I have a node and this node contains 5 childnodes. three of them is RatePlan. How can i select those RatePlan childnodes with LINQ?
Lets clarify something :
my xml is like this :
<hotels>
<hotel id="1" name="hotel 1">
<telephone>123456789</telephone>
<fax>123</fax>
<address>hotels address</address>
<hotelRatePlan>10</hotelRatePlan>
<hotelRatePlan>11</hotelRatePlan>
<hotelRatePlan>12</hotelRatePlan>
</hotel>
<hotel id="2" name="hotel 2">
<telephone>123456789</telephone>
<fax>123</fax>
<address>hotels address</address>
<hotelRatePlan>100</hotelRatePlan>
<hotelRatePlan>110</hotelRatePlan>
<hotelRatePlan>120</hotelRatePlan>
</hotel>
<hotel id="3" name="hotel 3">
<telephone>123456789</telephone>
<fax>123</fax>
<address>hotels address</address>
<hotelRatePlan>10</hotelRatePlan>
<hotelRatePlan>11</hotelRatePlan>
<hotelRatePlan>12</hotelRatePlan>
</hotel>
</hotels>
I am using XMLDocument to read XML file. After i read it i make a selection with SelectNodes. When i get first hotel information i want to select specific childnodes (hotelRatePlan). How can i do that?
Your question isn't particularly clear, but you might just want:
var ratePlans = node.Elements("RatePlan");
That's assuming you're actually using LINQ to XML rather than XmlNode, XmlDocument etc. If you are using the "old" DOM API, you could use:
var ratePlans = node.ChildNodes
.OfType<XmlElement>()
.Where(e => e.LocalName == "RatePlan");
... but I'd moving to LINQ to XML if you can. It's simply a much nicer XML API.
If you are sure that you will only have three rate plans per hotel, then you can load a hotel into an object of type Hotel like so:
XDocument data = XDocument.Load(yourXMLFileNameHere);
//if you have a namespace defined:
XNamespace ns = data.Root.Name.Namespace;
List<Hotels> hotels = (from item in data.Descendants(ns + "hotel")
select new Hotel
{
Id=Convert.ToInt32(item.Attribute("id").Value),
Name=item.Attribute("name").Value,
Telephone=item.Element(ns+"telephone").Value,
Fax=item.Element(ns+"fax").Value,
Address=item.Element(ns+"address").Value,
RatePlan1=item.Element(ns+"hotelRatePlan1").Value,
RatePlan2=item.Element(ns+"hotelRatePlan2").Value,
RatePlan3=item.Element(ns+"hotelRatePlan3").Value
}).ToList<Hotels>();
And then you reference your first rate plan in the following way:
string ratePlan1=hotels[0].RatePlan1;
If the number of your rate plans will vary, you can merge them together into a string like so:
<hotelRatePlans>10 20 30</hotelRatePlans>
Then you change the way you extract your rate plans, and when you need the actual plans, you use the String.Split method to get the array of individual plans.
I think you mean:
var ratePlans = node.ChildNodes.OfType<RatePlan>();
Related
I've the following Entity Model : Employee has a Company and a Company has Employees.
When using the Include statement like below:
var query = context.Employees.Include(e => e.Company);
query.Dump();
All related data is retrieved from the database correctly. (Using LEFT OUTER JOIN on Company table)
The problem is hat when I use the GroupBy() from System.Linq.Dynamic to group by Company.Name, the Employees are missing the Company data because the Include is lost.
Example:
var groupByQuery = query.GroupBy("new (Company.Name as CompanyName)", "it");
groupByQuery.Dump();
Is there a way to easily retrieve the applied Includes on the 'query' as a string collection, so that I can include them in the dynamic GroupBy like this:
var groupByQuery2 = query.GroupBy("new (Company, Company.Name as CompanyName)", "it");
groupByQuery2.Dump();
I thought about using the ToString() functionality to get the SQL Command like this:
string sql = query.ToString();
And then use RegEx to extract all LEFT OUTER JOINS, but probably there is a better solution ?
if you're creating the query in the first place - I'd always opt to save the includes (and add to them if you're making a composite query/filtering).
e.g. instead of returning just 'query' return new QueryContext {Query = query, Includes = ...}
I'd like to see a more elegant solution - but I think that's your best bet.
Otherwise you're looking at expression trees, visitors and all those nice things.
SQL parsing isn't that straight either - as queries are not always that simple (often a combo of things etc.).
e.g. there is a `span' inside the query object (if you traverse a bit) which seems to be holding the 'Includes' but it's not much help.
I'm trying to use linq to objects with html agility pack to join two result sets on their relative ordinal position. One set is a list of headers, the other is a set of tables, with each table corresponding to one of the header values. Each set has a count of five. I've read the post here which looks very similar, but can't get it to translate to my purposes.
Here is what I'm using to get the two html node collections:
HtmlNodeCollection ratingsChgsHdrs = htmlDoc.DocumentNode.SelectNodes("//div[#id='calendar-header']");
HtmlNodeCollection ratingsChgsTbls = htmlDoc.DocumentNode.SelectNodes("//table[#class='calendar-table']");
The collection ratingsChgsHdrs contains the headers for each of the tables in ratingsChgsTbls, within the InnerText property. The end result I'm looking for is one result set consisting of all of the rows from all five tables, with the header value added as a property to each row. I hope that is clear.. any help would be great.
