linq

LinqToXml vs LinqToSql...

Trying to "thaw" serialized objects that have been stored in an XML file: In LinqToSQL, I can (with a suitably decorated class) do this type of thing: [Table(Name="Plants")] public class Plant { [Column(Name = "Id", IsPrimaryKey = true)] public int Id { get; set; } [Column(Name = "Genus")] public string...

Enumerable.Cast<T> extension method fails to cast from int to long, why ?

Possible Duplicate: Puzzling Enumerable.Cast InvalidCastException Hi, I just noticed something quite strange with the Enumerable.Cast<T> extension method... It seems that it can't cast from int to long, even though this cast is perfectly legal. The following code fails with an InvalidCastException : foreach (var item ...

Linq query from 3 tables using Joiner table

I have 3 tables, Customer, Surfboards, and CustomerSurfboards. CustomerSurfboards is the Joiner table. Customer CustomerSurfBoards Surfboards ---------- ------------------- ------------ CustomerID CustomerSurfboardID SurfBoardID IsActive CustomerID SurfboardID I want to select all surfboards ...

Equalize data dictionary

Dictionary<DateTime, int> data1 Dictionary<DateTime, int> data2 not sorted if the dates in data1 is from **1/1/2000 - 1/1/2009** and the dates in data2 is from **1/1/2001 - 1/1/2007** then both Dictionaries<> should have the date ranging from **1/1/2001 - 1/1/2007** it could be the other way around. bascailly i need to remove the...

Key comparisons for Linq GroupBy using Default EqualityComparer

I'm trying to do a Linq GroupBy on some objects using an explicit key type. I'm not passing an IEqualityComparer to the GroupBy, so according to the docs: The default equality comparer Default is used to compare keys. It explains the EqualityComparer<T>.Default property like this: The Default property checks whether type T i...

linq to xml select

hi i have an xml like this <?xml version="1.0"?> <DataSetExchangeWMS xmlns="http://tempuri.org/DataSetExchangeWMS.xsd"&gt; <dtObjektInfo> <LanguageCode>1031</LanguageCode> <LiegenschaftID>7463</LiegenschaftID> </dtObjektInfo> 1040 7463 09 Now as i learned from tutorial i get my xml file and select nod...

Encoding in linq/entity framework

I'm working on a legacy where some fields uses special encodings. Is it somehow possible to set an decode the fields in the linq instead of doing as I'm doing now: XisoEncoding enc = new XisoEncoding() var q = from b in ent.Basket where b.ID == 22038 select b; Basket basket = query.First(); basket.STOMAN_MESSAG...

How to populate IEnumerable in Lambda expression?

I just cannot get this to work, would appreciate if someone can help. So I get back an XML result from a database which looks like: <matches> <issuer client_name="MTR" score="6" match_list="MTR CORPORATION LIMITED"/> <issuer client_name="PEOPLE''S REPUBLIC OF CHINA" score="4" match_list="DEMOCRATIC PEOPLE'S REPUBLIC OF KO...

Linq to SQL With Left Outer Join and Group By With Sum - How To

Hi ! I'm trying to transform the SQL Query below into Linq to SQL select Categorias.IdCategoria, Categorias.Nome, SUM(lancamentos.valor) from lancamentos left outer join Categorias on Lancamentos.IdCategoria = Categorias.IdCategoria where Month(DataLancamento) = 11 and Credito = 1 and Lancamentos.Ocultar = 0 group by Categorias...

Linq expression to filter formcollection

I have a FormCollection and I just want to only iterate through the keys the do not contain the string pricing. So what I tried was this... foreach (var key in collection.AllKeys.Where(k => !k.Contains("Pricing"))){ ... } The problem is the return is not a filtered list its returning boolean values... in which in need the filtered li...

Db4o query: find all objects with ID = {anything in array}

I've stored 30,000 SimpleObjects in my database: class SimpleObject { public int Id { get; set; } } I want to run a query on DB4O that finds all SimpleObjects with any of the specified IDs: public IEnumerable<SimpleObject> GetMatches(int[] matchingIds) { // OH NOOOOOOES! This activates all 30,000 SimpleObjects. TOO SLOW! ...

C# - code against a property using the property name as a string

What's the simplest way to code against a property in C# when I have the property name as a string? For example, I want to allow the user to order some search results by a property of their choice (using LINQ). They will choose the "order by" property in the UI - as a string value of course. Is there a way to use that string directly ...

NHibernate.Linq LIKE

How can I produce this query using NHibernate.Linq? WHERE this_.Name LIKE @p0; @p0 = 'test' // Notice NO % wild card Note, this is not Linq To Sql or Entity Framework. This is NHibernate. Edit: Here is the desired query using ICriteria: criteria.Add(Expression.Like("Name", "test")); return criteria.List<Theater>(); ...

How to write linq to get data from different tables?

Suppose I have 3 tables: A(aid, ...), B(bid, ...) Relationship(aid, bid, ...) Then I have a aid as parameter, I want to get the result from b. If use SQL, will be like select b.* from B join Relationship on b.bid = Relationship.bid where relationship.aid = aid_param how to write linq with same result as above SQL. (the foreign key was...

Using linq how do i remove multiple records from a cross reference table

Hi, My Database contains 4 tables: TABLE TBLCARTITEM (CART_ID, ITEM_ID, PROMOTION_ID, many more cart item fields) TABLE XREFCARTITEMPROMOTION (CART_ID, ITEM_ID, PROMOTION_ID) TABLE TBLPROMOTION (PROMOTION_ID, PROMOTION_TYPE_ID, many more promotion fields) TABLE TBLITEM (ITEM_ID, many more item fields) The XREFCARTIEMPROMOTION table ...

how does linq2sql keep track of database objects?

Hi, When using Linq2sql everything automagically works. My experience is that going with the flow is not always the best solution and to understand how something internally works is better so you use the technique optimally. So, my question is about linq2sql. If I do a query and get some database objects, or I create a new one, someho...

what is the easiest way to have multiple db connections when using linq

Optimally I would like linq to use X database connections instead of 1 to speed things up. The only way now is to open X connections, and create X databasecontexts, and associate them. It would be easier if somehow I could tell linq to use X connections. Is this possible? Or is there another way to speed up database queries? thanks e...

Basic LINQ syntax

Lets say you have an XML like like this: <data> <messages> <message name="Person" id="P"> <field name="FirstName" required="Y" /> <field name="LastName" required="Y" /> <field name="Sex" required="N" /> </message> <message name="Car" id="C"> <field name="Make" required="Y" /> <field name="Model" required=...

What was the name of the parallel implementation of Linq (not from Microsoft)

I remember seeing a link about it here where some people claimed it's 1000 times faster than the BCL Linq. Anyone used it here? Is it true? Also is Microsoft's PLinq gonna be along the same lines? Because it seemed to me like the above mentioned Linq was automatically parallel or something. And if that's the case, why isn't Microsoft ...

Rewriting this code cleaner using LINQ?

Here is a simplified version of the code I use: class Program { // Here is the ugly stuff static void DoStuff(int[] uidArray) { int chunkCount = (int)Math.Ceiling(uidArray.Length / 10d); for (int i = 0; i < chunkCount; i++) { // calculating the remaining uids. // this is super...