So I'm new to MVC and ASP.Net. I've been reading through the posts on here all afternoon and I just can't get this to work. I have tried this, this, and this and I just don't know what I'm doing wrong.
Condition Class
public class conditions
{
public string condName;
public bool condValue;
public conditions(string s)
{
condName = s;
}
}
Risk History Class
public class riskHistory
{
public List<conditions> results;
public riskHistory()
{
results = new List<conditions>();
results.Add(new conditions("History of Marfans Syndrome"));
results.Add(new conditions("Family history of aortic disease"));
results.Add(new conditions("Recent aortic manipulation"));
results.Add(new conditions("Known thorasic aorta aneurysm"));
}
}
Now there is a riskPain and riskFeatures class defined the same way. I needed to split this into 3 because each has to be handled differently. What I display over each class unique in the view.
View Model defined as
public class adViewModel
{
public riskFeatures rF;
public riskPain rP;
public riskHistory rH;
public adViewModel()
{
rF = new riskFeatures();
rH = new riskHistory();
rP = new riskPain();
}
}
And then I have this code in the view. It's strongly typed to adViewModel.
Does the patient have any of the following history?
#for (int x =0; x<Model.rH.results.Count; x++)
{
string n = Model.rH.results[x].condName.ToString();
<b>#Html.Label(n)</b> #Html.CheckBoxFor(m => m.rH.results[x].condValue)
}
Does the patient have any of the following features to their pain?
// continue on to the other classes
The view displays correctly but when I submit the form it doesn't bind (all condvalue's are false). If you are going to suggest an editor template then I have a second question. The question in the view code above the for loop "Does the patient have the following history?" that question has to be different for each set of checkboxes. How would that work?
Thanks a ton guys!
~Chad
So, using the Html helpers like CheckBoxFor inside for loops caused problems for me because I didn't have control over the ids of the input tags that were generated. Check the final markup that is rendered and see what the ids of the controls it is making are. Writing out the html for the controls isn't really that much longer then calling the helper method anyway.
Related
I am trying to have a general home page that depending on the parameter passed to the control, different content (modules) will be displayed.
For example, a user may select Kentucky from the menu and the id for Kentucky is 1. The home controller gets the id (1) and determines the possible modules for that
state (a simple db call.) Perhaps there is an announcements module and a contacts module for the state. An announcements module could have several items but it's only one module. There would be a partial view for each type of module.
Here is the basic setup I have.
public interface IModuleRepository
{
IList<MenuItemModule> GetMenuItemModules(int menuItem);
IList<Announcements> GetAnnouncements(int modID);
IList<News> GetNews(int modID);
IList<Contacts> GetContacts(int modID);
}
//business object
public class MenuItemModule
{
private int _MenuItemID;
private int _ModuleID;
private int _ModuleDefID;
private string _Src;
private int _ModuleOrder;
//get, set properties for these...
}
//announcements entity
public class Announcements
{
private int _ID = -1;
private int _MenuItemID = -1;
private int _ModuleID = -1;
private string _Description = string.Empty;
//get set props ...
}
In my home controller...
public class HomeController : Controller
{
private IModuleRepository modRepository;
public HomeController(IModuleRepository modRepository)
{
this.modRepository = modRepository;
}
public ViewResult Item(string ItemID)
{
//returns a list of menuitemmodules for the page. This gives me the Src or name of each
//module on the page, i.e. Announcements, news, contacts, etc.
var modules = modRepository.GetMenuItemModules(Convert.ToInt32(ItemID));
return View(modules);
}
}
I have tried several different models to return but I always run up against some contstraint. If I pass the menuitemmodules to my Item.aspx, then I can do something like this:
foreach (var mod in Model)
{
Html.RenderPartial(mod.Src, a); //needs an announcement object though
}
That makes it somewhat dynamic because I have the Src which would basically be something like "Announcements" and I can just create an announcements.ascx partial to process the module. But I have found it difficult to pass my menuitemmodule and an announcements entity as well.
I have also messed around with passing a more complex object and then testing every Src that comes through with an If statement. This would make scaling difficult in the future as I increase the number of possible modules in the app.
