In my app I have a criteria builder section that's built using jquery and is pitched back to the controller in a form post and picked up as IList by the model binder as suggested in Phil's post here: http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx
A really simple way that I'm persisting the criteria across posts is re-delivering the IList object to the view. I'm using a DisplayFor() template for this object, but because it's a list I need to know the index # inside of the template.
I'm hoping there's a context value somewhere.
Well, I couldn't find any information on that kind of meta data, so I had to crud up my view model to contain that index and another property. So now it's a simple Model.IndexItem on the template that returns it's order in the entire collection.
Related
I have an entity type "Post" and I would like to create a view that will show one random Post with a given category. I created a Data pipeline that grabs all posts and I created a view with ListPresentation = a "TemplateSettings" entity type that lets me choose categories.
I planned to use the Razor template to filter the items for those matching the categories in List.Presentation.Categories. But, I can't seem to reference List.Presentation.Categories. I get an error that System.Collections.Generic.List doesn't contain an entry for "Presentation". When I use #ListPresentation, the whole object in null... so #ListPresentation.Toolbar, etc. all throw errors, despite me having set a "Demo Item".
Can anybody see what would be wrong with this setup? How do I reference List Presentation stuff in Razor?
Thanks.
I figured this out... The direct thing seems to be "ListPresentation", but the snippets use "List.Presentation". Still, it wasn't working in my case because I was using a data query that didn't include the module data. So, I had to modify that query to include the module data as well as the full list of entities, regardless of the module. Then, I got the full list from one data stream, and the ListPresentation fields were available.
Note also that you can use ListContent.Presentation - that would be the newest, most consistent API which always places Presentation information as a property of the entity it's describing.
I'm trying to come up with a reusable pattern for updating MongoDB Documents when using Spring Data in conjunction with Spring MVC.
The use case can generally be summarized by:
A document is created in Mongo using repository.save()
Parts of that document are then presented in a Spring MVC editable form.
A user submits updated parts of that document which are then saved.
If I use the repository.save() method in step 3, I will lose any data in the document that was not bound to the form. Making the form responsible for the entire document is fragile so this is where it seems the findAndModify() method of the MongoTemplate comes in handy.
To use the findAndModify() method, I've created Form objects that support a toMap() method which takes the Form object's properties as a Map and removes some of the fields (e.g. class and id). This gets me a Map that contains only the fields that I care about from the Form object. Passing the object ID and this map to an update() method on my customized repository, I build Query and Update objects that I can pass to the findAndModify() method.
Using this approach, I'm able to add fields to my objects easily and only worry about instances when there are fields I don't want to update from a form posting. Document fields not manipulated by the Form should be retained. It still seems slightly convoluted to be using both the Repository and MongoTemplate so I'm wondering if there are better examples for how to handle this. It seems like this should be a consistent pattern when working with Mongo and Spring MVC (at the least).
I've created a sample project showing how I achieve this model on GitHub. The Spock Tests show how "updating" a Document using save() will blow away fields as expected and my update() method.
https://github.com/watchwithmike/diner-data
What are other people doing when dealing with partial updates to Documents using Spring MVC and Spring Data?
If you are taking whatever the user supplies and just shoving that in the database you are running the risk of doing something dangerous like updating or creating data that they shouldn't be able to. Instead, you should first query Mongo to get the most recent version of the document, change any fields (it looks like you are using Groovy so you could loop through all the properties and set them on the new document), and then save the new, complete document.
If you are making small, consistent updates (like increasing the number of votes, or something like that), you could create a custom MongoDB query using the MongoTemplate to do an update to a few fields. Check out the spring-data-mongodb docs for more. You can also add custom methods to the MongoRepository that use the MongoTemplate.
I have say class/ojbect one which I am returning as details. But then there is a second class that is related to the first that I want to list (and have an option to look at the details). How do I get return both of those?
Example is like in an item as the main piece but there may be details or other items that are related to the main item. I will select them with a linq query but then how do I return them to the same view?
Do I need to have some sort of partial or other form to display the second object type?
I don't see where returning the view I can return both.
My thought for right now is to create a new class that contains both of the object types but I know there has to be a better way.
My thought for right now is to create a new class that contains both of the object types but I know there has to be a better way.
That is the right way. Create a ViewModel class that contains all the data that view needs and pass it to view.
You can either pass it to View through ViewState or ViewBag (depending on which MVC version you are using).
for the first object "main object" return it as the model of this view and for the details
put them into ViewState and cast them back within the view
I am using in my views (asp mvc3/razor cshtml) references to the Request object (eg, #Request.Params["Name"]). Do you think this is a very bad practice? Should I rewrite the value in the controller Request.Params ["Name"] to ViewBag.Name and then use it in the view (#ViewBag.Name)?
Best practice is to use a model class. An instance of the model class is created or updated in your controller. Then the controller displays a strongly-typed view.
So I'd avoid direct access to the request from the view as well as the use of the view bag.
Should I rewrite the value in the controller Request.Params ["Name"] to ViewBag.Name and then use it in the view (#ViewBag.Name)?
Yes. You will avoid runtime errors if "Name" does not exist.
The IDE will not warn you of the NullReferenceException about to be thrown with the following code.
#Request.Params["Fake"].ToString()
Of course, you'll have to be careful about ViewBag.Fake being null as well.
I like to use the viewbag to store things not related to the model, for example if I have a dropdown containing locations. I like to store only the id of the selected location on the model and the locations in the viewbag, since is not needed to create a contact. I think that's the purpose of the viewbag.
For me the model is a bag or properties used in business operations, for example if I have a customer creation view using a NewCustomerModel, I don't wanna pollute my model with things like a IList<CustomerType> AND a SelectedCustomerTypeId property. I just want the second since is the one imma use to create the customer.
I am pretty new to this stuff but I am running into a concept-wall and I keep going back and forth with the best way to handle the problem.
I have a multi-view process to filling out a "New User Form". Each view has a small part of the entire form. In each view I have a model and the model has properties set to an instance of a LINQ to SQL class (for pre-populating) along with dropdown data (state, country). I also thought I should have a model (value object) that represents the entire form. This value object has properties for each LINQ class as well. So I made the view take the value object as a dependency injection. Then what? Just set a property to ViewData to send in multiple models? Seems like a bad idea since I would have to do that to every view. Should all view models come from a base class with the value object?
I might be way off already. Hopefully someone can help me get back on track. The ultimate goal is to have an object that represents the state/data of a form that spans multiple views and the form fields should populate if data is present.
Thanks for your patience!
Okay, so I am going to try to answer my own question but I am still not sure about things. I am going to use the info I got here: http://www.asp.net/Learn/mvc/tutorial-13-cs.aspx to create an instance of the value object that will be available to every view. Then I am sending the instance (or a property of) into the view model through it's constructor.
I am still working on how to keep the instance of the value object through all pages but I am assuming it will have to be done through a session variable of sorts.