Search Results

Search found 57 results on 3 pages for 'selectmany'.

Page 2/3 | < Previous Page | 1 2 3  | Next Page >

  • help with exception handling in linq

    - by stackoverflowuser
    I have the following code to retrieve customer name, total (orders ), sum (order details) for reach customer in Northwind database. The problem with below code is that it raises an exception since a few customers dont have any entry in orders table. I know using the query syntax (join) the exception can be avoided. I want to know if the same can be handled with the extension method syntax. CustomerOrderDataContext db = new CustomerOrderDataContext(); var customerOrders = db.Customers.Select(c => new { CompanyName = c.CompanyName, TotalOrders = c.Orders.Count(), TotalQuantity = c.Orders.SelectMany(o => o.Order_Details).Sum(o=>o.Quantity) });

    Read the article

  • Hos to group the complex list objects by using Linq

    - by Daoming Yang
    I want to select and group the products, and rank them by the number of times they occur. For example, I have an OrderList each of order object has a OrderProductVariantList(OrderLineList), and each of OrderProductVariant object has ProductVariant, and then the ProductVariant object will have a Product object which contains product information. A friend helped me with the following code. It could be compiled, but it did not return any value/result. I used the watch window for the query and it gave me "The name 'query' does not exist in the current context". Can anyone help me? Many thanks. var query = orderList.SelectMany( o => o.OrderLineList ) // results in IEnumerable<OrderProductVariant> .Select( opv => opv.ProductVariant ) .Select( pv => p.Product ) .GroupBy( p => p ) .Select( g => new { Product = g.Key, Count = g.Count() });

    Read the article

  • Please help, now I have a matrix, I want use Combination algorithm to generate a array for length 6

    - by user313429
    The first thanks a lot for your help , the following is my matrix, I want to implement combination algorithm between multiple arrays in LINQ for this matrix. int[,] cj = { { 10, 23, 16, 20 }, { 22, 13, 1, 33 }, { 7, 19, 31, 12 }, { 30, 14, 21, 4 }, { 2, 29, 32, 6 }, { 18, 26, 17, 8 }, { 25, 11, 5, 28 }, { 24, 3, 15, 27 } }; other: public static IEnumerable<IEnumerable<T>> Combinations<T>(this IEnumerable<T> elements, int k) { return k == 0 ? new[] { new T[0] } : elements.SelectMany((e, i) => elements.Skip(i + 1).**Combinations**(k - 1).Select(c => (new[] { e }).Concat(c))); } The above method has a error in my project, System.Collections.Generic.IEnumerable' does not contain a definition for 'Combinations' and no extension method 'Combinations' accepting a first argument of type 'System.Collections.Generic.IEnumerable' could be found (are you missing a using directive or an assembly reference? I use .Net Framework3.5, what is the reason it?

    Read the article

  • Exception handling in Linq to SQL for customers without orders

    - by stackoverflowuser
    I have the following code to retrieve customer name, total (orders ), sum (order details) for reach customer in Northwind database. The problem with below code is that it raises an exception since a few customers dont have any entry in orders table. I know using the query syntax (join) the exception can be avoided. I want to know if the same can be handled with the extension method syntax. var customerOrders = db.Customers .Select(c => new { CompanyName = c.CompanyName, TotalOrders = c.Orders.Count(), TotalQuantity = c.Orders .SelectMany(o => o.Order_Details).Sum(o=>o.Quantity) });

    Read the article

  • How to pass content in response from Exception filter in Asp.net WebAPI?

    - by jaffa
    Consider following code: My problem is: 1) I can't seem to cast the errors to HttpContent 2) I can't use the CreateContent extension method as this doesn't exist on the context.Response.Content.CreateContent public class ServiceLayerExceptionFilter : ExceptionFilterAttribute { public override void OnException(HttpActionExecutedContext context) { if (context.Response == null) { var exception = context.Exception as ModelValidationException; if ( exception != null ) { var modelState = new ModelStateDictionary(); modelState.AddModelError(exception.Key, exception.Description); var errors = modelState.SelectMany(x => x.Value.Errors).Select(x => x.ErrorMessage); // Cannot cast errors to HttpContent?? // var resp = new HttpResponseMessage(HttpStatusCode.BadRequest) {Content = errors}; // throw new HttpResponseException(resp); // Cannot create response from extension method?? //context.Response.Content.CreateContent } else { context.Response = new HttpResponseMessage(context.Exception.ConvertToHttpStatus()); } } base.OnException(context); } }

    Read the article

  • Linq: How to calculate the sales Total price and group them by product

    - by Daoming Yang
    I have a order list and I want to generate and rank the product with its total sales and quantity. With @tvanfosson's help, I can bring the grouped product detail with the following code, but how can I calculate and add up the total sales and quantity into each productListResult's object? Can anyone help me with this? Many thanks. var orderProductVariantListResult = productList.SelectMany(o => o.OrderProductVariantList) .Select(opv => new { Product = opv.ProductVariant.Product, Quantity = opv.Quantity, PriceSales = opv.PriceSales, Sales = opv.Quantity * opv.PriceSales, }); var productListResult = orderProductVariantResult .Select(pv => pv.Product) .GroupBy(p => p) .Select(g => new { Product = g.Key, TotalOrderCount = g.Count() }) .OrderByDescending(x => x.TotalOrderCount).ToList();

    Read the article

  • AppDomain assemblies not being loaded correctly.

