I'm trying to write my first very own SiteMapProvider subclass. It is meant to be populated dynamically using a bunch of different database lookups, much like all of the examples I've found on the web.
However, there are a whole bunch of things that are quite unclear to me. Here are my two first questions:
Why is StaticSiteMapProvider used in virtually everyone's project instead of SiteMapProvider? Since the class contains the name "static", I'm getting the impression that it's not as...well, dynamic as I want it.
Can someone provide me with a super-minimalistic SiteMapProvider subclass which populates the map using only static data, i.e. no database access, etc.?
SiteMapProvider can be tottaly dynamic. For example it can make dynamic lookup just for nodes. In contrast with StaticSiteMapProvider you should know whole structure. So this for you to decide what to choose.
You can look at the XmlSiteMapProvider, this is good example of "static" map provider.
public class CoolMapProvider : StaticSiteMapProvider
{
public override SiteMapNode BuildSiteMap()
{
var root = new SiteMapNode(this, "test", "~/test.aspx");
base.AddNode(root, null);
base.AddNode(new SiteMapNode(this, "test-child", "~/test_child.aspx"), root);
return root;
}
}
I did not checked this, but should work.
Related
Current project:
ASP.NET 4.5.2
MVC 5
EF 6
In all honesty, I have never made use of a mapper before, and while the ExpressMapper tutorial bounces across the high-altitude highlights, it makes several assumptions about knowledge that I don’t have.
So in no general order:
The product is supposed to have all its code centralized in one spot. Where is this spot? Where do I put it? The examples start out with,
public void MappingRegistration() {
Mapper.Register<Product,ProductViewModel>();
}
But I don’t know where to put this. Does it go into its own file or is it in another file, such as within App_Start?
If it is elsewhere in the project, do I create it under its own namespace?
If I have a viewModel that is filled in a different way than its dataModel is filled, how do I handle each type separately? As in, the data is pulled out of the DB and fills the viewModel with completely different conditional rules than how the data is pulled from the viewModel and inserted into or updated back to the database.
How do I bring in external conditionals that affect how the data and which data is inserted into the DB, such as the Role of the user, their UserId and UserName, and various project Settings? Depending on conditionals, some entries may end up with a null value instead of an actual value. How can I do business logic validation using these conditionals (User is actually updating his own record, by comparing their session UserId with the UserId stored in the DB)?
Right now I am doing a lot of manual mapping in the Models but this is problematic especially since the method I am using (to cut down on code in the controller) means that during an update I cannot examine an entry in the DB prior to updating it in the DB.
You can stick it anywhere you want - the only thing necessary is that it gets called in code, before you call Mapper.Map<Product,ProductViewModel>.
E.g.
public static void main()
{
Mapper.Register<Product,ProductViewModel>();
}
is functionally the same as
public static void main()
{
RegisterMapping();
}
public static void RegisterMapping()
{
Mapper.Register<Product,ProductViewModel>();
}
If you want to map one class member to another class member with a different name, you can specify it with Member mapping.
Mapper.Register<Product, ProductViewModel>()
.Member(dest => dest.efgh, src => src.abcd);
If you want to apply special conversion rules, you can specify that with a Function mapping - e.g. you want the price in the ProductViewModel to be 2x the price of the product :
Mapper.Register<Product, ProductViewModel>()
.Function(dest => dest.Price, src => src.Price*2);
Any customisation that you make to the mapping should be done at the time you register the mapping, and has to be done on a Member-by-Member basis AFAIK.
If there's anything else specific that you need help with, leave a comment.
I've been at this same question in different forms now for a while (see e.g. Entity Framework and MVC 3: The relationship could not be changed because one or more of the foreign-key properties is non-nullable ), and it's still bugging me, so I thought I'd put it a little more generically:
I feel this can't be a very unusual problem:
You have an entity object (using Entity Framework), say User. The User has some simple properties such as FirstName, LastName, etc. But it also has some object property lists, take the proverbial example Emails, to make this simple. Email is often designed as a list of objects so that you can add to that object properties like Address and Type (Home, Work, etc). I'm using this as an example to keep it generic, but it could be anything, the point is, you want the user to be able to add an arbitrary number of these items. You should also be able to delete items (old address, or whatever).
