Cast ActionScript Object to Model - model-view-controller

Is there any "automatic way" to casts an "Object" to a personalized Model Data Type in ActionScript 3?
Example:
package Example{
public class ExampleModel{
private _id:int;
private _randomAttribute:String;
public function ExampleModel(){
_id = 0;
_randomAttribute = "";
}
public function get id():int{
return _id;
}
public function set id(value:int):void{
_id = value;
}
public function get randomAttribute():String{
return _randomAttribute;
}
public function set randomAttribute(value:String):void{
_randomAttribute = value;
}
}
}
Then, in some part of my code, lets assume that I have something like this:
var _obj:Object = new Object();
_obj.id = 1;
obj.randomAttribute = "Hello World";
What I want would be something like:
var _exampleModel:ExampleModel = obj as ExampleModel;
But when I do this, the result on _exampleModel is null.
Any ideas?
Thanks.
EDIT:
According to Manish's answer, all I changed was the type of p var, which allows me to go through every kind of attribute:
public function fromObject(obj:Object):void{
//p:* includes every type of attributes.
for (var p:* in obj)
if (this.hasOwnProperty(p))
// Set private var directly.
this["_" + p] = obj[p];
}
Thanks Manish and rcdmk.
Manish's answer was enough for me and according to rcdmk's comment, the p:String isn't about the Type of data that the loop will go through, it is actually the name of the property, which makes sense because every name is a String.

The only way to automatically "cast" it is the following:
var model:Model = new Model();
var obj:Object = { id: "98123", name: "John Doe" };
for (var p:String in obj) {
if (model.hasOwnProperty(p))
model[p] = obj[p];
}
(Note: Model.id and Model.name are both type String in my example.)
A more proper way to do it, of course, is to pass the plain object to the Model object and let the Model object absorb it.
var model:Model = new Model(obj);
Or:
var model:Model = new Model();
model.fromObject(obj);
Where in the Model code you have:
public function Model(obj:Object = null)
{
if (obj != null)
fromObject(obj);
}
public function fromObject(obj:Object):void
{
for (var p:String in obj)
if (this.hasOwnProperty(p))
// Set private var directly.
this["_" + p] = obj[p];
}
This code can be in your abstract base Model class, and all your specific Model subclasses (e.g. ProductModel, CustomerModel, etc.) can use it automatically.
e.g.
public class ProductModel extends Model
{
public function ProductModel(obj:Object = null)
{
super(obj);
}
}

Related

How to select multiple class properties in LINQ Expression?