How can I solve my problem? I hope I have provided enough info. I like the basic idea here - http://www.mikesdotnetting.com/Article/105/ASP.NET-MVC-Partial-Views-and-Strongly-Typed-Custom-ViewModels but that seems to only work for static modules on a page.
I did try a composite view model called ModuleViewModel. Here is that attempt:
public class ModuleViewModel
{
public IList<Announcements> announcements { get; set; }
public IList<MenuItemModule> mods { get; set; }
}
If I pass that model to the Item.aspx I can do something like this (but I must be doing something wrong because something doesn't look right.)
foreach (var mod in Model)
{
if (mod.announcements.Count > 0)
{
Html.RenderPartial("Announcements", mod.announcements);
}
}
Once again, scalability is going to haunt me. I would like to have something like this on item page:
foreach (var mod in Model)
{
Html.RenderPartial(mod.Src, mod);
}
That would the correct partial view and pass it the correct model.
Create Module classes that derive from a common Module base class:
public class AnnouncementsModule : Module
{
}
public class ContactsModule : Module
{
}
In controller:
Create your various modules and put them into your overall view module (here it has a property called Modules that is an array of Module:
var viewModel = new ComplexViewModel
{
Modules = new []
{
new ContactsModule(),
new AnnouncementsModule()
}
};
return View(viewModule);
In view:
#Html.DisplayFor(x => x.Modules);
Create the partial views for each Type of Module in the appropriate 'Shared` folder. (Run it without creating them and it will show you an exception with the locations where it's looking for them).
After messing around with this for over a week, I finally managed to figure out how MVC can do what I want dynamically. I decided to post my solution for others that are new to MVC. Hopefully, the following will clear up the misunderstandings I had (although, at this point in my understanding of MVC, I cannot say this is the best approach.)
I will include the previous code snips and modifications for clarity:
public interface IModuleRepository
{
IList<MenuItemModule> GetMenuItemModules(int menuItem);
IList<Announcements> GetAnnouncements(int modID);
IList<News> GetNews(int modID);
IList<Contacts> GetContacts(int modID);
}
//business object
public class MenuItemModule
{
private int _MenuItemID;
private int _ModuleID;
private int _ModuleDefID;
private string _Src;
private int _ModuleOrder;
//get, set properties for these...
}
//announcements entity
public class Announcements : MenuItemModule
{
private int _ID = -1;
private string _Description = string.Empty;
//get set props ...
}
I also added another class:
public class AnnouncementModule : MenuItemModule
{
private IList<Announcements> _Announcements;
//get set prop
}
...and I created a model for the view
public class HomeItemViewModel
{
public MenuItemModule[] MenuItemModules { get; set; } //collection of menuitemmodules
}
In my home controller...
var menuItemModules = modRepository.GetMenuItemModules(ItemID);
if (menuItemModules.Count > 0)
{
AnnouncementModule aMod;
MenuItemModule[] mods = new MenuItemModule[menuItemModules.Count()];
int i = 0;
//loop through each MenuItemModule assign to the appropriate model
foreach (MenuItemModule mod in menuItemModules)
{
if (mod.Src == "Announcements")
{
aMod = new AnnouncementModule();
aMod.Announcements = modRepository.GetAnnouncements(mod.ModuleID);
//now add this to the menuitemmodule collection
mods[i] = aMod;
}
if (mod.Src == "Contacts")
{
//...
}
i++;
}
}
var viewModel = new HomeItemViewModel
{
MenuItemModules = mods
};
return View(viewModel);
Then I used the suggestion to use DisplayFor in the view. The view is strongly typed to HomeItemViewModel.
<%: Html.DisplayFor(m => m.MenuItemModules) %>
This iterates through the collection and based on the type, it will call that template. In this example, it calls AnnouncementModule.ascx which is strongly typed to AnnouncementModule.
foreach (var a in Model.Announcements)
{
//a.Description will give us the description of the announcement
}
I realize there are slicker ways to code the controller, and I plan on refactoring, but this skeleton should provide the basics to solve the question I posted.
I have a question.
My question actually extends from this one:
Shortly - what I want to get: 3 models, and 1 super model for this specific view. This super model fills(properly) IENumerable, IENumerable, IENumerable, to use them in View part. (as far as I understand it, at least...)
