What is the benefit of creating a ModelBinder when using lib.web.mvc. ?
This example from 2011 does not use a ModelBinder
http://tpeczek.com/2011/03/jqgrid-and-aspnet-mvc-strongly-typed.html
public class ProductViewModel
{
#region Properties
public int Id { get; set; }
public string Name { get; set; }
[JqGridColumnSortingName("SupplierId")]
public string Supplier { get; set; }
[JqGridColumnSortingName("CategoryId")]
public string Category { get; set; }
[DisplayName("Quantity Per Unit")]
[JqGridColumnAlign(JqGridColumnAligns.Center)]
public string QuantityPerUnit { get; set; }
[DisplayName("Unit Price")]
[JqGridColumnAlign(JqGridColumnAligns.Center)]
public decimal? UnitPrice { get; set; }
[DisplayName("Units In Stock")]
[JqGridColumnAlign(JqGridColumnAligns.Center)]
public short? UnitsInStock { get; set; }
#endregion
#region Constructor
public ProductViewModel()
{ }
public ProductViewModel(Product product)
{
this.Id = product.Id;
this.Name = product.Name;
this.Supplier = product.Supplier.Name;
this.Category = product.Category.Name;
this.QuantityPerUnit = product.QuantityPerUnit;
this.UnitPrice = product.UnitPrice;
this.UnitsInStock = product.UnitsInStock;
}
#endregion
}
But the latest examples are using them
http://tpeczek.codeplex.com/SourceControl/latest#trunk/ASP.NET%20MVC%20Examples/jqGrid%20Examples/jqGrid/Models/ProductViewModel.cs
namespace jqGrid.Models
{
[ModelBinder(typeof(ProductViewModelBinder))]
public class ProductViewModel
{
#region Properties
public int? ProductID { get; set; }
public string ProductName { get; set; }
public int SupplierID { get; set; }
public int CategoryID { get; set; }
public string QuantityPerUnit { get; set; }
public decimal UnitPrice { get; set; }
public short UnitsInStock { get; set; }
#endregion
}
public class ProductViewModelBinder : DefaultModelBinder
{
public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
ProductViewModel model = (ProductViewModel)base.BindModel(controllerContext, bindingContext);
if (controllerContext.HttpContext.Request.Params["id"] != "_empty")
model.ProductID = Convert.ToInt32(controllerContext.HttpContext.Request.Params["id"]);
model.SupplierID = Convert.ToInt32(controllerContext.HttpContext.Request.Params["Supplier"]);
model.CategoryID = Convert.ToInt32(controllerContext.HttpContext.Request.Params["Category"]);
model.UnitPrice = Convert.ToDecimal(controllerContext.HttpContext.Request.Params["UnitPrice"].Replace(".", CultureInfo.CurrentCulture.NumberFormat.NumberDecimalSeparator));
return model;
}
}
Model Binders provide one of the most convenient functions that MVC has to offer. Model Binders' main job is to convert HTML Query Strings to strong-types. Out of the box, MVC model binders do an excellent job, but you may have a strong-type that doesn't work with the default binders. In that case you can create your own. Or you can customize them for example, maybe the postback only contains a single string value that you want to return an entire class or even a viewmodel packed with stuff.
Couple of things to keep in mind with the default behavior are: 1) MVC news up instances on it's own of Action Methods that take a first parameter of a model or view model class! 2) It will then attempt to populate that new instance with data returned from the Web Form (using Name/Value pairs) of the Query string. 3) Validation of the object (fields) happens before the first line in the controller is executed. 4) MVC model binding will NOT throw an error if there is missing field data (make sure your posted form fields have everything you need.
Finally with the functionality described above you can go a long way without writing custom binders. However they are there to handle the edge cases or any "tricks" you want to implement to make your application lean and mean. For me, I almost always use strongly-typed views and view-models as MVC does a great job of supporting full view binding to view models.
Related
I use Asp.Net MVC, Entity Framework. I have a form it looks like below.