If I have a class like this
`
class Person
{
public string First;
public string Last;
public bool IsMarried;
public int Age;
}`
Then how can I write a LINQ Expression where I could select properties of a Person. I want to do something like this (user can enter 1..n properties)
SelectData<Person>(x=>x.First, x.Last,x.Age);
What would be the input expression of my SelectData function ?
SelectData(Expression<Func<TEntity, List<string>>> selector); ?
EDIT
In my SelectData function I want to extract property names and then generate SELECT clause of my SQL Query dynamically.
SOLUTION
Ok, so what I have done is to have my SelectData as
public IEnumerable<TEntity> SelectData(Expression<Func<TEntity, object>> expression)
{
NewExpression body = (NewExpression)expression.Body;
List<string> columns = new List<string>();
foreach(var arg in body.Arguments)
{
var exp = (MemberExpression)arg;
columns.Add(exp.Member.Name);
}
//build query
And to use it I call it like this
ccc<Person>().SelectData(x => new { x.First, x.Last, x.Age });
Hopefully it would help someone who is looking :)
Thanks,
IY
I think it would be better to use delegates instead of Reflection. Apart from the fact that delegates will be faster, the compiler will complain if you try to fetch property values that do not exist. With reflection you won't find errors until run time.
Luckily there is already something like that. it is implemented as an extension function of IEnumerable, and it is called Select (irony intended)
I think you want something like this:
I have a sequence of Persons, and I want you to create a Linq
statement that returns per Person a new object that contains the
properties First and Last.
Or:
I have a sequence of Persns and I want you to create a Linq statement
that returns per Person a new object that contains Age, IsMarried,
whether it is an adult and to make it difficult: one Property called
Name which is a combination of First and Last
The function SelectData would be something like this:
IEnumerable<TResult> SelectData<TSource, TResult>(this IEnumerable<TSource> source,
Func<TSource, TResult> selector)
{
return source.Select(selector);
}
Usage:
problem 1: return per Person a new object that contains the
properties First and Last.
var result = Persons.SelectData(person => new
{
First = person.First,
Last = person.Last,
});
problem 2: return per Person a new object that contains Age, IsMarried, whether he is an adult and one Property called Name which is a combination
of First and Last
var result = Persons.SelectData(person => new
{
Age = person.Name,
IsMarried = person.IsMarried,
IsAdult = person.Age > 21,
Name = new
{
First = person.First,
Last = person.Last,
},
});
Well let's face it, your SelectData is nothing more than Enumerable.Select
You could of course create a function where you'd let the caller provide a list of properties he wants, but (1) that would limit his possibilities to design the end result and (2) it would be way more typing for him to call the function.
Instead of:
.Select(p => new
{
P1 = p.Property1,
P2 = p.Property2,
}
he would have to type something like
.SelectData(new List<Func<TSource, TResult>()
{
p => p.Property1, // first element of the property list
p -> p.Property2, // second element of the property list
}
You won't be able to name the returned properties, you won't be able to combine several properties into one:
.Select(p => p.First + p.Last)
And what would you gain by it?
Highly discouraged requirement!
You could achive similar result using Reflection and Extension Method
Model:
namespace ConsoleApplication2
{
class Person
{
public string First { get; set; }
public string Last { get; set; }
public bool IsMarried { get; set; }
public int Age { get; set; }
}
}
Service:
using System.Collections.Generic;
using System.Linq;
namespace Test
{
public static class Service
{
public static IQueryable<IQueryable<KeyValuePair<string, object>>> SelectData<T>(this IQueryable<T> queryable, string[] properties)
{
var queryResult = new List<IQueryable<KeyValuePair<string, object>>>();
foreach (T entity in queryable)
{
var entityProperties = new List<KeyValuePair<string, object>>();
foreach (string property in properties)
{
var value = typeof(T).GetProperty(property).GetValue(entity);
var entityProperty = new KeyValuePair<string, object>(property, value);
entityProperties.Add(entityProperty);
}
queryResult.Add(entityProperties.AsQueryable());
}
return queryResult.AsQueryable();
}
}
}
Usage:
using System;
using System.Collections.Generic;
using System.Linq;
namespace Test
{
class Program
{
static void Main(string[] args)
{
var list = new List<Person>()
{
new Person()
{
Age = 18,
First = "test1",
IsMarried = false,
Last = "test2"
},
new Person()
{
Age = 40,
First = "test3",
IsMarried = true,
Last = "test4"
}
};
var queryableList = list.AsQueryable();
string[] properties = { "Age", "Last" };
var result = queryableList.SelectData(properties);
foreach (var element in result)
{
foreach (var property in element)
{
Console.WriteLine($"{property.Key}: {property.Value}");
}
}
Console.ReadKey();
}
}
}
Result:
Age: 18
Last: test2
Age: 40
Last: test4