In this other topic Dan Revell proposed verry nice and elegant solution, but this solution does not fetch data from DB itself...
Question:
What must be done to get data in this model from DB, not from "new" instance constructors?
While using this approach tried to fetch data from DBContext. And got some problems in it ) I can't understand when (or how) to create my DBContext... Or how to access one that is created by application...
Tried to create it forcefully in Controller, like
using (var Db = new thetaskermvc.Models.TaskerDBContext())
{
var themodel = new thetaskermvc.Models.TotalView();
//Jobbers
themodel.Jobberz = new Dictionary<int, thetaskermvc.Models.Jobbers>();
var jobbers = from Jobbers in Db.Jobbers.OrderBy(g => g.jobb_name) select Jobbers;
foreach (Models.Jobbers ad in jobbers)
{
themodel.Jobberz.Add(ad.jobb_id,
new Models.Jobbers(ad.jobb_id, ad.jobb_name, ad.jobb_from, ad.jobb_carma, ad.jobb_status, ad.jobb_balance, ad.jobb_time));
}
if (themodel.Jobberz.Count == 0)
{
themodel.Jobberz.Add(-1, new Models.Jobbers(0, "NOTHING FOUND",DateTime.Now,0,"",0,0));
}
}
But as created that way Context stops it's existence (?) after passing data away from controller - I can't use it any other way but to get all data inside this controller, and fill data in model by direct add into collections in it (while use of IENumerable would fetch data on-demand, as far as I get it).
So.. If it ain't hard please enlighten me about - is it Ok to use such approach, or there is some other "common" way? Becaus beside it's clumsiness - this approach works...
PS I'm quite new to Asp, yet...
I have one view model per view with data from multiple tables (if required). On my view I have data that needs to be loaded from 2 different database tables. In my grant application controller I have the following:
private readonly IBankService bankService;
private readonly IAccountTypeService accountTypeService;
public GrantApplicationController(IBankService bankService, IAccountTypeService accountTypeService)
{
// Check incoming parameters for null values
this.bankService = bankService;
this.accountTypeService = accountTypeService;
}
In my Create action method I populate my banks and account types (to be used in drop downs) like this (different tables):
public ActionResult Create()
{
GrantApplicationCreateViewModel viewModel = new GrantApplicationCreateViewModel
{
Banks = bankService.FindAll(),
AccountTypes = accountTypeService.FindAll()
}
// Do what ever else you need to get done
return View(viewModel);
}
My partial view model would like this:
public class GrantApplicationCreateViewModel
{
public int BankId { get; set; }
public IEnumerable<Bank> Banks { get; set; }
public int AccountTypeId { get; set; }
public IEnumerable<AccountType> AccountTypes { get; set; }
// Other properties
}
In my repository class I would use the database context like this (I use Entity Framework code first):
public class BankRepository : IBankRepository
{
HefContext db = new HefContext
public IEnumerable<Bank> FindAll()
{
return db.Banks.OrderBy(x => x.Name);
}
}
In my database context class:
public class HefContext : DbContext
{
public DbSet<Bank> Banks { get; set; }
public DbSet<AccountType> AccountTypes { get; set; }
}
Doing it this way you can have one view model that has data from multiple sources. I hope this answers your question? If you need more explanation please let me know :)
You may want to have a look at this post, it explains (with a sample project) how an ideal MVC application architecture should be.
In your code sample above, your shouldn't have any references to DbContexts in a controller. Controller's job is to control the flow of requests not to connect to the DB and perform Model population.
