Asp.Net MVC 2: How exactly does a view model bind back to the model upon post back? - asp.net-mvc-2

Sorry for the length, but a picture is worth 1000 words:
In ASP.NET MVC 2, the input form field "name" attribute must contain exactly the syntax below that you would use to reference the object in C# in order to bind it back to the object upon post back. That said, if you have an object like the following where it contains multiple Orders having multiple OrderLines, the names would look and work well like this (case sensitive):
This works:
Order[0].id
Order[0].orderDate
Order[0].Customer.name
Order[0].Customer.Address
Order[0].OrderLine[0].itemID // first order line
Order[0].OrderLine[0].description
Order[0].OrderLine[0].qty
Order[0].OrderLine[0].price
Order[0].OrderLine[1].itemID // second order line, same names
Order[0].OrderLine[1].description
Order[0].OrderLine[1].qty
Order[0].OrderLine[1].price
However we want to add order lines and remove order lines at the client browser. Apparently, the indexes must start at zero and contain every consecutive index number to N.
The black belt ninja Phil Haack's blog entry here explains how to remove the [0] index, have duplicate names, and let MVC auto-enumerate duplicate names with the [0] notation. However, I have failed to get this to bind back using a nested object:
This fails:
Order.id // Duplicate names should enumerate at 0 .. N
Order.orderDate
Order.Customer.name
Order.Customer.Address
Order.OrderLine.itemID // And likewise for nested properties?
Order.OrderLine.description
Order.OrderLine.qty
Order.OrderLine.price
Order.OrderLine.itemID
Order.OrderLine.description
Order.OrderLine.qty
Order.OrderLine.price
I haven't found any advice out there yet that describes how this works for binding back nested ViewModels on post. Any links to existing code examples or strict examples on the exact names necessary to do nested binding with ILists?
Steve Sanderson has code that does this sort of thing here, but we cannot seem to get this to bind back to nested objects. Anything not having the [0]..[n] AND being consecutive in numbering simply drops off of the return object.
Any ideas?

We found a work around, by using the following:
Html.EditorFor(m => m, "ViewNameToUse", "FieldPrefix")
Where FieldPrefix is the "object[0]". This is hardly ideal, but it certainly works pretty well. It's simple and elegant.

Related

jasper: listing all key-values pairs of a collection

In jasper I have to print a collection without knowing in advance the keys, because they are programmatic and can change over time. Let me do an example of this list:
formData[0]={addictions=1, workout=0, allergies=1, selfSufficiency=0}
formData[1]={gastricNose=1, weightChange=1, diet=XXXX}
[...]
formData[12]={dailyAmount=12, latestDate={type=date, value=1542582000000}, ostomy=1, ostomyType=AA, ostomyBag=BB}
How can I print a list of all these keys/values so that they get all listed properly like this? I can already print these objects raw in a list but they obviously look pretty much like the example I wrote above, while instead I need jasper to cycle through each of the elements by itself and retrieve the keys and the value for each element.
This is what I'm trying to print:
addictions: 1
workout: 0
[...]
gastricNose: 1
weightChange: 1
[...]
dailyAmount: 12
latestDate: 18/11/2018
[...]
In all posts I've looked into I'm required to know at least the name of the keys, but in my case I can't. And I cannot modify the data source structure either (for instance formatting the collection to be {key:"addictions",value:"1"} can't do that).
Thanks for your hints

Word 2010 can Field added via QuickParts be given an ID and later referenced in document.Fields collection