Use common linq expression to avoid duplicate of entity to poco

How may I avoid to duplicate the code I use for mapping a database entity to a poco object?
Given this code:
private IQueryable<DummyExtended> Find()
{
return (from dt in Entities.dummy_table
select new DummyExtended
{
Description = dt.table_1.table_2.description,
Dummy = new Dummy
{
Name = d.name,
Notes = d.notes,
HelpText = d.help_text
}
}).AsQueryable();
}
Can I create a common linq expression to be re-used for both methods?
private IQueryable<DummyExtended> Find()
{
return (from dt in Entities.dummy_table
select new DummyExtended
{
Description = dt.table_1.table_2.description,
Dummy = ...???
}).AsQueryable();
}
private IQueryable<DummyAlsoExtended> FindAnother()
{
return (from dt in Entities.dummy_table
select new DummyAlsoExtended
{
InnerHtml = dt.table_html.description,
Dummy = ....??
}).AsQueryable();
}
Example:
public static Expression<Func<dummy_table, Dummy>> EntityToPoco()
{
return d => new Dummy
{
Name = d.name,
Notes = d.notes,
HelpText = d.help_text
};
}
I can't quite get it right
....
Dummy = ExtensionClass.EntityToPoco()
So you have a dummy_table which is a Enumerable or Queryable sequence of objects. Let's assume that the sequence contains objects of class DummyTableElement.
You showed, that if you have a DummyTableElement you know how to convert it into a Dummy object. You want to reuse this function to create other objects like DummyExtended and DummyAlsoExtended. If you want to do this LINQ-alike, it is best to create extension functions for it:
static class DummyTableElementExtensions
{
public static Dummy ToDummy(this TableElement tableElement)
{
return new Dummy()
{
Name = tableElement.name,
Notes = tableElement.notes,
HelpText = tableElement.help_text
};
}
}
Once you have this, you can create similar functions to convert TableElements into DummyExtended and DummyAlsoExtended. They will be one-liners.
In the same extension class:
public static DummyExtended ToDummyExtended(this TableElement tableElement)
{
return new DummyExtended()
{
Description = tableElement.table_1.table_2.description,
Dummy = tableElement.ToDummy(),
};
}
public static DummyAlsoExtended ToDummyAlsoExtended(this TableElement tableElement)
{
return new DummyAlsoExtended
{
InnerHtml = tableElement.table_html.description,
Dummy = tableElement.ToDummy(),
};
}
And once you've got these, you can create extension functions to convert any IQueryable of TableElements:
public static IQueryable<DummyExtended> ToDummyExtended(
this IQueryable<TableElement> tableElements)
{
return tableElements
.Select(tableElement => tableelement.ToDummyExtended();
}
And a similar one-line function for DummyAlsoExtended.
Your Find function and FindAnother function will also be one-liners:
private IQueryable<DummyExtended> Find()
{
return dummy_table.ToDummyExtended();
}
private IQueryable<DummyAlsoExtended> FindAnother()
{
return dummy_table.ToDummyAlsoExtended();
}
I'm not sure why you wanted to use an expression in this. It doesn't seem that DummyExtended and DummyAlsoExtended are really similar, except that they both have a property Dummy.
One reason to parameterize the destination of your find function could be because you want to create anonymous classes in your Find function.
Again, once you've created ToDummy this will be a one-liner:
public static IQueryable<TResult> Find<TSource, TResult>(
this IQueryable<TSource> source,
Expression<Func<TSource, TResult>> resultSelector)
{
return source.Select(sourceElement => resultSelector(sourceElement);
}
Usage would be:
var X = dummy_Table.find(tableElement => new
{
foo = tableElement.CalculateFoo(),
bar = tableElement.CalculateBar(),
Dummy = tableElement.ToDummy(),
});