I have finally gotten over one hurdle and can now successfully create new model data. Now there's another catch - validation. Most of the validation seems easy enough as a lot of my model data are scalar values. There is a many-to-many relationship I link to, however, so I'm not sure how to go about validating that. My model is (once again):
Game (only listing the relevant columns):
GameID - int (primary key, auto-incr)
Platform:
PlatformID - int (primary key, auto-incr)
Name - string
GamePlatform (not a visible entity):
GameID - int (foreign key from Games)
PlatformID - int (foreign key from Platforms)
And my Create method (yes, I know it's sloppy and amateurish - I am an amateur and trying to learn. I'll definitely add error checking to it. I'm just trying to get the big picture of the view->controller->validation->persist-in-db/show errors process down):
public ActionResult CreateReview([Bind(prefix = "GameData")]Game newGame, int[] PlatformIDs)
{
try
{
foreach(int i in PlatformIDs)
{
Platform plat = _siteDB.Platforms.Single(p => p.PlatformID == i);
newGame.Platforms.Add(plat);
}
newGame.LastModified = Datetime.Now;
_siteDB.Games.AddObject(newGame);
_siteDB.SaveChanges();
return RedirectToAction("Index");
}
catch
{
return View();
}
}
The array of PlatformIDs are supplied by a group of checkboxes within my view. For my Game to be valid, it must be associated with at least one Platform. I'm just not sure how to validate that with data annotations, or if it's even possible to do so. Any help would be greatly appreciated.
If I understand your question correctly, your int[] potentially contains ints associated with the ID of a Platform in your DB and you want to make sure your int[] contains at least one valid PlatformID, correct?
Immediately you could do just a simple check prior to going into your logic:
// If there aren't any IDs in Platform that are in PlatformIDs...
if (!_siteDB.Platforms.Any(p => PlatformIDs.Contains(p.PlatformID)))
Return RedirectToAction("Index");
// And probably tell the user to check a box, if they did,
// One of your checkboxes isn't matching up with your PlatformIDs
Ideally what you'd want to do is add the int[] to your model so you can check model validation. Since databased don't typically store int[], add it to your Game model. The EF probably put your DB Entities in your Models folder and if you look at them, you'll see they're partial classes. So add this in your Models folder:
public partial class Game
{
public Dictionary<int, bool> SupportedPlatforms { get; set; }// Edited
}
// Also add this which you'll see why below
public partial class Platform
{
public static bool IsValidPlatformID(int PlatformID)
{
using (SiteDBEntities _siteDB = new SiteDBEntities())
return _siteDB.Platforms.Any(p => p.PlatformID.Equals(PlatformID));
}
}
Then add a custom ValidationAttribute class:
public ContainsValidPlatformIDAttribute : ValidationAttribute
{
public ContainsValidPlatformIDAttribute() { }
public override bool IsValid(object value)
{
Dictionary<int, bool> supportedPlatforms = (Dictionary<int, bool>)value;
if (value == null)
return true;
foreach (int i in values)
{
if (supportedPlatforms.Values.Any(b => b.Equals(true)))// Edited
return false;
}
return true;
}
Now decorate your Property with it in the Game class:
[ContainsValidPlatformID(Error = "You did not select a valid Platform.")]
public Dictionary<int, bool> SupportedPlatforms { get; set; }// Edited
(Edited)Now instead of hard coding a checkbox for each platform, add this instead:
<%: Html.CheckboxFor(model => model.SupportedPlatforms[0]) %>
<%: Html.ValidationMessageFor(model => model.SupportedPlatforms[0]) %>
(Edited)Now your checkboxes are tied to the Model, you can validate the model in the controller, and you can remove the int[] argument from your Action method. This has all been coded from my head into this editor so you may need to tweak some things here and there but this is the direction you should be heading in when working with Models in Views.
Also, check out what Scott Guthrie has written on the topic of MVC Model Validation in his blog. Hopefully with my sample and Scott's blog, you'll be pointed in the right direction.
Hey there! I'm relatively new to both GWT and java programming (or OOP for that matter), so apologies for the beginner questions/mistakes in advance. I've been trying to create some kind of observer pattern, but the development mode console keeps dropping error messages and sadly, they're far from helpful.
So here's what I'm trying to achieve:
- I've got the model that consists of the class Country, and stores a value called Influence.
