Converting IGrouping<T,U> to IGrouping<T,V> using LINQ
How can I do this conversion? Is it possible with some simple LINQ query? ...
linq
LINQ: display results from empty lists
I've created two entities (simplified) in C#: class Log { entries = new List<Entry>(); DateTime Date { get; set; } IList<Entry> entries { get; set; } } class Entry { DateTime ClockIn { get; set; } DateTime ClockOut { get; set; } } I am using the following code to initialize the objects: Log log1 ...
linq distinct field
how set distinct to this query return _dataContext.ProjectPictures.Include("Projects").Include("ProjectPictureTypes").Where(p => p.ProjectPictureTypes.Id == 1).ToList(); i need something like return _dataContext.ProjectPictures.Include("Projects").Include("ProjectPictureTypes").Where(p => p.ProjectPictureTypes.Id == 1).Distinct(p=>p...
Grafting LINQ onto C# 2 library
I'm writing a data access layer. It will have C# 2 and C# 3 clients, so I'm compiling against the 2.0 framework. Although encouraging the use of stored procedures, I'm still trying to provide a fairly complete ability to perform ad-hoc queries. I have this working fairly well, already. For the convenience of C# 3 clients, I'm trying ...
Code to apply expression tree directly to List
Is there a method call in Linq that will apply a expression tree directly on a List<V>? For instance, if I have a expression tree that is built on Order type, and i have a collection of List<Order> items on which i need to apply this expression. I am looking something similar to: class OrderListStore : IQueryable<V>, <other interfa...
Returning IQueryable or Enumerated Object
Hello everyone, I was wondering about the performance difference between these two scenarios and what could the disadvantages be over each other? First scenario : public class Helper //returns IQueryable { public IQueryable<Customer> CurrentCustomer { get{return new DataContext().Where(t=>t.CustomerId == 1); } } public...
Upper extension method in linq to NHibernate
I would like to use the Upper extension method which is declared on the IDbMethods interface against Sql Server 2008. The extension methods are defined in NHibernate.Linq.SqlClient.SqlClientExtensions I understand that this will translate to UPPER() on sql server. However I can not figure out how to get an implementation of IDbMethods...
IEnumerable<string> => unique string[]
Hello, I have a collection of IEnumerable<sentence> (sentence = string) I want to split all sentences to words (ex: .Select(t => t.Split(' ')), and after this I need to group this query by words to get a list of unique words. Please, Help ...
LINQ to XML query attributes
Hi using LINQ to XML, this is a sample of my XML <shows> <Show Code="456" Name="My Event Name"> <Event Code="2453" VenueCode="39" Date="2010-04-13 10:30:00" /> <Event Code="2454" VenueCode="39" Date="2010-04-13 13:30:00" /> <Event Code="2455" VenueCode="39" Date="2010-04-14 10:30:00" /> <Event Code="2456" VenueCode="39...
How can I join conditionally in LINQ queries?
If I have two tables; Drivers keyed by DriverId and Trips with foreign keys DriverId and CoDriverId, and I want to find all trips where a driver was either the driver or co-driver I could code this in Transact-SQL as select d.DriverId, t.TripId from Trips t inner join Drivers d on t.DriverId = d.DriverId or t.CoDriverId = d.DriverId ...
[C#]How to introduce retry logic into LINQ to SQL to deal with timeouts?
I need to find ways to add retry mechanism to my DB calls in case of timeouts, LINQ to SQL is used to call some sprocs in my code... using (MyDataContext dc = new MyDataContext()) { int result = -1; //denote failure int count = 0; while ((result < 0) && (count < MAX_RETRIES)) { result = dc.myStoredProc1(...); ...
LINQ and Storedprocedure
The interview i faced was "What is the difference between LINQ and Stored procedure?". I don't know whether it is a vague question or proper one. I answered "In Linq there is a support for Closure so you can refer the value of outer parameter inside the anonymous body,you can't do the same with Stored procedure". Just i am requesting ...
Fluent Nhibernate expression to select on flagged enum
I have a domain entity that has a flagged enum as a property. The flagged enum is the target audience for the these entities. The user then has a flagged enum value of the entities they should see. I am trying to figure out the correct expression to select entities that meet the target audience for the user. public class File { pu...
Error: FormatException was unhandled by user code in Linq how to solve?
Look please below this codes throw me : FormatException was unhandled by user code Codes: satis.KDV = Decimal.Parse((from o in genSatisctx.Urun where o.ID == UrunID select o.Kdv).ToString()); How can i rewrite linq query? ...
Using LINQ, how do you get all label controls.
I want to get a collection of all label controls that are part of a user control. I have the following code: var labelControls = from Control ctl in this.Controls where ctl.GetType() == typeof(Label) select ctl; but the result is zero results. Please assist. Thanks. Ed...
Trying to generate all sequences of specified numbers up to a max sum
Hi, Given the following list of descending unique numbers (3,2,1) I wish to generate all the sequences consisting of those numbers up to a maximum sum. Let's say that the sum should be below 10. Then the sequences I'm after are: 3 3 3 3 3 2 1 3 3 2 3 3 1 1 1 3 3 1 1 3 3 1 3 3 3 2 2 2 3 2 2 1 1 3 2 2 1 3 2 2 3 2 1 1 1 1 3 2 1 1 1 3 2 1...
Reading XML using XDocument & Linq - check if element is NULL?
I'm using LINQ together with XDocument to read a XML File. This is the code: XDocument xml = XDocument.Load(filename); var q = from b in xml.Descendants("product") select new { name = b.Element("name").Value, price = b.Element("price").Value, extra = b.Element("ext...
LINQ: transform an array [,] into array[]
I know this is kind of a dumb question, but does anyone have an elegant (or non-elegant) LINQ approach to transform a 2D array (object[,]) into a 1D array (object[]) comprised of the first dimension of the 2D array? Example: // I'd like to have the following array object[,] dim2 = {{1,1},{2,2},{3,3}}; // conv...
Linq collection with a collection and pivot
Hi, I'm trying to convert the following structure: Name Metadata Metadata Name Metadata Metadata with data such as Fred Surname, Bill Dob, 20/01/2009 Mike Surname, Jones Dob, 10/09/2000 into a collection of an anonymous class with the following properties: Name, Surname, Dob I'm trying to do it through Linq an...
How to get items that are and are not in a list
I have an IEnumerable, listOfOnes, and an IEnumerable, listOfTwos. Assuming that I can compare objects of V against objects of T, I'd like to find which items are in listOfOnes but, not in listOfTwos. And vice versa. ex: var listOfOnes = new List<One> { new One { name = "chris", ...