Trying to save comma-separated list

Trying to save selections from a CheckBoxList as a comma-separated list (string) in DB (one or more choices selected). I am using a proxy in order to save as a string because otherwise I'd have to create separate tables in the DB for a relation - the work is not worth it for this simple scenario and I was hoping that I could just convert it to a string and avoid that.
The CheckBoxList uses an enum for it's choices:
public enum Selection
{
Selection1,
Selection2,
Selection3
}
Not to be convoluted, but I use [Display(Name="Choice 1")] and an extension class to display something friendly on the UI. Not sure if I can save that string instead of just the enum, although I think if I save as enum it's not a big deal for me to "display" the friendly string on UI on some confirmation page.
This is the "Record" class that saves a string in the DB:
public virtual string MyCheckBox { get; set; }
This is the "Proxy", which is some sample I found but not directly dealing with enum, and which uses IEnumerable<string> (or should it be IEnumerable<Selection>?):
public IEnumerable<string> MyCheckBox
{
get
{
if (String.IsNullOrWhiteSpace(Record.MyCheckBox)) return new string[] { };
return Record
.MyCheckBox
.Split(new[] { ',' }, StringSplitOptions.RemoveEmptyEntries)
.Select(r => r.Trim())
.Where(r => !String.IsNullOrEmpty(r));
}
set
{
Record.MyCheckBox = value == null ? null : String.Join(",", value);
}
}
To save in the DB, I am trying to do this in a create class:
proxy.MyCheckBox = record.MyCheckBox; //getting error here
but am getting the error:
Cannot implicitly convert 'string' to System.Collections.Generic.IEnumerable'
I don't know, if it's possible or better, to use Parse or ToString from the API for enum values.
I know that doing something like this will store whatever I put in the ("") into the DB, so it's just a matter of figuring out how to overcome the error (or, if there is an alternative):
proxy.MyCheckBox = new[] {"foo", "bar"};
I am not good with this stuff and have just been digging and digging to come up with a solution. Any help is much appreciated.
You can accomplish this using a custom user type. The example below uses an ISet<string> on the class and stores the values as a delimited string.
[Serializable]
public class CommaDelimitedSet : IUserType
{
const string delimiter = ",";
#region IUserType Members
public new bool Equals(object x, object y)
{
if (ReferenceEquals(x, y))
{
return true;
}
var xSet = x as ISet<string>;
var ySet = y as ISet<string>;
if (xSet == null || ySet == null)
{
return false;
}
// compare set contents
return xSet.Except(ySet).Count() == 0 && ySet.Except(xSet).Count() == 0;
}
public int GetHashCode(object x)
{
return x.GetHashCode();
}
public object NullSafeGet(IDataReader rs, string[] names, object owner)
{
var outValue = NHibernateUtil.String.NullSafeGet(rs, names[0]) as string;
if (string.IsNullOrEmpty(outValue))
{
return new HashSet<string>();
}
else
{
var splitArray = outValue.Split(new[] {Delimiter}, StringSplitOptions.RemoveEmptyEntries);
return new HashSet<string>(splitArray);
}
}
public void NullSafeSet(IDbCommand cmd, object value, int index)
{
var inValue = value as ISet<string>;
object setValue = inValue == null ? null : string.Join(Delimiter, inValue);
NHibernateUtil.String.NullSafeSet(cmd, setValue, index);
}
public object DeepCopy(object value)
{
// return new ISet so that Equals can work
// see http://www.mail-archive.com/nhusers#googlegroups.com/msg11054.html
var set = value as ISet<string>;
if (set == null)
{
return null;
}
return new HashSet<string>(set);
}
public object Replace(object original, object target, object owner)
{
return original;
}
public object Assemble(object cached, object owner)
{
return DeepCopy(cached);
}
public object Disassemble(object value)
{
return DeepCopy(value);
}
public SqlType[] SqlTypes
{
get { return new[] {new SqlType(DbType.String)}; }
}
public Type ReturnedType
{
get { return typeof(ISet<string>); }
}
public bool IsMutable
{
get { return false; }
}
#endregion
}
Usage in mapping file:
Map(x => x.CheckboxValues.CustomType<CommaDelimitedSet>();

How to generate a link to an HTTP POST action with Hyprlinkr?