Now, in a normal web page you would expect to be able to add these items in the same View. But MVC as it seems designed only makes it easy to do this if you call up an entirely new View just to add the address. (In the template for an Index View you get the "Create New" link e.g.).
I've come across a couple of examples that do something close to what I mean here:
http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx
and
http://blog.stevensanderson.com/2010/01/28/editing-a-variable-length-list-aspnet-mvc-2-style/
The problem is, although the sample projects on these sites work fine, with mock model objects, and simply lists (not an object with a child list), it's a different thing if you actually want to do something with the posted information - in my case save to database through the Entity Framework model. To adapt these cases to that, all of a sudden I'm in a maze of intricate and definitely not DRY code... Juggling objects with AutoMapper and whatnot, and the Entity Framework won't let you save and so on (see above link if you're interested in the details).
What I want to get at is, is it really possible that this is such an uncommon thing to want to do? Update a child collection in the same View as the parent object (such as the email addresses in this case)? It seems to me it can't be uncommon at all, and there must be a standard way of handling this sort of scenario, and I'm just missing it (and no one here so far has been able to point me to a straighforward solution, perhaps because I made it too abstract with my own application examples).
So if there is a simple solution to what should in my view be a simple problem (since the design is so common), please tell me.
Have you tried updating the project at your link to Steven Anderson's blog to bind to a complex object? Create a class in models called Sack and give it a single property and see if you can get it to work.
public class Sack
{
public IEnumberable<Gift> Gifts { get; set; }
}
It only took me a minute to get it up and running as I think you intend. The improvement I would have made next would be to add an HtmlHelper extension that is essentially the same as Html.EditorFor(m => m.SomeProperty), only call it something more meaningful and have it interface with the prefix scope extensions provided in the project.
public static class HtmlExtensions
{
public static IHtmlString CollectionEditorFor<TModel, TValue>(this HtmlHelper html, Expression<Func<TModel, TValue>> expression)
{
if (/* type of expression value is not a collection */) throw new FailureToFollowTheRulesException("id10t");
// your implementation
}
}
I'm working on a site and there are two projects in the solution a business logic project and the website project. I understand that I want to keep the entity context out of the web project and only use the business objects the framework creates but I can't figure out how to save a modified object this way.
Let's say my entity model created this class:
public class Person //Person entity
{
Int32 Id {get;set;}
String Name {get;set;}
Address Address {get;set;} //Address entity
}
And I created this class to get a specific person:
public static class PersonController
{
public static Person GetById(int id)
{
using (Entities context = new Entities())
{
return context.Persons.FirstOrDefault(x => x.Id == id);
}
}
}
This allows me to get a person without a context by calling PersonController.GetById(1); and I can change the persons properties after I get them but I can't figure out how to save the modified information back to the database. Ideally I would like to partial class Person and add a .Save() method which would handle creating a context adding the person to it and saving the changes. But when I tried this a while ago there were all kinds of issues with it still being attached to the old context and even if I detatch it and attatch it to a new context it gets attached as EntityState.Unchanged, if I remember right, so when I call context.SaveChages() after attaching it nothing actually gets updated.
I guess I have two questions:
1) Am I going about this in a good way/is there a better way? If I'm doing this in a really terrible way I would appreciate some psudo-code to point me in the right direction; a link to a post explaining how to go about this type of thing would work just as well.
2) Can someone provide some psudo-code for a save method? The save method would also need to handle if an address was attached or removed.
There are many ways to handle Entity Framework as a persistence layer.
For one, it looks like you're not using pure POCOs. That is, you let EF generate the classes for your (in the EDMX.designer.cs file).
Nothing wrong with that, but it does inhibit a clean separation of concerns (especially when it comes to unit testing).
Have you considering implementing the Repository pattern to encapsulate your EF logic? This would be a good way to isolate the logic from your UI.
In terms of Save - this is where it gets difficult. You're right, most people use partial classes. Generally, you would have a base class which exposes a virtual "Save" method, which the partial classes can then override.
