Would it be possible to serialize a model object into a query string?
I've no idea if this is even possible, but if not, what is the best way to do this?
<% Html.RenderAction("Grid", "Grid", new { gridModel= ViewData["model"]}); %>
The Model is containing ca 20 properties, and creating the querystring with them in individually would make it a pain to work with and it would look really ugly. so what alternatives do I have?
To answer directly, you could use something like JSON.NET to serialize it to ASCII and then base64 encode it.
However, there are very real limits on how much data you can include in the query string and I'd hesitate to do this.
The closest thing I can think of would be to create a GUID, use that GUID as a key to store the object in Session, then pass the RenderAction the GUID. That action would pull the object out of the Session and then remove it from the Session.
Quick pseudocode (not guaranteed to even compile, much less work)
var _requestKey = Guid.NewGuid();
Session[requestKey] = gridModel;
Then on the other side:
var gridModel = Session[requestKey] as GridModelType;
Session[requestKey] = null;
I ended up using Form for this. Wasn't as pretty and nice as I wanted, but as far as I understand the only good way I could do it.
Related
In immutable.js what is the equivalent of an empty object?
My code is:
let iState = fromJS(state)
iState = iState.setIn(['ui', 'drafts'], {})
return iState.toJS()
But I think I should not use {} when using setIn. Please advise what I should use.
The best 'empty' data structure to use will depend on your use case (and I highly recommend looking at the other data structures and use their advantages) but for the most common interface/expected behavior and structure - Record will be the closest analog. That said, I also recommend looking into the Map data structure as it has a bit more functionality baked in than Record that you may find you need.
In the excellent mvvmcross-library I can use RIO binding to prevent unreadable code:
public INC<String>Title = new NC<String>();
Then I can read and write values using Title.Value. Makes the models much more readable.
Normally, this property would be written as:
private string _title;
public string Title
{
get { return _title; }
set
{
_title = value;
RaisePropertyChanged("Title");
}
}
But when I want to use sqlite-net, these fields cannot be streamed to the database because they are not basic types with a getter and setter.
I can think of a few options how to get around that:
Make a new simple object that is similar to the model, but only with
the direct db-fields. And create a simple import-export static
method on the model. This also could prevent struggling with complex
model-code that never needs to relate to the actual database.
Make sqlite-net understand reading NC-fields. I read into the code of the mapper, but it looks like this is going to be a lot of work because it relies on the getter-setter. I did not find a way to insert custom mapping to a type, that could be generic.
Remove RIO and just put in all the code myself instead of relying on RIO.
Maybe someone has some advice?
Thanks Stuart. It was exactly my thought, so I did implement it that way: my (DB) Models do not contain RIO. Only my viewmodels do, and they reference a Model that is DB-compatible.
So, for posterity the following tips:
- Do not use RIO in your models that need to be database-backed.
- Reference models in your viewmodels. In the binding you can use the . (dot) to reference this model.
This keeps them nicely separated. This gives you also another advantage: if you need to reuse a model (because the same object might be displayed twice on the screen), but under different circumstances, it is much easier to handle this situaties to find this already instantiated model.
I have an object in localStorage, something like:
{"one":"oneone","two":"twotwo"}
You get the picture.
For some reason attempting to add more items to the object won't work. If I want to add "three":"threethree", it ignores that and when I update the storage area in Opera Dragonfly it shows the same old object, unchanged...
Does anybody know how to append to objects on the fly? Or will I have to append to a copy of the object in my code, then clear the old object from localStorage, and store the updated one? I can see this being the only way, but it seems like it might be a bit ugly... Ideas please! :D
I think that the safest and cleanest way to do this is getting the object from localStorage, parsing it, add some data ans stringify it for storing.
Like you say, it is a bit ugly, but you can create a function to do this
function mergeLocalStorage(key, obj){
var newObj = JSON.parse(localStorage.getItem(key));
for (var k in obj){
newObj[k] = obj[k];
}
localStorage.setItem(key, JSON.stringify(newObj));
return newObj;
}
For a game I'm attempting to develop, I am writing a resource pool class in order to recycle objects without calling the "new" operator. I would like to be able to specify the size of the pool, and I would like it to be strongly typed.
Because of these considerations, I think that a Vector would be my best choice. However, as Vector is a final class, I can't extend it. So, I figured I'd use composition instead of inheritance, in this case.
The problem I'm seeing is this - I want to instantiate the class with two arguments: size and class type, and I'm not sure how to pass a type as an argument.
Here's what I tried:
public final class ObjPool
{
private var objects:Vector.<*>;
public function ObjPool(poolsize:uint, type:Class)
{
objects = new Vector.<type>(poolsize); // line 15
}
}
And here's the error I receive from FlashDevelop when I try to build:
\src\ObjPool.as(15): col: 18 Error: Access of undefined property type.