I'm trying to use Hyprlinkr to generate URL to the HTTP Post action. My controller looks like this:
public class MyController : ApiController {
[HttpPost]
public void DoSomething([FromBody]SomeDto someDto) {
...
}
}
with this route:
routes.MapHttpRoute(
name: "MyRoute",
routeTemplate: "dosomething",
defaults: new { controller = "My", action = "DoSomething" });
I expect to get a simple URL: http://example.com/dosomething, but it does not work. I tried two methods:
1) routeLinker.GetUri(c => c.DoSomething(null)) - throws NullReferenceException
2) routeLinker.GetUri(c => c.DoSomething(new SomeDto())) - generates invalid URL:
http://example.com/dosomething?someDto=Namespace.SomeDto
Update:
Issue opened at github:
https://github.com/ploeh/Hyprlinkr/issues/17
I found a workaround, loosely based on Mark's answer. The idea is to go over every route parameter and remove those that have [FromBody] attribute applied to them. This way dispatcher does not need to be modified for every new controller or action.
public class BodyParametersRemover : IRouteDispatcher {
private readonly IRouteDispatcher _defaultDispatcher;
public BodyParametersRemover(String routeName) {
if (routeName == null) {
throw new ArgumentNullException("routeName");
}
_defaultDispatcher = new DefaultRouteDispatcher(routeName);
}
public Rouple Dispatch(
MethodCallExpression method,
IDictionary<string, object> routeValues) {
var routeKeysToRemove = new HashSet<string>();
foreach (var paramName in routeValues.Keys) {
var parameter = method
.Method
.GetParameters()
.FirstOrDefault(p => p.Name == paramName);
if (parameter != null) {
if (IsFromBodyParameter(parameter)) {
routeKeysToRemove.Add(paramName);
}
}
}
foreach (var routeKeyToRemove in routeKeysToRemove) {
routeValues.Remove(routeKeyToRemove);
}
return _defaultDispatcher.Dispatch(method, routeValues);
}
private Boolean IsFromBodyParameter(ParameterInfo parameter) {
var attributes = parameter.CustomAttributes;
return attributes.Any(
ct => ct.AttributeType == typeof (FromBodyAttribute));
}
}
The second option is the way to go:
routeLinker.GetUri(c => c.DoSomething(new SomeDto()))
However, when using a POST method, you'll need to remove the model part of the generated URL. You can do that with a custom route dispatcher:
public ModelFilterRouteDispatcher : IRouteDispatcher
{
private readonly IRouteDispatcher defaultDispatcher;
public ModelFilterRouteDispatcher()
{
this.defaultDispatcher = new DefaultRouteDispatcher("DefaultApi");
}
public Rouple Dispatch(
MethodCallExpression method,
IDictionary<string, object> routeValues)
{
if (method.Method.ReflectedType == typeof(MyController))
{
var rv = new Dictionary<string, object>(routeValues);
rv.Remove("someDto");
return new Rouple("MyRoute", rv);
}
return this.defaultDispatcher.Dispatch(method, routeValues);
}
}
Now pass that custom dispatcher into your RouteLinker instance.
Caveat: it's very late as I'm writing this and I haven't attempted to compile the above code, but I thought I'd rather throw an attempted answer here than have you wait several more days.
Dimitry's solution got me most of the way to where I wanted, however the routeName ctor param was a problem because StructureMap doesn't know what to put in there. Internally hyprlink is using UrlHelper to generate the URI, and that wants to know the route name to use
At that point, I see why URI generation is so tricky, because it is tied to the route names in the routing config and in order to support POST, we need to associate the method, with the correct routename and that is not known at dispatcher ctor time. Default hyprlinkr assumes there is only one route config named "DefaultRoute"
I changed Dimitry's code as follows, and adopted a convention based approach, where controller methods that start with "Get" are mapped to the route named "Get" and controller methods starting with "Add" are mapped to the route named "Add".
I wonder if there are better ways of associating a method with the proper named routeConfig?
public class RemoveFromBodyParamsRouteDispatcher : IRouteDispatcher
{
private static readonly ILog _log = LogManager.GetLogger(typeof (RemoveFromBodyParamsRouteDispatcher));
public Rouple Dispatch(MethodCallExpression method,
IDictionary<string, object> routeValues)
{
var methodName = method.Method.Name;
DefaultRouteDispatcher defaultDispatcher;
if (methodName.StartsWith("Get"))
defaultDispatcher = new DefaultRouteDispatcher("Get");
else if (methodName.StartsWith("Add"))
defaultDispatcher = new DefaultRouteDispatcher("Add");
else
throw new Exception("Unable to determine correct route name for method with name " + methodName);
_log.Debug("Dispatch methodName=" + methodName);
//make a copy of routeValues as contract says we should not modify
var routeValuesWithoutFromBody = new Dictionary<string, object>(routeValues);
var routeKeysToRemove = new HashSet<string>();
foreach (var paramName in routeValuesWithoutFromBody.Keys)
{
var parameter = method.Method
.GetParameters()
.FirstOrDefault(p => p.Name == paramName);
if (parameter != null)
if (IsFromBodyParameter(parameter))
{
_log.Debug("Dispatch: Removing paramName=" + paramName);
routeKeysToRemove.Add(paramName);
}
}
foreach (var routeKeyToRemove in routeKeysToRemove)
routeValuesWithoutFromBody.Remove(routeKeyToRemove);
return defaultDispatcher.Dispatch(method, routeValuesWithoutFromBody);
}
private static bool IsFromBodyParameter(ParameterInfo parameter)
{
//Apparently the "inherit" argument is ignored: http://msdn.microsoft.com/en-us/library/cwtf69s6(v=vs.100).aspx
const bool msdnSaysThisArgumentIsIgnored = true;
var attributes = parameter.GetCustomAttributes(msdnSaysThisArgumentIsIgnored);
return attributes.Any(ct => ct is FromBodyAttribute);
}
}