This might work:
ratingsChgsHdrs.Select((x, i) => new { x, ratingsChgsTbls.ElementAt(i) });
I have an Abstract type called Product, and five "Types" that inherit from Product in a table per type hierarchy fashion as below:
I want to get all of the information for all of the Products, including a smattering of properties from the different objects that inherit from products to project them into a new class for use in an MVC web page. My linq query is below:
//Return the required products
var model = from p in Product.Products
where p.archive == false && ((Prod_ID == 0) || (p.ID == Prod_ID))
select new SearchViewModel
{
ID = p.ID,
lend_name = p.Lender.lend_name,
pDes_rate = p.pDes_rate,
pDes_details = p.pDes_details,
pDes_totTerm = p.pDes_totTerm,
pDes_APR = p.pDes_APR,
pDes_revDesc = p.pDes_revDesc,
pMax_desc = p.pMax_desc,
dDipNeeded = p.dDipNeeded,
dAppNeeded = p.dAppNeeded,
CalcFields = new DAL.SearchCalcFields
{
pDes_type = p.pDes_type,
pDes_rate = p.pDes_rate,
pTFi_fixedRate = p.pTFi_fixedRate
}
}
The problem I have is accessing the p.pTFi_fixedRate, this is not returned with the Products collection of entities as it is in the super type of Fixed. How do I return the "super" type of Products (Fixed) properties using Linq and the Entity Framework. I actually need to return some fields from all the different supertypes (Disc, Track, etc) for use in calculations. Should I return these as separate Linq queries checking the type of "Product" that is returned?
This is a really good question. I've had a look in the Julie Lerman book and scouted around the internet and I can't see an elegant answer.
If it were me I would create a data transfer object will all the properties of the types and then have a separate query for each type and then union them all up. I would insert blanks into the DTO properies where the properties aren't relevant to that type. Then I would hope that the EF engine makes a reasonable stab at creating decent SQL.
Example
var results = (from p in context.Products.OfType<Disc>
select new ProductDTO {basefield1 = p.val1, discField=p.val2, fixedField=""})
.Union(
from p in context.Products.OfType<Fixed>
select new ProductDTO {basefield1 = p.val1, discField="", fixedField=p.val2});
But that can't be the best answer can it. Is there any others?
So Fixed is inherited from Product? If so, you should probably be querying for Fixed instead, and the Product properties will be pulled into it.
If you are just doing calculations and getting some totals or something, you might want to look at using a stored procedure. It will amount to fewer database calls and allow for much faster execution.
Well it depends on your model, but usually you need to do something like:
var model = from p in Product.Products.Include("SomeNavProperty")
.... (rest of query)
Where SomeNavProperty is the entity type that loads pTFi_fixedRate.
Hope that someone out there can help with this!
I'll give an example based on the standard Order-->OrderLine-->Product rather than the actual situation to make it easier to explain!
Basically, I want to run a query that returns all orders for which there is an order line containing a TV. Simple enough:
IEnumerable<Order> orders;
using (var context = new DataContext())
{
var source =
context.Orders.Include("OrderLines").Include(
"OrderLines.Product");
orders= source.Where(o => o.OrderLines.Where(ol => ol.Product.Name == "TV")).ToList();
}
return orders;
This works in the sense that I get the correct collection of Order entities, but when I use look at each Order's collection of OrderLines it contains all OrderLines not just those containing at TV.
Hope that makes sense.
Thanks in advance for any help.
I does make sense in that the query is fulfilling your original criteria "to return all orders for which there is an order line containing a TV", each order will of course have all the orderlines. The filter is only being used to select the Orders, not the OrderLines.
To retrieve just the OrderLines containing TV from an Order you'd use the filter again, thus:
var OrderLinesWithTV = order.OrderLines.Where(ol => ol.Product.Name == "TV");
The main point is to know if you need to keep (or not) a reference to the order header in the filtered lines.
I.e. do you want the list of all the orders with a TV, and more precisely only their TV lines ? or do you want all the TV lines nevermind their order header ?
You seem to prefer the first option.
Then the best solution would certainly be
var relevantOrders = orders.Where(order => order.OrderLines.Any(ol => ol.Product.Name == "TV"))
to get the relevant orders, and then, for each order in relevantOrders :
order.OrderLines.Where(ol => ol.Product.Name == "TV")
to consider only the TV lines.
Other techniques would result in a loss of information or force you to build a new orders collection similar to the initial one but double-filtered on the headers and on the lines, which seems fairly bad as far as elegance and performance is concerned.
Ok this should be really simple, but I am doing my head in here and have read all the articles on this and tried a variety of things, but no luck.
I have 3 tables in a classic many-to-many setup.
ITEMS
ItemID
Description
ITEMFEATURES
ItemID
FeatureID
FEATURES
FeatureID
Description
Now I have a search interface where you can select any number of Features (checkboxes).
I get them all nicely as an int[] called SearchFeatures.
I simply want to find the Items which have the Features that are contained in the SearchFeatures.
E.g. something like:
return db.Items.Where(x => SearchFeatures.Contains(x.ItemFeatures.AllFeatures().FeatureID))
Inside my Items partial class I have added a custom method Features() which simply returns all Features for that Item, but I still can't seem to integrate that in any usable way into the main LINQ query.
Grr, it's gotta be simple, such a 1 second task in SQL. Many thanks.
The following query will return the list of items based on the list of searchFeatures:
from itemFeature in db.ItemFeatures
where searchFeatures.Contains(itemFeature.FeatureID)
select itemFeature.Item;
The trick here is to start with the ItemFeatures table.
It is possible to search items that have ALL features, as you asked in the comments. The trick here is to dynamically build up the query. See here:
var itemFeatures = db.ItemFeatures;
foreach (var temp in searchFeatures)
{
// You will need this extra variable. This is C# magic ;-).
var searchFeature = temp;
// Wrap the collection with a filter
itemFeatures =
from itemFeature in itemFeatures
where itemFeature.FeatureID == searchFeature
select itemFeature;
}
var items =
from itemFeature in itemFeatures
select itemFeature.Item;