Here, dropdownlist is filled from a table(types). Checkboxes is filled from another table(test). Tables are like below:
public class Types
{
public int TypesID{get;set;}
public string TestName { get; set; }
public string TestExplanation { get; set; }
public int TestTime { get; set; }
}
public class Tests
{
public int TestID{get;set;
public string Name { get; set; }
public string Code { get; set; }
}
public class Types_Tests
{
public int Types_TestsID{ get; set; }
public int TypesID { get; set; }
public int TestsID { get; set; }
public virtual Types Types { get; set; }
public virtual Tests Tests { get; set; }
}
Types_test table is relation table between Types and Tests. When I click Kaydet button, it shuld save type and checked tests. I made this operation using ViewBag, javascript and hdnvalue.I added checked checkboz values to a hdntext. I made saving process like below:
[HttpPost]
public ActionResult Index(string drpType, string hdntesttypes)
{
var TypeList = Types.GetAll();
ViewBag.TypesList = new SelectList(TypeList, "Id", "Name");
var testypeList = testTypes.GetAll();
ViewBag.TestTypesList = new SelectList(testypeList, "Id", "TestName");
GenericRepository<TestDisabledTypes> testDisabledRepository = new GenericRepository<TestDisabledTypes>(_context);
if (!string.IsNullOrEmpty(hdntesttypes))
{
string[] disabletypesArray = hdntesttypes.Split(',');
using (TransactionScope trns = new TransactionScope())
{
for (int i = 0; i < disabletypesArray.Length; i++)
{
Test_Types types = new Test_Types ();
types.TestTypesID = Convert.ToInt32(disabletypesArray[i]);
types.TypesID = Convert.ToInt32(drpType);
testDisabledRepository.Insert(types);
}
trns.Complete();
}
}
return View();
}
It wokrs. But I search better solution for this process. Can someone give me any idea?
Thanks.
If you don't need additional attributes for your entity class, you don't need create link table.
Just define the following class, and EF will generate the link table for you automatically.
public class Type
{
public int TypesID{get;set;}
public string TestName { get; set; }
public string TestExplanation { get; set; }
public int TestTime { get; set; }
public ICollection<Test> Tests { get; set; }
}
public class Test
{
public int TestID{get;set;
public string Name { get; set; }
public string Code { get; set; }
public ICollection<Type> Types {get;set;}
}
Well, in EntityFramework if you want to create a many to many relation object you need to create new object of "linking" entity. Unfortunately, it is not possible to add first object, add second object and say "Guys, you are in many to many relationships. Are you happy then?" :) You need to create relation object, set appropriate fields in it (I think these are ids of two objects itself) and add it to relation collection (entity) in your model. But before doing so you need to be sure that objects with data you are linking with are already exists in database. Otherwise you'll get an error
Also it's not necessary to create manually transaction because EF does it for you automatically each time you get/save your data
Hope someone can help - this has been bugging me for around 2 hours - its probably something simple :)
Kendo UI Grid sends a request to my controller
http://localhost:1418/user/update?UserID=1&UserName=Admin&RoleName=Admin&Email=c.j.hannon%40gmail.com&Active=true&Company%5BCompanyID%5D=1&Company%5BCompanyName%5D=asd
However, the controller class 'Company' isnt bound by the binder? Can any one help my view model and controller action signature are below:
[HttpGet]
public JsonResult Update(UserViewModel model)
{
svcUser.UpdateUser(new UpdateUserRequest() {
UserID=model.UserID,
RoleID = model.RoleName,
Email = model.Email,
Active = model.Active.GetValueOrDefault(false),
UserName = model.UserName
});
return Json("", JsonRequestBehavior.AllowGet);
}
public class UserViewModel
{
public int UserID { get; set; }
public string UserName { get; set; }
public string RoleName { get; set; }
public string Email { get; set; }
public bool? Active { get; set; }
public CompanyViewModel Company { get; set; }
}
Cheers
Craig
A few things. Your immediate problem is that Company is mapped to a complex object not a primitive type. Kendo Grid just does not do this (as of this writing). Just guessing, but you probably want to setup a foreign key binding on the Grid and just pass back the Id of the company from a listbox. This is not as bad as you think and it will immediatly fix your problem and look nice too.
Maybe personal taste but seems to be a convention. Use the suffix ViewModel for the model that is bound to your View and just the suffix Model for your business objects. So a Kendo Grid is always populated with a Model.