- The view is the class called CountryDisplay. It's a GWT widget that should always display the current influence of a given country.
public class Country {
private int influece;
private CountryDisplay display;
public Country() {
influence = 0;
}
public void setDisplay(CountryDisplay display) //...
public int getInfluence() //...
public void setInfluence(int value) {
influence = value;
display.update();
}
}
public class CountryDisplay {
private Country country;
public CountryDisplay (Country country) {
//GWT widget creating stuff
this.country = country;
}
public void update() {
//InfluenceCounter is a simple Label
InfluenceCounter.setText(Integer.toString(country.getInfluence()));
}
}
Then in the EntryPoint class I do something like this:
Country italy = new Country();
CountryDisplay italyDisplay = new CountryDisplay(italy);
italy.setDisplay(italyDisplay);
RootPanel.get("nameFieldContainer").add(italyDisplay);
italy.setInfluence(3);
The development console indicated that it had a problem with the line "display.update();" in class Country. My first guess was that the problem was that the display was not initiated, so I created an interface for it, and in the Country constructor I created an empty, new display, that would later be overwritten.
public Country() {
influence = 0;
display = new DisplayInterface() {
public void update() {}
}
}
But I had no luck this way either. I guess this kind of cross-referencing is not allowed? I mean that the view has the model as a variable and vice versa.
When calling a method on the view individually (like:
italy.setInfluence(3);
italyDisplay.displayTheCurrentValue();
) it works, so the problem is definitely in the observer logic.
If I understand correctly, your are trying to "bind" user interface elements (your view class CountryDisplay) to data (the model class Country). "Bind" in the sense that if you change the model data (for example, call italy.setInfluence(10)) then the view would automatically update itself to reflect the change. And if your view provided an editor, you want the "binding" also to work in the other direction.
There are several frameworks out there that achieve this, see for example the post Best data binding solution for GWT. I have used GWT Pectin and there is the GWT Editors framework (which I have not yet used myself as it is relatively new).
Looking at your code, I feel you might want to more clearly separate the model from the view: your model class (Country) should not know about the view class, that is, it should not store a reference to CountryDisplay.
i'm trying to wrap my head around how to enterprise up my code: taking a simple routine and splitting it up into 5 or 6 methods in 3 or 4 classes.
i quickly came up three simple examples of code how i currently write it. Could someone please convert these into an MVC/MVP obfuscated version?
Example 1: The last name is mandatory. Color the text box red if nothing is entered. Color it green if stuff is entered:
private void txtLastname_TextChanged(object sender, EventArgs e)
{
//Lastname mandatory.
//Color pinkish if nothing entered. Greenish if entered.
if (txtLastname.Text.Trim() == "")
{
//Lastname is required, color pinkish
txtLastname.BackColor = ControlBad;
}
else
{
//Lastname entered, remove the coloring
txtLastname.BackColor = ControlGood;
}
}
Example 2: The first name is optional, but try to get it. We'll add a bluish tint to this "try to get" field:
private void txtFirstname_TextChanged(object sender, EventArgs e)
{
//Firstname can be blank.
//Hint them that they should *try* to get it with a bluish color.
//If they do enter stuff: it better be not all spaces.
if (txtFirstname.Text == "")
{
//Nothing there, hint it blue
txtFirstname.BackColor = ControlRequired;
}
else if (txtFirstname.Text.Trim() == "")
{
//They entered spaces - bad user!
txtFirstname.BackColor = ControlBad;
}
else
{
//Entered stuff, remove coloring
txtFirstname.BackColor = SystemColors.Window;
}
}
Example 3 The age is totally optional. If an age is entered, it better be valid:
private void txtAge_TextChanged(object sender, EventArgs e)
{
//Age is optional, but if entered it better be valid
int nAge = 0;
if (Int32.TryParse(txtAge.Text, out nAge))
{
//Valid integer entered
if (nAge < 0)
{
//Negative age? i don't think so
txtAge.BackColor = ControlBad;
}
else
{
//Valid age entered, remove coloring
txtAge.BackColor = SystemColors.Window;
}
}
else
{
//Whatever is in there: it's *not* a valid integer,
if (txtAge.Text == "")
{
//Blank is okay
txtAge.BackColor = SystemColors.Window;
}
else
{
//Not a valid age, bad user
txtAge.BackColor = ControlBad;
}
}
}
Every time i see MVC code, it looks almost like random splitting of code into different methods, classes, and files. i've not been able to determine a reason or pattern to their madness. Without any understanding of they why it's being one some way, it makes no sense. And using the words model, view, controller and presenter, like i'm supposed to know what that means, doesn't help.