    - by SharePoint Newbie
    Hi, We are doing the following in the Application_Start (Global.ascx.cs) for a WCF Service hosted by IIS 7.0 (integrated pipeline). var mapperConfigurations = AppDomain.CurrentDomain.GetAssemblies() .SelectMany(a => a.GetExportedTypes().Where(t => typeof (IMapperConfiguration).IsAssignableFrom(t) && t.IsClass)) .ToList(); The web-service has 8-10 assemblies in its bin folder and each of them have multiple implementations of IMapperConfiguration. After an IIS Reset, no mapper configurations are found (found this using debug.write). However, this behaviour is inconsistent and at other times all implementations of IMapperConfiguration are found. When exactly does IIS load assemblies and what is wrong with this code? Thanks

    Read the article

  • linq2sql left join with "multiselect"

    - by just_azho
    Hi, folks I'm trying to achieve following by linq2sql, but not successful. I've Member and Reference tables. DB is design in such a manner that Member can have multiple (=0) References. What I want as a result of query is, list (rows) of members, where all references of the member are "collected" in one column. What I had achieved is following query, but for this one there exist a row for each Reference. var refs = (from m in db.Members join r in db.References on m.PID equals r.PID into g from o in g.DefaultIfEmpty() select new { member = m, name = (o == null ? "" : o.NameSurname) }); I feel I need to insert SelectMany somewher :) Could you please give hints on achieving the goal?

    Read the article

  • Deferred Shading - Toolkit

    - by AliveDevil
    I recently managed to get some lights rendered in a scene by using a buffer and a for-loop. The problem with this method is the performance drop if more lights are used. I tried to convert Deferred Rendering in XNA4.0 | ROY-T.NL but it is not working, because I am not using any models. I know I have to render color, normals and lights seperate but I don't know how I could get it working. For understanding my structure better I'm using a world-class which holds some chunks. These chunks are loading all vertices from their items. These items have a property which returns the vertices. The item is returning VertexPositionNormalTexture[]. The chunk loads these Vertices and combines them to one large array of VertexPositionNormalTexture via someList.AsParallel().SelectMany(m => m).ToArray()). m is a VertexPositionNormalTexture. someList is List<VertexPositionNormalTexture>. I got my own shader to draw these vertices how I want them to be drawn. The first thing I would try is setting up two RenderTarget2D for rendering the color and normal part. With two different shaders. Than I would have to render the lights and there's the problem: I don't know how. I set up a structure to simplify working with lights but it didn't really help. public struct Light { public Vector3 Position; public Color4 Color; public float Range; public float Intensity; public Light( Vector3 position, Color color, float range, float intensity ) : this() { this.Position = position; this.Color = color; this.Range = range; this.Intensity = intensity; } public float[] Definition { get { return new[] { Position.X, Position.Y, Position.Z, Color.Red, Color.Green, Color.Blue, Intensity, Range }; } } } The next part is equally different because I don't know how to combine the colorMap, normalMap and textureMap to one finalMap. Some information to the system: I'm using SharpDX (Nightly from some months ago) and the SharpDX.Toolkit (I don't want to mess up with Direct3DDevice and similar things). Can someone help me with this problem? If things are missing or I provided insufficient information tell me, I need to get deferred shading working. Things I'm not able to do: create a rendertarget which holds all lights, merge colorMap, normalMap and lightMap to one finalMap and presenting this to the user.