Ex.:
public class UserModel
{
public int UserID { get; set; }
public string UserName { get; set; }
public string RoleName { get; set; }
public string Email { get; set; }
public bool? Active { get; set; }
public int CompanyID { get; set; }
}
public class CompanyModel
{
public int ID { get; set; }
public string Name { get; set; }
}
public class UserViewModel
{
public UserModel UserModel { get; set; }
public IList<CompanyModel> Companies { get; set; }
}
public ActionResult UserEdit(string id)
{
var model = new UserViewModel();
model.UserModel = load...
model.Companies = load list...
return View(model);
}
#model UserViewModel
...
column.ForeignKey(fk => fk.CompanyId, Model.Companies, "ID", "Name")
(Razor Notation)
BUT! This is just an example, you are better off Ajax loading the Grid with the IList becuase I assume you have many Users in the Grid at once, though you could server bind off the ViewModel with a List too. But the list of Companies is probably the same every time, so map it to the View just liek this rather than Ajax load it every time you do a row edit. (not always true)
I'm trying to do something i that feels like a small task, but i cannot figure out a simple way to do it. All my approaches for doing this gets really complex for a simple task.
I have these models:
public class Blog
{
public int Id { get; set; }
public String Name { get; set; }
public virtual ICollection<Post> Posts { get; set; }
}
public class Post
{
public int Id { get; set; }
public String Name { get; set; }
public int BlogId { get; set; }
public virtual ICollection<Comment> Comments { get; set; }
}
public class Comment
{
public int Id { get; set; }
public String CommentText { get; set; }
public int PostId { get; set; }
public int UserProfileUserId { get; set; }
}
public class UserProfile
{
public int UserId { get; set; }
public string UserName { get; set; }
public String FirstName { get; set; }
public String LastName { get; set; }
}
In the Added Comments partial view, i want to show the full user name of the user that made a comment. If i just use my base classes in my views and partial views, i get everything i need except full user name on added comments. So far, i've thought of the following ways:
ViewModels - This will result in creating a ViewModel for each of my Classes and then populate / map them manually in my controller.
Code in Views - I have the UserProfileUserId so i can just ask the repository from the view but this Kills the MVC in MVC so i don't want to do it.
Actually Adding UserProfileFirstName and UserProfileLastName to the Comment Class as foreign keys - This feels like filling the database with view specific data. It doesn't belong in a relational database.
Using regular SQL and Query the database - Just because i know SQL, this -could- be a way to do it. but then again i'm killing the MVC in MVC.
How should i do this? Where is my silly overlooked option? I've searched a lot but could not find an answer, but this could be related to me not knowing all the technical terms yet. Sorry if this is answered 1000 times before.
Ideally i would change my domain model to include a Author property of type UserProfile and load that data as well using a JOIN (Comment table and User table)
public class Comment
{
public int Id { get; set; }
public String CommentText { get; set; }
public int PostId { get; set; }
public UserProfile Author { get; set; }
}
EDIT : As per the questions in the comment
This is how i will do this.
My Repositary method will have these methods
List<Comment> GetCommentsForPost(int postId);
BlogPost GetPost(int postId);
I would have ViewModel for representing a single blog post like this
public class PostViewModel
{
public int PostID { set;get;}
public string PostText { set;get;}
public string AuthorDisplayName { set;get;}
public List<CommentViewModel> Comments { set;get;}
public PostViewModel()
{
Comments=new List<CommentViewModel>();
}
}
public class CommentViewModel
{
public int CommentID {set;get;}
public string Text { set;get;}
public string AuthorDisplayName { set;get;}
}
Now in your GET Action, Get the data from your Repositary and Map that to ViewModel and send it to view
public ActionResult ViewPost(int id)
{
var post=repositary.GetPost(id);
if(post!=null)
{
PostViewModel vm=new PostViewModel { PostID=id };
vm.PostText=post.Name;
var comments=repo.GetCommentsForPost(id);
foreach(var item in comments)
{
vm.Comments.Add(new CommentViewModel { CommentID=item.Id,
AuthorDisplayName=item.Author.FirstName});
}
return View(vm);
}
return View("NotFound");
}
Now your view will be strongly typed to The PostViewModel
#model PostViewModel
<h2>#Model.PostText</h2>
#Html.Partial("Comments",Model.Comments)
And your partial view(Comments.cshtml) will be strongly typed to a collection of CommentViewModel
#model List<CommentViewModel>
#foreach(var item in Model)
{
<div>
#item.Text
<p>Written by #item.AuthorDisplayName</p>
</div>
}
Now our views are not depending directly to Domain models. This allows us to bring data from another source tomorrow if we need (Ex :Get comments from a web service) and simply map to our view model.
