linq

Query To retrieve Desc. From Id In Linq

I m new in Linq and i didnt understang this query Db.Enum_Countries .Where(p=>p.id==id) .Single() .Title) Can you help me.... ...

Changing DBML, how to change SQL database?

Hi all, A have an app with that uses an SQL database. The application is already released, but now I'm working on an update. In the update I've added an extra column in a table of my database. I've create the database from my DMBL using DataContext.CreateDatabase() (not the other way around, as I found out to be the more common scenari...

Linq-To-Objects group by

Hey, I'm building a software for timereporting I have a Dictionary<string, Dictionary<string, double>>. The key in the main dictionary is a users name and their value is a dictionary of . I have a function GetDepartment(string UserName) which returns a string with the users department. What I want is to crate a new dictionary, of t...

Linq to SQL - Returning two values with one query

Hi, Is it possible to return a single value and an enumerable collection using LINQ to SQL? The problem is, I'm trying to do paging across a large recordset. I only want to return 10 rows at a time so I'm using .Skip(20).Take(10) approach. However I need to know the total number of records so I can show an appropriate page x of y. Tr...

Normalizing chains of .Skip() and .Take() calls

I'm trying to normalize arbitrary chains of .Skip() and .Take() calls to a single .Skip() call followed by an optional single .Take() call. Here are some examples of expected results, but I'm not sure if these are correct: .Skip(5) => .Skip(5) .Take(7) => .Skip(0).Take(7) .Skip(5).Skip(7) ...

Linq-to-SQL: Ignore null parameters from WHERE clause

The query below should return records that either have a matching Id supplied in ownerGroupIds or that match ownerUserId. However is ownerUserId is null, I want this part of the query to be ignored. public static int NumberUnderReview(int? ownerUserId, List<int> ownerGroupIds) { return ( from c in db.Contacts ...

c#: Clean way to fit a collection into a multidimensional array?

I have an ICollection<MapNode>. Each MapNode has a Position attribute, which is a Point. I want to sort these points first by Y value, then by X value, and put them in a multidimensional array (MapNode[,]). The collection would look something like this: (30, 20) (20, 20) (20, 30) (30, 10) (30, 30) (20, 10) And the final product: (20...

How can I query all Childcontrols of a Winform recursively?

Iam using windows forms. How can I query all child controls of a Form recursively which have a certain type? In SQL you would use a selfjoin to perform this. var result = from this join this ???? where ctrl is TextBox || ctrl is Checkbox select ctrl; Can I also do this in LINQ? EDIT: LINQ supports joins. Why can't I use...

Linq insert statement inserts nothing, does not fail either

I am trying to insert a new account in my Acccounts table with linq. I tried using the EntityModel and Linq2Sql. I get no insert into my database nor an exception of any kind. public static Linq2SQLDataContext dataContext { get { return new Linq2SQLDataContext(); } } try { //EntityModel Accounts acc = Accounts.C...

nhibernate activerecord linq Contains problem

Hi, I am having problems with the following query in Castle ActiveRecord 2.12: var q = from o in SodisceFMClientVAR.Queryable where taxnos2.Contains(o.TaxFileNo) select o; taxNos2 is an array of strings. When run I get an exception: + InnerException {"Index was out of range. Must be non-negative and ...

Linq to SQL problem

I have a local collection of record Id's (integers). I need to retrieve records that have every one of their child records' ids in that local collection. Here is my query: public List<int> OwnerIds { get; private set; } ... filteredPatches = from p in filteredPatches where OwnerIds.All(o => p.PatchesOwners.Select(x =...

Getting a set of elements using linq

I have the following piece of XML: <xml> <ObsCont xCampo="field1"> <xTexto>example1</xTexto> </ObsCont> <ObsCont xCampo="field2"> <xTexto>example2</xTexto> </ObsCont> <ObsCont xCampo="field3"> <xTexto>example3</xTexto> </ObsCont> </xml> How do I (using linq) get for example what is inside the xTexto...

How can I access the group of a linq group-by query from a nested repeater control?

I'm using a linq group by query (with two grouping parameters) and would like to use the resulting data in a nested repeater. var dateGroups = from row in data.AsEnumerable() group row by new { StartDate = row["StartDate"], EndDate = row["EndDate"] }; "data" is a DataTable from an SqlDataAdapter-filled DataSet. "dateGroups" is us...

LINQ - is SkipWhile broken?

I'm a bit surprised to find the results of the following code, where I simply want to remove all 3s from a sequence of ints: var sequence = new [] { 1, 1, 2, 3 }; var result = sequence.SkipWhile(i => i == 3); // Oh noes! Returns { 1, 1, 2, 3 } Why isn't 3 skipped? My next thought was, OK, the Except operator will do the trick: var s...

Add new node to xml tree

Hello, I am generating a xml tree: var root = new XElement("Root"); for(int i =0;i<3;i++) { var sub0lvl = new XElement(String.Format("sub{0}",i)); root.Add(sub0lvl); for(int j=0;j<2;j++) { sub0lvl.Add(new XElement(String.Format("subsub{0}",i))); } } This code generate follow xml tree: <Root> <sub0> <subsub...

C# -Closure -Clarification

I am learning C#.Can I mean closure as a construct that can adopt the changes in the environment in which it is defined. Example : List<Person> gurus = new List<Person>() { new Person{id=1,Name="Jon Skeet"}, new Person{id=2,Name="Marc Gravell"}, new Person{id=3,N...

Left Join in Subsonic 3

I'm trying to do a left join in subsonic 3 using linq but it doesn't seem to work, I get a big error. var post = from p in Post.All() join q in Quote.All() on p.ID equals q.PostID into pq where p.ID == id.Value from qt in pq.DefaultIfEmpty() select n...

Partial Evaluation of ConstantExpression in ExpressionTreeVisitor

Hi all, I am not an Expression Tree master by any stretch of the imagination, what I have is code that looks like this: int external = 10; using(var session = new Session()) { session.Add(new Product { Name = "test1", Price = 20 }); session.Add(new Product {Name = "test", Price = 10}); var product = sess...

How to choose programaticaly the column to be queried by Linq using PropertyInfo???

Hello, I would like to control how linq querries my database programaticaly. For instance, I'd like to query the column X, column Y, or column Z, depending on some conditions. First of all, I've created an array of all the properties inside my class called myPropertyInfo. Type MyType = (typeOf(MyClass)); PropertyInfo[] myPropertyInfo ...

How to write this Linq SQL as a Dynamic Query (using strings)?

Skip to the "specific question" as needed. Some background: The scenario: I have a set of products with a "drill down" filter (Query Object) populated with DDLs. Each progressive DDL selection will further limit the product list as well as what options are left for the DDLs. For example, selecting a hammer out of tools limits the Pr...