of your action can by anything that can by filled by the ModelBinder. You could pass both Models as parameters, you could pass a ViewModel that agregates Model a and b or you could pass a ViewModel that has properties of a + b.
Agregation ist the most common approach.
Generally we overload our action methods in the controller so if you have an action called edit that renders the view with your viewmodel object, you will have an overloaded edit action method with the HttpPost specified for that method.
The data to this method will be passed as form value collection values or you can bind it to your viewmodel object if you like and process it further.
If I am passing an XElement or XDocument to my ASP.NET MVC view, what's the best (read: easiest) way to repopulate my XML with the values returned from the edit form on submit?
Thanks,
Matt.
Typically you want a strongly typed model coming into an action, but if you have a good reason to take in XML, then here is the approach I would take:
Create a custom ModelBinder that will do the work for you. In the ModelBinder you can loop through the form and get everything that was submitted and create your XElement. In the global.asax you can specify that you want to use that ModelBinder whenever you have a type of XElement or XDocument.