Some notes
Do not add too much of code to Views. Let's keep it pure HTML as much as possible. No data access calls directly from Views!
I manually mapped the domain model to viewmodel for your understanding. You may use a mapping library like Automapper to do so. Also you may move part of the code we have in the GET action method to another servier layer so that it can be reused in multiple places.
I'm very new to ASP.NET MVC, so forgive me if this is something I should know. I haven't seen any obvious documentation on it, so here goes:
I have a LINQ to Entities data model and a MVC project. I use a lot of javascript/jquery, so have opted to access my data from the client through a WebAPI as json objects. However, I don't want to pass all the entity object properties though to the client, so I have added separate models to my MVC project in which I handle MVC model validation and Binding to my Views. Also, in order to work with it in my jquery, I have created json versions of the models.
This is only the start of the project and I don't want to start it off on the wrong foot. Having three versions of my models for each entity in my business layer is going to be a nightmare! I am sure that the overall structure of my project is a very common one, but can't see many developers settling for such duplication of code. There must be a better way of implementing it.
Any thoughts? Really appreciate any input.
In answer to your comment above - you can create your javascript viewmodel as a standard js object. I tend to use Knockout.js so it would look like this:
jsController.Resource = function (data) {
self.UserId = ko.observable(data.UserId);
self.FullName = ko.observable(data.Name);
self.RoleName = ko.observable(data.RoleName);
self.RoleId = ko.observable(data.RoleId);
}
and then use an ajax post method to post it to your MVC action
jsController.addToUndertaking = function (resource, isAsync) {
mylog.log("UndertakingId at post = " + jsController.undertakingId);
var action = $.ajax({
type: "POST",
url: "/TeamMember/AddUserToUndertaking",
data: resource,
cache: false,
async: isAsync
});
action.done(function () {
resource.AllocatedToUndertaking(true);
//Do other funky stuff
});
};
Create your MVC action so that it accepts a forms collection as so:
public ActionResult AddUserToUndertaking(FormCollection postedResource)
{
if (Request.IsAjaxRequest() == false)
{
const string msg = "Non ajax request received";
Logger.ErrorFormat(msg);
throw new SecurityException(msg);
}
if (postedResource == null)
{
Logger.Debug("Null resource posted - terminating.");
return new HttpStatusCodeResult(500);
}
var resource = new AllocatedResourceAjaxViewModel(postedResource);
//Do something Funky
return new HttpStatusCodeResult(200);
}
and then you create your MVC viewmodel from the forms collection (i tend to do this by passing in the forms collection as a constructor method to the viewmodel).
public class AllocatedResourceAjaxViewModel
{
public int UserId { get; set; }
public string Name { get; set; }
public string RoleName { get; set; }
public int RoleId { get; set; }
public AllocatedResourceAjaxViewModel()
{}
public AllocatedResourceAjaxViewModel(NameValueCollection formData)
{
UserId = JsFormDataConverter.Int(formData["UserId"]);
Name = Convert.ToString(formData["FullName"]);
RoleName = Convert.ToString(formData["RoleName"]);
RoleId = JsFormDataConverter.Int(formData["RoleId"]);
}
}
As a null int in your javascript VM will lead to a string of 'undefined' being passed you need a converter method to safely extract non strings.
public static class JsFormDataConverter
{
public static bool Boolean(string formValue, bool defaultValue = false)
{
if (formValue.ToLower() == "true") return true;
if (formValue.ToLower() == "false") return false;
return defaultValue;
}
public static int Int(string formValue, int defaultValue = 0)
{
int result;
return int.TryParse(formValue, out result)
? result
: defaultValue;
}
}
and there you go. I am sure you can improve on the above but that will get you going.