The model is your data.
The view shows data on screen.
The controller is used to carry out
the users actions
And oranges taste orangy.
Here's my attempt at splitting things up in order to make the code more difficult to follow. Is this anywhere close to MVC?
private void txtFirstname_TextChanged(object sender, EventArgs e)
{
FirstnameTextChangedHandler(sender, e);
}
private void FirstnameTextChangedHandler(sender, e)
{
string firstname = GetFirstname();
Color firstnameTextBoxColor = GetFirstnameTextBoxColor(firstname);
SetFirstNameTextBoxColor(firstnameTextBoxColor);
}
private string GetFirstname()
{
return txtFirstname.Text;
}
private Color GetFirstnameTextBoxColor(string firstname)
{
//Firstname can be blank.
//Hint them that they should *try* to get it with a bluish color.
//If they do enter stuff: it better be not all spaces.
if (firstname == "")
{
//Nothing there, hint it blue
return GetControlRequiredColor();
}
else if (firstname.Trim() == "")
{
//They entered spaces - bad user!
return GetControlBadColor();
}
else
{
//Entered stuff, remove coloring
return GetControlDefaultColor();
}
}
private Color GetControlRequiredColor()
{
return ControlRequired;
}
private Color GetControlBadColor()
{
return ControlBad;
}
private Color GetControlGoodColor()
{
return ControlGood;
}
//am i doin it rite
i've obfuscated the code, but it's still altogether. The next step in the MVC obfuscation, i gather, is to hide the code in 3 or 4 different files.
It's that next step that i don't understand. What is the logical separation of which functions are moved into what other classes? Can someone translate my 3 simple examples above into full fledged MVC obfuscation?
Edit: Not ASP/ASP.NET/Online. Pretend it's on a desktop, handheld, surface, kiosk. And pretend it's language agnostic.
The purpose of MVC/MVP patterns is not obfuscation, but separation of concerns. Obfuscation is to (conceal the) intended meaning in communication, making communication confusing, intentionally ambiguous, and more difficult to interpret: ref. The use of patterns is to make the code cleaner and more understandable. I suggest you start out by reading the wikipedia entries on MVC and MVP.
Both patterns are ways of structuring your code so that your application is broken up into elements that carry out specific purposes that have clearly defined interaction boundaries. Rather than having code that specifically addresses business concerns, input/output handling, and presentation throughout the various classes of the application, these concerns are separated and isolated in the various architectural components. These architectural elements are insulated from one another by the interaction boundaries (interfaces) making them more independent of one another and easier to modify without affect the application as a whole.
The main idea I have when implementing MVC for Windows Forms is that I want to have unit tests for my model and my controller. In order to achieve that, my controller should not know anything about the views using it, and so any notifications that should be handled on UI level are implemented as events. In your example, my controller would look something like this:
class Controller
{
// This is the model we are operating on
private Model model_;
public enum Status
{
Normal,
Required,
Good,
Bad
}
public delegate void FirstNameStatusChangedDelegate(Status newStatus);
public event FirstNameStatusChangedDelegate FirstNameStatusChangedEvent;
public string FirstName
{
get { return model_.FirstName; }
set
{
if (value == "")
RaiseFirstNameStatusChanged(Status.Required);
else if ( value.Trim() == "" )
RaiseFirstNameStatusChanged(Status.Bad);
else
{
model_.FirstName = value;
RaiseFirstNameStatusChanged(Status.Normal);
}
}
}
private void RaiseFirstNameStatusChanged(Status newStatus)
{
if ( FirstNameStatusChangedEvent != null )
FirstNameStatusChangedEvent(newStatus);
}
}
And the view would provide handlers for the FirstNameStatusChanged event:
class View : Form
{
private Controller controller_;
private static readonly Dictionary<Controller.Status, Color> statusColors_ = new Dictionary<Controller.Status, Color>
{
{Controller.Status.Normal, SystemColors.Window},
{Controller.Status.Required, ControlRequired},
{Controller.Status.Good, ControlGood},
{Controller.Status.Bad, ControlRed}
};
public View(Controller controller)
{
InitializeComponent();
controller_ = controller;
contoller_.FirstNameStatusChangedEvent += OnFirstNameStatusChanged;
}
private void txtFirstname_TextChanged(object sender, EventArgs e)
{ controller_.FirstName = txtFirstName.Text; }
private void OnFirstNameStatusChanged(Controller.Status newStatus)
{ txtFirstName.BackColor = statusColors_[newStatus]; }
}
Most of what you doing in your code belongs to the Controller class since it describes the the logic. Your View should just describe UI and give easy access to UI components. Model class should describe your data model.
