linq

Group XDocument.Descandants

How to group xml element values XDocument.Descandants("Customer").GroupBy(c=>c.Element("ServiceId")); This is not working. Is there any way to group this? ...

Using LINQ to Update A Property in a List of Entities

Say I have an entity that looks something like this simple example: MyEntity { int property1; int property2; int property3; } Now assume I have an IEnumerable list of these entites. Is there a LINQ query I can execute that would set the value of property1 to 100 for each entity in the list? I know I can do this via a foreach,...

Determine is XElement contains valid xml

Hi, I have an application that makes hundreds of calls to a third party web service. Each time a call is made the response is parsed into XElement and a series of operations are performed on it. The processed XElement is then added to an XDocument that is later saved to disk. Occasionally a response will include some bad data. In this...

problem with linq (C#)

var pom= from k in dataContext.student_gods where k.skgod==System.Convert.ToString(2002/03) select k; foreach(var i in pom){ var predmeti = from m in dataContext.student1s where m.id_stud ==System.Convert.ToString(i.id_stud) ...

LINQ: query to sum on grouped field

I've a list of tasks. Ie I've struct like struct Task { public DateTime Completed { get; set; } public string TaskKind { get; set; } public float Effort { get; set; } } And I've a IList<Task>. Now I want to group the tasks based on the date and group by TaskKind on each day with the summed effort. For eg for I want to pri...

Unexplained Linq select behaviour

Ok, this is very weird. I'm using SubSonic 3.0 and Linq to select a list of IDs (and other properties) into a list of user-defined-objects. Like this: public class ListItem { public int C { get; set; } } public class ListItemWithID { public int ID { get; set; } ...

How to take all but the last element in a sequence using LINQ?

Hi everyone, Let's say I have a sequence. IEnumerable<int> sequence = GetSequenceFromExpensiveSource(); // sequence now contains: 0,1,2,3,...,999999,1000000 Getting the sequence is not cheap and is dynamically generated, and I want to iterate through it once only. I want to get 0 - 999999 (i.e. everything but the last element) I rec...

Does Linq Remove The Need For Hibernate?

Just wondering whether anyone will still use Hibernate once they move to C# 3 Are these mutually exclusive?? ...

How to check for an empty set in Linq to NHibernate query

I have the following nhibernate mapping <class name="Customer"> <id name="Id"> <generator class="native"/> </id> <property name="Name"/> <set name="Invoices" cascade="all" lazy="false"> <key column="CustomerId"/> <one-to-many class="Invoice"/> </set> </class> <class name="Invoice"> <id name="Id"> <generator ...

problem with conversion

This code doesn't return data from table: var pom = from k in dataContext.student_gods where k.skgod == System.Convert.ToString(2002/03) select k.id_stud; This code does return data from table: var pom = from k in dataContext.student_gods where k.skgod== "2002/03" ...

Converting Linq to XML result to generic list in VB.Net. Odd error.

I have a function that works great in C# that I'm converting to VB.Net. I'm having an issue converting the result set to a generic list in VB.net. The code: Public Function GetCategories() As List(Of Category) Dim xmlDoc As XDocument = XDocument.Load("http://my_xml_api_url.com") Dim categories = (From category In xmlDoc.Descendan...

Dynamic variables in linq select statement

I have a listbox that is dynamically filled by certain values depending on what table has been selected from another list box. Once a value is selected, it is being graphed vs a date & time range. With my ignorance of linq: depending on what value is selected, the linq to sql statement I need to create to grab data from my database is di...

Generate a two dimensional array via LINQ

I am trying to create a matrix of doubles, representing a correlation between entities. Here's how I'm doing it via LINQ double[][] correlationsRaw = (from e in entitiesInOrder select (from f in entitiesInOrder select correlations.GetCorr...

How can I send where statements to a method which are dynamically executed in a LINQ statement?

In the following example, GetFilteredCustomers() works fine so I can send various letters which I want customers to have in their last name. But how can I build GetFilteredCustomersDynamic() which will enable me to send a full where clause that can be dynamically included in the LINQ statement? using System; using System.Collections.Ge...

Help converting foreach to Linq

Hi all, this is a homework question. I am doing diffs on our domain model and I've set it up so that I can iterate a list of operations that check for certian differences within the domain. I pass in the differencing function and the before and after states of the object graph to produce a result in the DiffContext - which is used late...

LINQ to SQL Custom Property query on where clause

I am using LINQ to SQL classes, and have extended one (with a partial class) and added an extra property. I want to query on this property, so: (from p in db.TableName where p.CustomProperty=="value" select p) However this doesn't work. I get an error: The member 'TableName.CustomProperty' has no supported translation to SQL. At the...

How to process multiple where clauses in a LINQ statement?

Thanks to those who answered my last question I got the code below to work which allows the developer to send multiple where clauses to a method which includes each of them in a LINQ statement. However, how can I get the inclusion of the where clauses to be dynamic? Instead of this: return customers .Where(whereClauses[0]) ...

Windows Forms Click event repeating itself

I have a strange problem with a Windows Forms event. To be exact, it's a KryptonHeaderGroup's ButtonSpec Click event, but it also happens with a plain vanilla System.Windows.Forms.Button. In the click event, the user interface is brought down (there's a label and a cancel button left), and then an expensive LINQ query is built from prev...

What is the best approach to build dynamic LINQ queries?

Thanks to those who answered my last couple questions, I got the following code to work which allows you to send a collection of Where clauses to a method which are all attached to a LINQ query. This is going to work for the case at hand that I need. However, what is the best approach to extend this so that: OrderBy clauses can be sen...

Can it be advantageous for a method to return IOrderedEnumerable<T> instead of IEnumerable<T>?

Can it be advantageous for a method to return IOrderedEnumerable instead of IEnumerable? ...