I need to add a few fields to a Word 2010 DOTX template which are to be populated automatically with custom content at "run time" when the document is opened in a C# program using Word Interop services. I don't see any way to assign a unique name to "Ask" or "Fill-In" fields when adding them to the template via the QuickParts ribbon-menu option.
When I iterate the document.Fields collection in the C# program, I must know which field I'm referencing, so it can be assigned the correct value.
It seems things have changed between previous versions of Word and Word 2010. So, if you answer please make sure your answer applies to 2010. Don't assume that what used to work in previous versions works in 2010. Much appreciated, since I rarely work with Word and feel like a dolt when trying to figure out the ribbon menuing in 2010.
You are correct in that fields don't necessarily have a built-in way to uniquely distinguish themselves from other field instances (other than its index in the Fields collection). However, you can use the Field.Type property to test for wdFieldAsk or wdFieldFillIn . If this is not narrow enough to ID then you will need to parse your own unique identifier from the Field.Code. For example, you can construct your FILLIN field as:
{ FILLIN "Hello, World!" MYIDENTIFER }
when you iterate through your document.Fields collection just have a test for the identifier being in the string. EDIT: example:
For Each fld In ActiveDocument.Fields
If InStr("CARMODEL", fld.Code) <> 0 Then
''this is the carmodel field
End If
Next
Another alternative - seek your specific field with a Find.Text for "^d MYIDENTIFIER" (where ^d is expression for 'field code')
Let me know if this helps and expand on your question if any gaps.

Data Processing, how to approach

I have the following Problem, given this XML Datastructure:
<level1>
<level2ElementTypeA></level2ElementTypeA>
<level2ElementTypeB>
<level3ElementTypeA>String1Ineed<level3ElementTypeB>
</level2ElementTypeB>
...
<level2ElementTypeC>
<level3ElementTypeB attribute1>
<level4ElementTypeA>String2Ineed<level4ElementTypeA>
<level3ElementTypeB>
<level2ElementTypeC>
...
<level2ElementTypeD></level2ElementTypeD>
</level1>
<level1>...</level1>
I need to create an Entity which contain: String1Ineed and String2Ineed.
So every time I came across a level3ElementTypeB with a certain value in attribute1, I have my String2Ineed. The ugly part is how to obtain String1Ineed, which is located in the first element of type level2ElementTypeB above the current level2ElementTypeC.
My 'imperative' solution looks like that that I always keep an variable with the last value of String1Ineed and if I hit criteria for String2Ineed, I simply use that. If we look at this from a plain collection processing point of view. How would you model the backtracking logic between String1Ineed and String2Ineed? Using the State Monad?
Isn't this what XPATH is for? You can find String2Ineed and then change the axis to search back for String1Ineed.

TermQuery not returning on a known search term, but WildcardQuery does

Am hoping someone with enough insight into the inner workings of Lucene might be able to point me in the right direction =)
I'll skip most of the surrounding irellevant code, and cut right to the chase. I have a Lucene index, to which I am adding the following field to the index (variables replaced by their literal values):
document.Add( new Field("Typenummer", "E5CEB501A244410EB1FFC4761F79E7B7",
Field.Store.YES , Field.Index.UN_TOKENIZED));
Later, when I search my index (using other types of queries), I am able to verify that this field does indeed appear in my index - like when looping through all Fields returned by Document.GetFields()
Field: Typenummer, Value: E5CEB501A244410EB1FFC4761F79E7B7
So far so good :-)
Now the real problem is - why can I not use a TermQuery to search against this value and actually get a result.
This code produces 0 hits:
// Returns 0 hits
bq.Add( new TermQuery( new Term( "Typenummer",
"E5CEB501A244410EB1FFC4761F79E7B7" ) ), BooleanClause.Occur.MUST );
But if I switch this to a WildcardQuery (with no wildcards), I get the 1 hit I expect.
// returns the 1 hit I expect
bq.Add( new WildcardQuery( new Term( "Typenummer",
"E5CEB501A244410EB1FFC4761F79E7B7" ) ), BooleanClause.Occur.MUST );
I've checked field lengths, I've checked that I am using the same Analyzer and so on and I am still on square 1 as to why this is.
Can anyone point me in a direction I should be looking?
I finally figured out what was going on. I'm expanding the tags for this question as it, much to my surprise, actually turned out to be an issue with the CMS this particular problem exists in. In summary, the problem came down to this:
The field is stored UN_TOKENIZED, meaning Lucene will store it excactly "as-is"
The BooleanQuery I pasted snippets from gets sent to the Sitecore SearchManager inside a PreparedQuery wrapper
The behaviour I expected from this was, that my query (having already been prepared) would go - unaltered - to the Lucene API
Turns out I was wrong. It passes through a RewriteQuery method that copies my entire set of nested queries as-is, with one exception - all the Term arguments are passed through a LowercaseStrategy()
As I indexed an UPPERCASE Term (UN_TOKENIZED), and Sitecore changes my PreparedQuery to lowercase - 0 results are returned
Am not going to start an argument of whether this is "by design" or "by design flaw" implementation of the Lucene Wrapper API - I'll just note that rewriting my query when using the PreparedQuery overload is... to me... unexpected ;-)
Further teachings from this; storing the field as TOKENIZED will eliminate this problem too, as the StandardAnalyzer by default will lowercase all tokens.