    Read the article

  • Silverlight Cream for March 09, 2011 -- #1057

    - by Dave Campbell
    In this Issue: Dennis Doomen, Peter Kuhn, Michael Crump, Joe McBride, Martin Krüger, Jeremy Likness, Manas Patnaik, Jesse Liberty(-2-), WindowsPhoneGeek(-2-). Above the Fold: Silverlight: "A highlighting AutoCompleteBox in Silverlight" Peter Kuhn WP7: "WP7 WatermarkedTextBox custom control" WindowsPhoneGeek Training: "" Shoutouts: Karl Shifflett announced that he and Josh Smith have heard the developers and released a demo: Mole 2010 Demo Released This is a somewhat older post, but the material is good and I was reminded of it while talking to Josh Smith at the MVP summit last week: Advanced MVVM ... money well-spent From SilverlightCream.com: Introducing the Silverlight Cookbook Dennis Doomen unveils a Codeplex site "containing a Silverlight 4 app that includes most of the complexities you might run into" ... I'm tagging this in my WynApse outlookbar... great stuff, Dennis! A highlighting AutoCompleteBox in Silverlight Peter Kuhn took on a task in response to a forum query and created a highlighting AutoCompleteBox, and is giving it to us... this really looks cool, Peter, and great explanation. Taking a look at the Mindscape Phone Elements for WP7. Michael Crump takes a good look at the Mindscape Phone Elements for WP7... and if you read closely you might still be able to get a free license! Windows Phone – “Can’t connect to your phone. Disconnect it, Restart it, then try connecting again.” Joe McBride explains a way out of an issue that many should be seeing as we repave or replace machines... how to get our device recognized on the updated machine... without giving cryptic messages. How to: only with the full visibility of an application in the browser window start an action Martin Krüger continues his journey in starting storyboards and tackles the condition that the application is completely in the browser window prior to the storyboard starting. A Numeric Input Control for Windows Phone 7 Jeremy Likness came up with a great idea for numeric input for WP7 ... you'll smile when you see it, but what a great idea... and a NumericTextBox to go along with it. Performing CRUD on Relational Data (Multiple table) using RIA in SL4 Manas Patnaik has a post up that breaks the normal blog post or demo mold by having two tables with a relational constraint and doing CRUD operations on them. Plenty of diagrams and good information. Select Many: Reactive Extensions’ Mother Of All Operators [Chaining] Jesse Liberty has part 9 in his Rx series up, and is looking at SelectMany this time, and chaining calls. He's using WPF for the sample, but the goodness is all there for us Silverlight guys too. The Full Stack 8–Adding Search to the Phone Client Jesse Liberty and Jon Galloway have part 8 of their Full Stack series up ... this is the MVC3, ASP.NET, Silverlight, and WP7 app development series... this time out they're putting Search in the Phone client. All about ResourceDictionary in WP7 WindowsPhoneGeek is discussing ResourceDictionaries in this post... beginning with What is a ResourceDictionary and continuing out through creating and using one, plus a good comment on merging. WP7 WatermarkedTextBox custom control In his next post, WindowsPhoneGeek walks us through the creation of a WatermarkedTextBox for WP7 right from the derivation from TextBox... very nice tutorial and lots of code/examples. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

    Read the article

  • Silverlight Cream for March 10, 2011 -- #1058

    - by Dave Campbell
    In this Issue: Ian T. Lackey, Peter Kuhn, WindowsPhoneGeek(-2-), Jesse Liberty(-2-), Martin Krüger, John Papa, Jeremy Likness, Karl Shifflett, and Colin Eberhardt. Above the Fold: Silverlight: "Silverlight TV 65: 3D Graphics" John Papa WP7: "Developing a Windows Phone 7 Jump List Control" Colin Eberhardt Shoutouts: Telerik announced a special sale on their RadControls for WP7... check it out: RadControls for Windows Phone 7 - on Sale from March 16th at a Special Promo Price! From SilverlightCream.com: Prism BootStrapper Load ModuleCatalog Ansyc Ian T. Lackey has a post up about reading the module catalog for Prism from an XML file asynchronously... fun stuff... this is how we kick-started our app... XNA for Silverlight developers: Part 6 - Input (accelerometer) Peter Kuhn has Part 6 of his XNA for Silverlight devs up at SilverlightShow. This post is on the use of the accelerometer... some great diagrams and explanations of it's use along with some code to play with... including a 'problems and pitfalls' section, and some good external links. Getting Started with Unit Testing in Silverlight for WP7 WindowsPhoneGeek has an introduction to Unit Testing in general, and then moves into Unit Testing in Silverlight for WP7, providing 3 options with links to the materials and code demonstrating the concepts. Using DockPanel in WP7 Responding to reader's questions, WindowsPhoneGeek's next post is on the DockPanel from the Silverlight Toolkit, and using it in WP7... defined declaratively and in code. Reactive Extensions–More About Chaining Jesse Liberty has post number 10 on Rx up and is a follow-on to the last one on Chaining. This time he exercises the chaining aspect of SelectMany. Yet Another Podcast #26–Walt Ritscher In his next post, Jesse Liberty has his 26th 'Yet Another Podcast' up and is chatting with my friend Walt Ritscher. If you don't know who Walt is, check out the links Jesse has on the post... I'm sure you've crossed paths. How to: Create A half square from a regular polygon (triangle) Martin Krüger demonstrates the exact placement of a half-square (isosceles right triangle), formed with a regular polygon in Blend... this is much more involved than I've made it sound... check out his post. Silverlight TV 65: 3D Graphics John Papa has Silverlight TV number 65 up and it's all about the 3D graphics stuff we saw at the Firestarter. John is talking with Danny Riddel, the CEO of Archetype, the company that built the awesome 3D demo we all gushed over. Jounce Part 12: Providing History-Based Back Navigation Jeremy Likness has part 12 of his Jounce exploration up... and discussing the stack of navigated pages that Jounce retains and providing a 'go back' functionality... and provides a good example of using it all. Prism 4 Region Navigation with Silverlight Frame Navigation and Unity Karl Shifflett has a post for all us Prism afficianados... Prism, Unity, and the Silverlight Frame Navigation framework. Some great external links for 'required reading' too. Developing a Windows Phone 7 Jump List Control Colin Eberhardt has an awesome tutorial up for creating a JumpList control for WP7... what a bunch of effort... this is a step-by-step description of designing the control he built and blogged about a while back... and it's still cool! Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