I personally don't like this pattern - i believe POCOs should not care about persistence, or the underlying infrastructure. Therefore I like to use pure POCOs (no code gen), Repository pattern and Unit of Work.
The Unit of Work handles the context opening/saving/closing for you.
This is how (my) Unit of Work does the magic. Consider this some code in your "Web" project:
var uOw = new UnitOfWork(); // this is class i created, implementing the UOW pattern
var person = repository.Find(10); // find's a "Person" entity (pure POCO), with id 10.
person.Name = "Scott";
uOw.Commit();
Or adding a new Person:
var uOw = new UnitOfWork();
var newPerson = new Person { Name = "Bob" };
repository.Add(newPerson);
uOw.Commit();
How nice is that? :)
Line 1 creates a new sql context for you.
Line 2 uses that same context to retrieve a single "Person" object, which is a hand-coded POCO (not generated by EF).
Line 3 changes the name of the Person (pure POCO setter).
Line 4 Saves the changes to the data context, and closes the context.
Now, there is a LOT more to these patterns than that, so I suggest you read up on these patterns to see if it suits you.
My repository is also implemented with Generics, so I can re-use this interface for all business entity persistence.
Also take a look at some of the other questions I have asked on Stack Overflow - and you can see how I've implemented these patterns.
Not sure if this is the "answer" you're looking for, but thought I'd give you some alternative options.
Grails offers the ability to automatically create and bind domain objects to a hasMany List, as described in the grails user guide.
So, for example, if my domain object "Author" has a List of many "Book" objects, I could create and bind these using the following markup (from the user guide):
<g:textField name="books[0].title" value="the Stand" />
<g:textField name="books[1].title" value="the Shining" />
<g:textField name="books[2].title" value="Red Madder" />
In this case, if any of the books specified don't already exist, Grails will create them and set their titles appropriately. If there are already books in the specified indices, their titles will be updated and they will be saved. My question is: is there some easy way to tell Grails to remove one of those books from the 'books' association on data bind?
The most obvious way to do this would be to omit the form element that corresponds to the domain instance you want to delete; unfortunately, this does not work, as per the user guide:
Then Grails will automatically create
a new instance for you at the defined
position. If you "skipped" a few
elements in the middle ... Then Grails
will automatically create instances in
between.
I realize that a specific solution could be engineered as part of a command object, or as part of a particular controller- however, the need for this functionality appears repeatedly throughout my application, across multiple domain objects and for associations of many different types of objects. A general solution, therefore, would be ideal. Does anyone know if there is something like this included in Grails?
removeFrom*
Opposite of the addTo method in that it removes instances from an association.
Examples
def author = Author.findByName("Stephen King")
def book = author.books.find { it.title = 'The Stand' }
author.removeFromBooks(book)
Just ran into this issue myself. It's easy to solve. Grails uses java.util.Set to represent lists. You can just use the clear() method to wipe the data, and then add in the ones you want.
//clear all documents
bidRequest.documents.clear()
//add the selected ones back
params.documentId.each() {
def Document document = Document.get(it)
bidRequest.documents.add(document)
log.debug("in associateDocuments: added " + document)
};
//try to save the changes
if (!bidRequest.save(flush: true)) {
return error()
} else {
flash.message = "Successfully associated documents"
}
I bet you can do the same thing by using the "remove()" method in the case that you don't want to "clear()" all the data.
For a good explanation of deleting a collection of child objects with GORM have a look at the Deleting Children section of this blog post - GORM gotchas part 2
It's recommended reading, as are parts 1 and 3 of the series.
I am just starting to learn Grails myself and saw your question as an interesting research exercise for me. I do not think you can use the conventional data binding mechanism - as it fills in the blanks using some kind of Lazy map behind the scenes. So for you to achieve your goal your "save" method (or is it a function?) is unlikely to contain anything like:
def Book = new Book(params)
You need a mechanism to modify your controller's "save" method.
After some research, I understand you can modify your scaffolding template which is responsible for generating your controller code or runtime methods. You can get a copy of all the templates used by Grails by running "grails install-templates" and the template file you would need to modify is called "Controller.groovy".