Does anybody know of a way to do this? It looks like the Flash compiler doesn't like to accept variable names within the Vector bracket notation. (I tried changing constructor parameter "type" to String as a test, with no results; I also tried putting a getQualifiedClassName in there, and that didn't work either. Untyping the objects var was fruitless as well.) Additionally, I'm not even sure if type "Class" is the right way to do this - does anybody know?
Thanks!
Edit: For clarification, I am calling my class like this:
var i:ObjPool = new ObjPool(5000, int);
The intention is to specify a size and a type.
Double Edit: For anyone who stumbles upon this question looking for an answer, please research Generics in the Java programming language. As of the time of this writing, they are not implemented in Actionscript 3. Good luck.
I have been trying to do this for a while now and Dominic Tancredi's post made me think that even if you can't go :
objects = new Vector.<classType>(poolsize);
You could go something like :
public final class ObjPool
{
private var objects:Vector.<*>;
public function ObjPool(poolsize:uint, type:Class)
{
var className : String = getQualifiedClassName(type);
var vectorClass : Class = Class(getDefinitionByName("Vector.<" + className + ">"));
objects = new vectorClass(poolsize);
}
}
I tried it with both int and a custom class and it seems to be working fine. Of course you would have to check if you actually gain any speed from this since objects is a Vector.<*> and flash might be making some implicit type checks that would negate the speed up you get from using a vector.
Hope this helps
This is an interesting question (+1!), mostly because I've never tried it before. It seems like from your example it is not possible, which I do find odd, probably something to do with how the compiler works. I question why you would want to do this though. The performance benefit of a Vector over an Array is mostly the result of it being typed, however you are explicitly declaring its type as undefined, which means you've lost the performance gain. So why not just use an array instead? Just food for though.
EDIT
I can confirm this is not possible, its an open bug. See here: http://bugs.adobe.com/jira/browse/ASC-3748 Sorry for the news!
Tyler.
It is good you trying to stay away from new but:
Everything I have ever read about Vector<> in actionscript says it must be strongly typed. So
this shouldn't work.
Edit: I am saying it can't be done.
Here see if this helps.
Is it possible to define a generic type Vector in Actionsctipt 3?
Shot in the dock, but try this:
var classType:Class = getDefinitionByName(type) as Class;
...
objects = new Vector.<classType>(poolsize); // line 15
drops the mic
I don't really see the point in using a Vector.<*>. Might as well go with Array.
Anyhow, I just came up with this way of dynamically create Vectors:
public function getCopy (ofVector:Object):Object
{
var copy:Object = new ofVector.constructor;
// Do whatever you like with the vector as long as you don't need to know the type
return copy;
}
This really is an architectural question. I feel like I'm going about this the wrong way and wanted some input on best practices.
Let's say I have a Transactions table and a TransactionTypes table. Views will submit the appropriate transaction data which is processed in my controller. The problem is that the logic in the controller may be a bit complex and the TransactionType is not provided by the view inputs, but computed in the controller. (Which may be part of my problem).
For example, let's say that the View submits a ViewModel that would map to a TransactionType of "Withdrawal". However, the controller detects that it needs to change this to an Overdraft" as funds aren't sufficient. What I don't want to do is this:
transaction.TypeId =
DataContext.TransactionTypes.Single(x => x.type == "Overdraft").id;
... as I'll be embedding string literals in my code. Right?
OK, so I could map the values to strong types that would allow me to do this:
class TranTypes
{
public const long Deposit = 1;
public const long Withdrawal = 2;
public const long Overdraft = 3;
}
...
transaction.TypeId =
DataContext.TransactionTypes.Single(x => x.id == TranTypes.Overdraft);
Now, if my lookups change in the DB, I have one place that I can update the mappings and my controllers still have insight into the model.
But this feels awkward too.
I feel like what I really want is for the Linq To SQL auto-code generation to be able to generate the association so I can just refer to strongly-typed names (Deposit, Withdrawal, and Draft) and be assured that it will always return the current values for these in the database. Changes made to the lookup table during runtime would result in problems, but it still seems so much cleaner.
What should I be digesting to understand how best to structure this?
Thanks in advance for enlarging my brain. :-)
Dont worry about whether you have an embedded string or a strongy typed value - either is perfectly acceptable - which ever makes sense fror your database design.
What you should do, however, is write a single routine in a repository or helper class that you can then call from whatever controller or action requires it - if anything changes there is only one place to make the change.
One simple approach I've always liked is the Enum approach.
public enum TransactionType {
Overdraft
}
transaction.TypeId =
DataContext.TransactionTypes.Single(x => x.type == TransactionType.Overdraft.ToString()).id;
It's pretty simple, but I like it.
A more sophisticated approach (not sure if this works with Linq to SQL, but more sophisticated ORMs support it (like EF, DO .NET, LLBLGen, etc.) is to use inheritance in your data model, with discriminators.
That is, have a subclass of TransactionType called OverdraftTransactionType with a discriminator (the key) that identifies different types of TransactionTypes from each other.
Random link:
http://weblogs.asp.net/zeeshanhirani/archive/2008/08/16/single-table-inheritance-in-entity-framework.aspx