The idea is simple: Controller does everything, but it has to know about the View and the Model. For example as View is initialized, Controller sets up all the logic ( kinda what you already doing). As Model is assigned to the Controller - it sets the values into appropriate UI controls and does the same to retrieve data and return is as Model.
So basically you give your data model class to the controller, it does the editing and returns your data as model class again.
It would be very hard to follow MVC in classic ASP.NET if possible, so I will reply based on MVP.
On your first example, you are trying to do a validation. Validating a surname is the responsibility of Presenter. Showing the field red is the responsibility of View. So, your view class would be like this:
private void Page_Load()
{
this._presenter = new Presenter();
}
private void txtLastname_TextChanged(object sender, EventArgs e)
{
txtLastName.BackColor = presenter.IsLastnameValid(txtLastName.Text) ?
ControlGood : ControlBad;
}
And your presenter class would be something like this:
public Presenter()
{
public bool IsLastNameValid(string lastname)
{
return string.IsNullOrEmpty(lastname);
}
}
Last name is your model here.
Please note that I prepared this classes only for showing how would you form an MVP structure. In real world, there are lots of better ways to do validation. Normally you would use this approach for your business instead of validation.
Ian,
If you want the controls to validate immediately, you need to use javascript or jQuery. This is also true for classic ASP.NET. Since you are using Code Behind methods, I assume that your validation waits for a postback.
The following examples are from the NerdDinner project. NerdDinner is an open source project that serves as an example of ASP.NET MVC architecture. The authors have graciously provided a tutorial with it, available at http://nerddinnerbook.s3.amazonaws.com/Intro.htm
When a form is submitted in ASP.NET MVC, it enters the corresponding controller as a FormCollection object:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Edit(int id, FormCollection formValues) {
Dinner dinner = dinnerRepository.GetDinner(id);
try
{
UpdateModel(dinner);
dinnerRepository.Save();
}
catch
{
ModelState.AddModelErrors(dinner.GetRuleViolations())
}
return RedirectToAction("Details", new { id = dinner.DinnerID });
}
UpdateModel takes the form values and attempts to stuff them into the dinner object. The dinner object looks like this:
public partial class Dinner {
public bool IsValid {
get { return (GetRuleViolations().Count() == 0); }
}
public IEnumerable<RuleViolation> GetRuleViolations() {
yield break;
}
public IEnumerable<RuleViolation> GetRuleViolations() {
if (String.IsNullOrEmpty(Title))
yield return new RuleViolation("Title is required", "Title");
if (String.IsNullOrEmpty(Description))
yield return new RuleViolation("Description is required", "Description");
if (String.IsNullOrEmpty(HostedBy))
yield return new RuleViolation("HostedBy is required", "HostedBy");
if (String.IsNullOrEmpty(Address))
yield return new RuleViolation("Address is required", "Address");
if (String.IsNullOrEmpty(Country))
yield return new RuleViolation("Country is required", "Address");
if (String.IsNullOrEmpty(ContactPhone))
yield return new RuleViolation("Phone# is required", "ContactPhone");
if (!PhoneValidator.IsValidNumber(ContactPhone, Country))
yield return new RuleViolation("Phone# does not match country", "ContactPhone");
yield break;
}
partial void OnValidate(ChangeAction action) {
if (!IsValid)
throw new ApplicationException("Rule violations prevent saving");
}
}
Notice the IsValid method and the RuleViolations enumerator. If everything is set up properly, all you have to do is define your validations in here, and ASP.NET MVC will take care of the rest for you.
The final validated result looks like this:
I encourage you to get the NerdDinner application and tutorial at http://nerddinner.codeplex.com/