Few basic query about ASP.Net MVC - asp.net-mvc-3

Question

i am new in mvc and learning it by going through wrox book. i encounter few thing and i am looking for good clarification.apologized for asking many question in one shot.
1) #Html.DisplayFor & #Html.EditFor
when we use #Html.DisplayFor then what html control render at client side ?
when we use #Html.EditFor then what html control render at client side ?
2) what ModelState.IsValid does ?
i always see ModelState.IsValid return true ? when it actually return false ?
3) how to extract the form submitted value from ModelState ?
i try to do it this way like ModelState["Name"] or ModelState["Name"].ToString() both gives error.
4) what is Remote Validation in mvc ?
5) when we use html helper to render text boxes then how could i attach multiple attribute with it. i tried this way
i tried to display model text like this way but did not
#Html.LabelFor(m => m.Name, new { #id = "name", #class = "", title = "#m.Name" })
can't we specify or assign model text like this way title = "#m.Name" ? if not then how could i assign a model text to title attribute ?
when we need to use # sign when we work with html controls attribute
6) Is it possible to call different type of function/method directly from view
i like to know that
a) if i have few static function or static classes function then can we call it directly from view ?
b) can we can controller method directly from view ?
c) how to call any generic method directly from view?
d) is it possible to call any action method directly from view ?
e) can we can call any model method directly from view ?
which is possible and which is not please explain with reason and sample code
7) regarding data annotation
i want to work with data annotation but i want data annotation should render different js in page for fancy validation message. how to use different jquery validation plugin with data annotation....where we need to change in code.
please answer all my question point wise with example & sample code for better understanding. thanks

Answer 1

when we use #Html.DisplayFor then what html control render at client side ?
That's totally gonna depend on the specific type of the property you are calling the DisplayFor on. The DisplayFor helper will analyze the specific type of the property used in the expression and invoke the corresponding display template. You could also write custom display templates for your view model types. Brad Wilson wrote a nice blog post about templates that I invite you to go through to better familiarize with the basic concepts: http://bradwilson.typepad.com/blog/2009/10/aspnet-mvc-2-templates-part-1-introduction.html
There are a series of posts, make sure you've read them all.
when we use #Html.EditFor then what html control render at client side ?
That's totally gonna depend on the specific type of the property you are calling the EditorFor on. The EditorFor helper will analyze the specific type of the property used in the expression and invoke the corresponding editor template. You could also write custom editor templates for your view model types. Brad Wilson wrote a nice blog post about templates that I invite you to go through to better familiarize with the basic concepts: http://bradwilson.typepad.com/blog/2009/10/aspnet-mvc-2-templates-part-1-introduction.html
There are a series of posts, make sure you've read them all.
i always see ModelState.IsValid return true ? when it actually return false ?
When there are errors added to the ModelState. Could happen if you have used some data annotations on your view model to do validation and the values submitted to the server failed this validation. Normally it's the default model binder that is adding error messages to the ModelState (making ModelState.IsValid return false) when binding the request values to your view model.
i try to do it this way like ModelState["Name"] or ModelState["Name"].ToString() both gives error.
In ASP.NET MVC you use a view model. Your [HttpPost] controller action takes a view model as parameter which is a class specifically designed to meet the purpose of your view logic. Here's an example of how a typical POST action might look like in ASP.NET MVC:
[HttpPost]
public ActionResult SomeAction(MyViewModel model)
{
if (!ModelState.IsValid)
{
// validation on the view model failed => redisplay the view
// so that the user can fix the errors
return View(model);
}
// At this stage you know that the model has passed validation
// It is here that you would typically map the view model to some domain model(s)
// and pass them to your DAL for some processing.
// Finally when this processing completes redirect (Redirect-After-Get pattern)
return RedirectToAction("Success");
}
4) what is Remote Validation in mvc ?
It's a view model property decorated with the [Remote] attribute which in turn emitted some HTML5 data-* attributes on the corresponding input field. In turn the jquery.validate.unobtrusive.js script will use those properties to send an AJAX request to the corresponding controller action to perform validation before the form is actually submitted. Please feel free to read the corresponding documentation: http://msdn.microsoft.com/en-us/library/gg508808(v=vs.98).aspx
a) if i have few static function or static classes function then can
we call it directly from view ?
No of course not. This question doesn't have any sense. The view doesn't know about any server side specific things other than controller actions. So if you want to call something from a view this something in the ASP.NET MVC world is called a controller action. You could of course us AJAX or something to call it.
b) can we can controller method directly from view ?
Yes, of course, if this controller method returns an ActionResult in which case this controller method has a name: A controller action.
c) how to call any generic method directly from view
Absolutely impossible. That would have been a huge security vulnerability if it was possible. You can only invoke controller actions from a view.
e) can we can call any model method directly from view ?
No, for the Christ sake. I repeat: That would have been a huge seurity vulnerability if it was possible. You can only invoke controller actions from a view.
i want to work with data annotation but i want data annotation should
render different js in page for fancy validation message. how to use
different jquery validation plugin with data annotation....where we
need to change in code.
Sorry, I have strictly no idea what you are asking here. ASP.NET MVC client side validation is tightly coupled with the jquery.validate plugin (whose documentation I invite you to read to better understand its functionality: http://jqueryvalidation.org/documentation/). And if this plugin doesn't meet your requirements, after all, ASP.NET MVC view spits HTML, so feel more than free to use some of the gazillions available javascript validation plugins out there that might fit your specific needs.
Hopefully this answers some of your questions. Next time you post a question on StackOverflow make sure that it is very specific and not asking about the philosophy on the entire world (as you did here). Make your homework, read the documentation, and if you have specific issues, post your code, explain the difficulties you encountered with it, and we will be glad to help.