The way that I have always worked is that you have your Models e.g. Order & OrderLines which are where you store all your data and get hydrated either directly from the database by SQL or (more usually these days ) by an ORM such as NHibernate or Entity Framework.
You then have ViewModels - these are used to transport the data from your application to the views - either directly ie a strongly typed view bound to say an OrderViewModel or via an action returning a JsonResult.
A OrderViewModel is not a duplication of Order as it is designed to only hold the data that is needed to be presented on the screen (If you have many different views displaying an Order in different ways it could be perfectly acceptable to have many different ViewModels -one for each view containing only the fields needed for each view). ViewModels should also not contain any complex types except other ViewModels. this helps keep accidental data access out of the views (think security and performance).
So Given
public class Order
{
public int Id { get; set; }
public DateTime OrderDate { get; set; }
public User User { get; set; }
public string Description { get; set; }
public List<OrderLine> OrderLines { get; set; }
}
public class OrderLine
{
public int Id { get; set; }
public Order Order { get; set; }
public String Description { get; set; }
public int Quantity { get; set; }
public int Weight { get; set; }
public int Price { get; set; }
}
public class User
{
public int Id { get; set; }
public string Name { get; set; }
}
You could have the two ViewModels
public class OrderViewModel
{
public int ID { get; set; }
public List<OrderLineViewModel> OrderLines { get; set; }
public DateTime OrderDate { get; set; }
public int UserId { get; set; }
public string Description { get; set; }
}
public class OrderLineViewModel
{
public int Id { get; set; }
public int OrderId { get; set; }
public String Description { get; set; }
public int Quantity { get; set; }
public int Weight { get; set; }
public int Price { get; set; }
}
The view models could then be serialized into JSON as needed or marked up with validation attributes etc.
I have a class, which has 8 properties / 8 columns in DB. In the Edit page, I want to exclude the AddedDate and UserID fields. When a user edits a voucher, he can't overwrite the AddedDate or UserID values in the DB.
public class Voucher
{
public int ID { get; set; }
public string Title { get; set; }
public string SiteName { get; set; }
public string DealURL { get; set; }
public DateTime AddedDate { get; set; }
public DateTime? ExpirationDate { get; set; }
public string VoucherFileURL { get; set; }
public Guid UserID { get; set; }
}
Here is what I have for Edit controller:
// POST: /Voucher/Edit/5
[HttpPost]
public ActionResult Edit([Bind(Exclude = "AddedDate")]Voucher voucher)
{
if (ModelState.IsValid)
{
db.Entry(voucher).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(voucher);
}
On Edit page, when I click on submit, I got the following error:
System.Data.SqlServerCe.SqlCeException: An overflow occurred while converting to datetime.
Seems like the AddedDate didn't get excluded from the voucher object and triggered the error.
Would you please let me know how to fix it? Thanks!
(it is an updated version of asp.net mvc3 UpdateModel exclude properties is not working, I will go with another approach)
Never use your domain entities as action arguments and never pass your domain entities to your views. I would recommend you to use view models. In the view model you will include only the properties that you want to be bound from the view. The view model is a class that's specifically tailored to the requirements of a given view.
public class VoucherViewModel
{
public int ID { get; set; }
public string Title { get; set; }
public string SiteName { get; set; }
public string DealURL { get; set; }
public DateTime? ExpirationDate { get; set; }
public string VoucherFileURL { get; set; }
}
and then:
[HttpPost]
public ActionResult Edit(VoucherViewModel model)
{
// TODO: if the view model is valid map it to a model
// and pass the model to your DAL
// To ease the mapping between your models and view models
// you could use a tool such as AutoMapper: http://automapper.org/
...
}
UPDATE:
In the comments section #Rick.Anderson-at-Microsoft.com points out that while I have answered your question I haven't explained where the problem comes from.
The thing is that DateTime is a value type meaning it will always have a value. The [Bind(Exclude = "AddedDate")] works perfectly fine and it does what it is supposed to do => it doesn't bind the AddedDate property from the request. As a consequence the property will have its default value which for a DateTime field is 1/1/0001 12:00:00 AM and when he attempts to save this in SQL Server it blows because SQL Server doesn't support such format.