RESTful URL design for search

I'm looking for a reasonable way to represent searches as a RESTful URLs.
The setup: I have two models, Cars and Garages, where Cars can be in Garages. So my urls look like:
/car/xxxx
xxx == car id
returns car with given id
/garage/yyy
yyy = garage id
returns garage with given id
A Car can exist on its own (hence the /car), or it can exist in a garage. What's the right way to represent, say, all the cars in a given garage? Something like:
/garage/yyy/cars ?
How about the union of cars in garage yyy and zzz?
What's the right way to represent a search for cars with certain attributes? Say: show me all blue sedans with 4 doors :
/car/search?color=blue&type=sedan&doors=4
or should it be /cars instead?
The use of "search" seems inappropriate there - what's a better way / term? Should it just be:
/cars/?color=blue&type=sedan&doors=4
Should the search parameters be part of the PATHINFO or QUERYSTRING?
In short, I'm looking for guidance for cross-model REST url design, and for search.
[Update] I like Justin's answer, but he doesn't cover the multi-field search case:
/cars/color:blue/type:sedan/doors:4
or something like that. How do we go from
/cars/color/blue
to the multiple field case?
For the searching, use querystrings. This is perfectly RESTful:
/cars?color=blue&type=sedan&doors=4
An advantage to regular querystrings is that they are standard and widely understood and that they can be generated from form-get.
The RESTful pretty URL design is about displaying a resource based on a structure (directory-like structure, date: articles/2005/5/13, object and it's attributes,..), the slash / indicates hierarchical structure, use the -id instead.
Hierarchical structure
I would personaly prefer:
/garage-id/cars/car-id
/cars/car-id #for cars not in garages
If a user removes the /car-id part, it brings the cars preview - intuitive. User exactly knows where in the tree he is, what is he looking at. He knows from the first look, that garages and cars are in relation. /car-id also denotes that it belongs together unlike /car/id.
Searching
The searchquery is OK as it is, there is only your preference, what should be taken into account. The funny part comes when joining searches (see below).
/cars?color=blue;type=sedan #most prefered by me
/cars;color-blue+doors-4+type-sedan #looks good when using car-id
/cars?color=blue&doors=4&type=sedan #also possible, but & blends in with text
Or basically anything what isn't a slash as explained above.
The formula: /cars[?;]color[=-:]blue[,;+&], though I wouldn't use the & sign as it is unrecognizable from the text at first glance if that's your thing.
** Did you know that passing JSON object in URI is RESTful? **
Lists of options
/cars?color=black,blue,red;doors=3,5;type=sedan #most prefered by me
/cars?color:black:blue:red;doors:3:5;type:sedan
/cars?color(black,blue,red);doors(3,5);type(sedan) #does not look bad at all
/cars?color:(black,blue,red);doors:(3,5);type:sedan #little difference
possible features?
Negate search strings (!)
To search any cars, but not black and red:
?color=!black,!red
color:(!black,!red)
Joined searches
Search red or blue or black cars with 3 doors in garages id 1..20 or 101..103 or 999 but not 5
/garage[id=1-20,101-103,999,!5]/cars[color=red,blue,black;doors=3]
You can then construct more complex search queries. (Look at CSS3 attribute matching for the idea of matching substrings. E.g. searching users containing "bar" user*=bar.)
Conclusion
Anyway, this might be the most important part for you, because you can do it however you like after all, just keep in mind that RESTful URI represents a structure which is easily understood e.g. directory-like /directory/file, /collection/node/item, dates /articles/{year}/{month}/{day}.. And when you omit any of last segments, you immediately know what you get.
So.., all these characters are allowed unencoded:
unreserved: a-zA-Z0-9_.-~
Typically allowed both encoded and not, both uses are then equivalent.
special characters: $-_.+!*'(),
reserved: ;/?:#=&
May be used unencoded for the purpose they represent, otherwise they must be encoded.
unsafe: <>"#%{}|^~[]`
Why unsafe and why should rather be encoded: RFC 1738 see 2.2
Also see RFC 1738#page-20 for more character classes.
RFC 3986 see 2.2
Despite of what I previously said, here is a common distinction of delimeters, meaning that some "are" more important than others.
generic delimeters: :/?#[]#
sub-delimeters: !$&'()*+,;=
More reading:
Hierarchy: see 2.3, see 1.2.3
url path parameter syntax
CSS3 attribute matching
IBM: RESTful Web services - The basics
Note: RFC 1738 was updated by RFC 3986
Although having the parameters in the path has some advantages, there are, IMO, some outweighing factors.
Not all characters needed for a search query are permitted in a URL. Most punctuation and Unicode characters would need to be URL encoded as a query string parameter. I'm wrestling with the same problem. I would like to use XPath in the URL, but not all XPath syntax is compatible with a URI path. So for simple paths, /cars/doors/driver/lock/combination would be appropriate to locate the 'combination' element in the driver's door XML document. But /car/doors[id='driver' and lock/combination='1234'] is not so friendly.
There is a difference between filtering a resource based on one of its attributes and specifying a resource.
For example, since
/cars/colors returns a list of all colors for all cars (the resource returned is a collection of color objects)
/cars/colors/red,blue,green would return a list of color objects that are red, blue or green, not a collection of cars.
To return cars, the path would be
/cars?color=red,blue,green or /cars/search?color=red,blue,green
Parameters in the path are more difficult to read because name/value pairs are not isolated from the rest of the path, which is not name/value pairs.
One last comment. I prefer /garages/yyy/cars (always plural) to /garage/yyy/cars (perhaps it was a typo in the original answer) because it avoids changing the path between singular and plural. For words with an added 's', the change is not so bad, but changing /person/yyy/friends to /people/yyy seems cumbersome.
To expand on Peter's answer - you could make Search a first-class resource:
POST /searches # create a new search
GET /searches # list all searches (admin)
GET /searches/{id} # show the results of a previously-run search
DELETE /searches/{id} # delete a search (admin)
The Search resource would have fields for color, make model, garaged status, etc and could be specified in XML, JSON, or any other format. Like the Car and Garage resource, you could restrict access to Searches based on authentication. Users who frequently run the same Searches can store them in their profiles so that they don't need to be re-created. The URLs will be short enough that in many cases they can be easily traded via email. These stored Searches can be the basis of custom RSS feeds, and so on.
There are many possibilities for using Searches when you think of them as resources.
The idea is explained in more detail in this Railscast.
Justin's answer is probably the way to go, although in some applications it might make sense to consider a particular search as a resource in its own right, such as if you want to support named saved searches:
/search/{searchQuery}
or
/search/{savedSearchName}
I use two approaches to implement searches.
1) Simplest case, to query associated elements, and for navigation.
/cars?q.garage.id.eq=1
This means, query cars that have garage ID equal to 1.
It is also possible to create more complex searches:
/cars?q.garage.street.eq=FirstStreet&q.color.ne=red&offset=300&max=100
Cars in all garages in FirstStreet that are not red (3rd page, 100 elements per page).