So in theory, you could modify the "save" method for your whole application this way.
Great! You would think that all you need to do now is modify your save method in the template so that it iterates through the object entries (e.g. books) in the params map, saving and deleting as you go.
However, I think your required solution could still be quite problematic to achieve. My instinct tells me that there are many reasons why the mechanism you suggest is a bad idea.
For one reason, off the top of my head, imagine you had a paginated list of books. Could that mean your "save" could delete the entire database table except the currently visible page? Okay, let us say you manage to work out how many items are displayed on each page, what if the list was sorted so it was no longer in numerical order - what do you delete now?
Maybe multiple submit buttons in your form would be a better approach (e.g. save changes, add, delete). I have not tried this kind of thing in Grails but understand actionSubmit should help you achieve multiple submit buttons. I certainly used to do this kind of thing in Struts!
HTH
I'm just running into this same issue.
My application's domain is quite simple: it has Stub objects which have a hasMany relationship with Header objects. Since the Header objects have no life of their own, they're entirely managed by the Stub controller and views.
The domain class definitions:
class Stub {
List headers = new ArrayList();
static hasMany = [headers:Header]
static mapping = {headers lazy: false}
}
class Header {
String value
static belongsTo = Stub
}
I've tried the "clear and bind" method but the end result is that the "cleared" objects are left over in the database and grails will just create new instances for the ones that were not removed from the relationship. It does seem to work from an user's perspective, but it will leave lots of garbage objects in the database.
The code in the controller's update() method is:
stubInstance.headers.clear()
stubInstance.properties = params
An example: while editing the -many side of this relationship I have (for a given Stub with id=1):
<g:textField name="headers[0].value" value="zero" id=1 />
<g:textField name="headers[1].value" value="one" id=2 />
<g:textField name="headers[2].value" value="two" id=3 />
in the database there are 3 Header instances:
id=1;value="zero"
id=2;value="one"
id=3;value"two"
after removing header "one" and saving the Stub object the database will have headers:
id=1;value="zero"
id=2;value="one"
id=3;value"two"
id=4;value="zero"
id=5;value="two"
and the Stub object will now have an association with Headers with id=4 and id=5...
Furthermore, without the clearing of the list, if an index is not present in the submitted request.headers list, on data binding grails will keep the existing object at that location unchanged.
The solution that occurs to me is to bind the data, then check the Stub's headers for elements that are not present in the submitted list and remove them.
This looks like a pretty simple scenario, isn't there any built-in functionality to address it?
It's a bit overkill to have to write your own synchronization logic for maintaining relationships, especially when the quirks that make it non-trivial are caused by grails itself.
What about deletion, shouldn't the clear()'ed elements be gone from the database? Am I missing something in the relationship or domain object definitions?
class Stub {
List headers = new ArrayList();
static hasMany = [headers:Header]
static mapping = {
headers lazy: false
**headers cascade: "all-delete-orphan"**
}
}
class Header {
String value
static belongsTo = Stub
}
I have added the cascade property on the owning side of relationship and Now if you try to save the stub, it will take care of removing deleted items from the collection and delete them from the DataBase.
I'm generating dto classes with a template engine and would like to exclude some properties in an asmx webservice, what, if possible, is the best way to do this?
Ex:
[WebMethod]
public ProductPackages GetPackages()
{
ProductPackages packages = new ProductPackages();
packages.Packages.add(new PackageDTO());
return packages;
}
The PackageDTO contains some properties that's not relevant for this service.
But as the class can be regenerated any time i can't apply [XmlIgnore] to the fields.
So I'm looking for a way to apply a "exclude list" without touching the actual class.
Above is just an example, the template engine generates dto's for all tables in a given project, and I would like to be able to use them in services without needing to maintain a big bunch of nearly identical classes.
Just hit the same problem. You can exclude fields by marking them as internal.
public class Order
{
public double OrderPrice;
internal double ProfitMargin;
internal string TheTruthAboutThisCustomer;
}
If you don't want to return a field or property, then don't have it in the object you return! It's as simple as that.