linq

C# Abstract Generic Method

C#, .net 3.5 I am trying to create a base class that has a generic method. Classes that inherit from it should specify the method's type(s). The premise for this is for creating classes that manage filtering. So I have: public abstract class FilterBase { //NEED Help Declaring the Generic method for GetFilter //public abstrac...

How can I split an IEnumerable<String> into groups of IEnumerable<string>

I have an IEnumerable<string> which I would like to split into groups of three so if my input had 6 items i would get a IEnumerable<IEnumerable<string>> returned with two items each of which would contain an IEnumerable<string> which my string contents in it. I am looking for how to do this with Linq rather than a simple for loop Thank...

Linq or Stored proc - Which should I choose?

An Activity occurs at a location on a specific date, but each activity may be repeated at the same or different locations on different dates. I have created an entity framework model, and wish to populate it with relevant Activities which occur between two dates, ordered by the locations distance from a specified location. I therefore ...

Can someone abuse LINQ and solve this money problem?

For the fun of it, I would like to see someone use and abuse LINQ to solve this money problem. I really have no idea how you would do it - I suppose Populating some set and then selecting off of it. If given a total number of coins and give the total amount of all coins added together: Show every possible combination of coins. Coins are...

How to write the following in Linq or Sql

Hi, Appreciate if I can get some help writing a LINQ that will get ALL FIELDS from table A, and those fields for which profile 1 has a value in table AB, show the value, otherwise if profile 1 has no entry in table AB, then show value as null. Table A AID Field ----------- 1 OneField 2 TwoField 3 ThreeField Table ...

LINQ to Entities: Why can't I use Split method as condition?

Hi, I have the following LINQ query: var aKeyword = "ACT"; var results = from a in db.Activities where a.Keywords.Split(',').Contains(aKeyword) == true select a; Keywords is a comma delimited field. Everytime I run this query I get the following error: "LINQ to Entities does not recognize the method 'Boo...

Building Linq Expressions with Variables

I am using Linq and the Entity Framework. I have a Page Entity, that has a many-to-many relationship to a Tag Entity. I want to create a Linq query that pulls all pages that match all of the supplied Tags (in the form of a Int64[]). I have tried various WhereIn, and BuildContainsExpression examples, but none are working as expected. ...

Use ID column of DataGridView as source of query of another DataGridView

I use LINQ to query my MSSQL 2005 database. I want to show several fields of some tables in one DataGridView. The selection of a row of the DataGridView should result in showing results in another DataGridView based on a column which is not shown in any DataGridView (it is an ID attribute). What is a good way to accomplish this? My I...

convert an sql query to Entity Framework

following sql query is working and gets the visits per day for the current month select date(date) as DayDate, count(*) As visitsaday from Visits group by DayDate having DayDate between date('now','start of month') and date('now','start of month','+1 month','-1 day') For days I try to figure out how to get this running with the entit...

Linq Select * from Table ExecuteQuery

First let me start by saying that I don't have a complete understanding of Linq. I am trying to dynamically query a database, The first query uses LINQ-SQL which works fine, but the second dynamic call is what fails in run time public void getTables() { foreach (var c in dc.GetTable<TableListing>()) { Li...

LINQ to Entities does not recognize the method 'Boolean Contains[Decimal]

Hi, I am new to LINQ, so I am pretty confused here. I have a database and try to run following code. IQueryable<decimal> location_ids = (from m in _db.Admins where m.UserId.Equals("c5d3dc0e-81e6-4d6b-a9c3-faa802e10b7d") select m.LocationId); if (!location_ids.Contai...

Load foreign key value with linq to entities

Hi, I have a table Admins, which creates a relationship between Users and Locations: ID - numeric (PK) UserId - uniqueidentifier (FK to UserId in aspnet_Users table) LocationId - numeric Now I want to execute command: IQueryable<decimal> location_ids = (from m in _db.Admins where m.UserId.Equals( n...

How to write linq query to match SQL like select top 100 * from tab?

WIth Ria Service, I have a linq query like: EntityQuery<Employee> query = from e in ctx.GetEmployeeQuery() orderby e.DateCreated descending select e; Then I want to get the top 100 records from this query, like SQL select top 100 * from Employee How to write the linq query? ...

Date function problem in SQL and Linq

I issued a SQL on SQL Server 2000: select * from Employee where LastUpdateDate >=DateAdd(yyyy,-1,Getdate()) It works fine and got some records. Then I write a Linq for the same purpose: EntityQuery<Employee> query = from e in ctx.GetEmployeeQuery() where e.DateCreated >= DateTime.Today.AddYears(-1) b...

Linq to Entities simple group query

How to write (simple) LINQ to Entities query that groups elements by some attribut and count them? SELECT answernumber, count(answerID) FROM answers WHERE questionID = id GROUB BY answernumber ORDERBY answernumber; That should be simple but i don't know how to write it. ...

Why Linq can't translate expression/treat as local expression and throws an exception?

I asked a question here about an Linq error that results from mixing Linq-To-SQL with C# code. In brief, the compiler gets confused and doesn't realize that you are intending to call a local function on the resultset after it's come back from the database. The answer I accepted was to use AsEnumerable() on the result set, thus forcing ...

Can't get a collection in a entity class

Suppose I have following tables with the right relationships built: Employee(empID, ...) Address(AddresID, ...) EmployeeAddress(EmpID, AddressID, ...) Then modified the generated code for GetEmployee by .NET RIA Services like: public IQueryable<Employee> GetEmployee() { var Employee = this.Context.Employee.Include("Employ...

get average Datetime from DB and subtract one Date from another

How to get an average time from an Datetime field via the Entity Framework ? How to subtract one Date from another ? I am thinking of something like: ObjectQuery<Visit> visits = myentitys.Visits; var uQuery = from visit in visits group visit by visit.ArrivalTime.Value.Day into g select ...

What is the best way to merge two objects during runtime using C#?

I have two objects and I want to merge them: public class Foo { public string Name { get; set; } } public class Bar { public Guid Id { get; set; } public string Property1 { get; set; } public string Property2 { get; set; } public string Property3 { get; set; } public string Property4 { get; set; } } To create:...

The Fruit Basket, how to use Linq to view from the basket or the fruit's perspective?

The question is related to financial products, interest rates and two properties that determine which interest a certain product has. But I think fruits and baskets are easier to visualize for this. First, we have fruit. Fruit can have a specific size (Small, medium, Large) and colour (Red, Green, Blue). These will be two different enum...