2) Complex queries are considered as regular resources that are created and can be recovered.
POST /searches => Create
GET /searches/1 => Recover search
GET /searches/1?offset=300&max=100 => pagination in search
The POST body for search creation is as follows:
{
"$class":"test.Car",
"$q":{
"$eq" : { "color" : "red" },
"garage" : {
"$ne" : { "street" : "FirstStreet" }
}
}
}
It is based in Grails (criteria DSL): http://grails.org/doc/2.4.3/ref/Domain%20Classes/createCriteria.html
This is not REST. You cannot define URIs for resources inside your API. Resource navigation must be hypertext-driven. It's fine if you want pretty URIs and heavy amounts of coupling, but just do not call it REST, because it directly violates the constraints of RESTful architecture.
See this article by the inventor of REST.
In addition i would also suggest:
/cars/search/all{?color,model,year}
/cars/search/by-parameters{?color,model,year}
/cars/search/by-vendor{?vendor}
Here, Search is considered as a child resource of Cars resource.
There are a lot of good options for your case here. Still you should considering using the POST body.
The query string is perfect for your example, but if you have something more complicated, e.g. an arbitrary long list of items or boolean conditionals, you might want to define the post as a document, that the client sends over POST.
This allows a more flexible description of the search, as well as avoids the Server URL length limit.
RESTful does not recommend using verbs in URL's /cars/search is not restful. The right way to filter/search/paginate your API's is through Query Parameters. However there might be cases when you have to break the norm. For example, if you are searching across multiple resources, then you have to use something like /search?q=query
You can go through http://saipraveenblog.wordpress.com/2014/09/29/rest-api-best-practices/ to understand the best practices for designing RESTful API's
Though I like Justin's response, I feel it more accurately represents a filter rather than a search. What if I want to know about cars with names that start with cam?
The way I see it, you could build it into the way you handle specific resources:
/cars/cam*
Or, you could simply add it into the filter:
/cars/doors/4/name/cam*/colors/red,blue,green
Personally, I prefer the latter, however I am by no means an expert on REST (having first heard of it only 2 or so weeks ago...)
My advice would be this:
/garages
Returns list of garages (think JSON array here)
/garages/yyy
Returns specific garage
/garage/yyy/cars
Returns list of cars in garage
/garages/cars
Returns list of all cars in all garages (may not be practical of course)
/cars
Returns list of all cars
/cars/xxx
Returns specific car
/cars/colors
Returns lists of all posible colors for cars
/cars/colors/red,blue,green
Returns list of cars of the specific colors (yes commas are allowed :) )
Edit:
/cars/colors/red,blue,green/doors/2
Returns list of all red,blue, and green cars with 2 doors.
/cars/type/hatchback,coupe/colors/red,blue,green/
Same idea as the above but a lil more intuitive.
/cars/colors/red,blue,green/doors/two-door,four-door
All cars that are red, blue, green and have either two or four doors.
Hopefully that gives you the idea. Essentially your Rest API should be easily discoverable and should enable you to browse through your data. Another advantage with using URLs and not query strings is that you are able to take advantage of the native caching mechanisms that exist on the web server for HTTP traffic.
Here's a link to a page describing the evils of query strings in REST: http://web.archive.org/web/20070815111413/http://rest.blueoxen.net/cgi-bin/wiki.pl?QueryStringsConsideredHarmful
I used Google's cache because the normal page wasn't working for me here's that link as well:
http://rest.blueoxen.net/cgi-bin/wiki.pl?QueryStringsConsideredHarmful