return list from linq function

I want to return list of typenames from the class ApplicaitonType but i recieve error
Error 1 Instance argument: cannot convert from 'System.Linq.IQueryable' to 'System.Collections.Generic.IEnumerable' C:\Users\sharaman\documents\visual studio 2010\Projects\IssueTracking\BAL_IssueTracking\AppQuery.cs 19 17 BAL_IssueTracking
Please provide your feed back on it...much appericated
public static List AppType()
{
List<ApplicationType> m = new List<ApplicationType>();
var context = new Dll_IssueTracking.IssuTrackingEntities();// Object context defined in Dll_IssuTracking DLL
var query = from c in context.ApplicationTypes//Query to find TypeNames
select new { c.TypeName };
//return query.ToList<ApplicationType>();
m = query.ToList<ApplicationType>();//Error here
return m;
}
Your query selects a sequence of an anonymous type:
select new { c.TypeName };
It's not clear how you're expecting to turn that anonymous type into an ApplicationType.
Given your data source name, I'd expect the method to be as simple as:
public static List<ApplicationType> AppType()
{
using (var context = new Dll_IssueTracking.IssuTrackingEntities())
{
return context.ApplicationTypes.ToList();
}
}
In particular, it's pointless to create an instance of List<ApplicationType> and then ignore it, as you currently do:
List<ApplicationType> m = new List<ApplicationType>();
...
m = query.ToList<ApplicationType>();
return m;
Why would you bother with the variable here, and why would you assign a value to it which you never use?
EDIT: From your comment:
Actually I need to return TypeNames from ApplicaitonType class and bind to Dropdownlist through this function
That suggests your method is declared inappropriately. Either you can return a List<ApplicationType> and specify TypeName as the display part in the data binding, or you can change your method to return a List<string> (assuming that's the type of TypeName):
public static List<string> GetApplicationTypeNames()
{
using (var context = new Dll_IssueTracking.IssuTrackingEntities())
{
return context.ApplicationTypes.Select(type => type.typeName)
.ToList();
}
}
try with this code
public static List<ApplicationType> AppType()
{
var context = new Dll_IssueTracking.IssuTrackingEntities();// Object context defined in Dll_IssuTracking DLL
var query = from c in context.ApplicationTypes//Query to find TypeNames
select new ApplicationType{TypeName = c.TypeName };
return query.ToList();
}

Resources