    Read the article

  • EF4 querying from parent to grandchildren

    - by Hans Kesting
    I have a model withs Parents, Children and Grandchildren, in a many-to-many relationship. Using this article I created POCO classes that work fine, except for one thing I can't yet figure out. When I query the Parents or Children directly using LINQ, the SQL reflects the LINQ query (a .Count() executes a COUNT in the database and so on) - fine. The Parent class has a Children property, to access it's children. But (and now for the problem) this doesn't expose an IQueryable interface but an ICollection. So when I access the Children property on a particular parent all the Parent's Children are read. Even worse, when I access the Grandchildren (theParent.Children.SelectMany(child => child.GrandChildren).Count()) then for each and every child a separate request is issued to select all data of it's grandchildren. That's a lot of separate queries! Changing the type of the Children property from ICollection to IQueryable doesn't solve this. Apart from missing methods I need, like Add() and Remove(), EF just doesn't recognize the navigation property then. Are there correct ways (as in: low database interaction) of querying through children (and what are they)? Or is this just not possible?

    Read the article

  • Linq to XML: create an anonymous object with element attributes and values

    - by Phil Scholtes
    I'm new to Linq and I'm trying to query a XML document to find a list of account managers for a particular user. (I realize it might make more sense to put this in a database or something else, but this scenario calls for a XML document). <user emailAddress='[email protected]'> <accountManager department='Customer Service' title='Manager'>[email protected]</accountManager> <accountManager department='Sales' title='Account Manager'>[email protected]</accountManager> <accountManager department='Sales' title='Account Manager'>[email protected]</accountManager> </user> I trying to create a list of objects (anonymous type?) with properties consisting of both XElement attributes (department, title) and values (email). I know that I can get either of the two, but my problem is selecting both. Here is what I'm trying: var managers = _xDoc.Root.Descendants("user") .Where(d => d.Attribute("emailAddress").Value == "[email protected]") .SelectMany(u => u.Descendants("accountManager").Select(a => a.Value)); foreach (var manager in managers) { //do stuff } I can get at a.Value and a.Attribute but I can't figure out how to get both and store them in an object. I have a feeling it would wind up looking something like: select new { department = u.Attribute("department").Value, title = u.Attribute("title").Value, email = u.Value };

    Read the article

  • Is it possible to implement an infinite IEnumerable without using yield with only C# code?

    - by sinelaw
    Edit: Apparently off topic...moving to Programmers.StackExchange.com. This isn't a practical problem, it's more of a riddle. Problem I'm curious to know if there's a way to implement something equivalent to the following, but without using yield: IEnumerable<T> Infinite<T>() { while (true) { yield return default(T); } } Rules You can't use the yield keyword Use only C# itself directly - no IL code, no constructing dynamic assemblies etc. You can only use the basic .NET lib (only mscorlib.dll, System.Core.dll? not sure what else to include). However if you find a solution with some of the other .NET assemblies (WPF?!), I'm also interested. Don't implement IEnumerable or IEnumerator. Notes The closest I've come yet: IEnumerable<int> infinite = null; infinite = new int[1].SelectMany(x => new int[1].Concat(infinite)); This is "correct" but hits a StackOverflowException after 14399 iterations through the enumerable (not quite infinite). I'm thinking there might be no way to do this due to the CLR's lack of tail recursion optimization. A proof would be nice :)

    Read the article

  • If I select from an IQueryable then the Include is lost

    - by Connor Murphy
    The include does not work after I perform a select on the IQueryable query. Is there a way arround this? My query is public IQueryable<Network> GetAllNetworks() { var query = (from n in _db.NetworkSet .Include("NetworkContacts.Contact") .Include("NetworkContacts.Contact.RelationshipSource.Target") .Include("NetworkContacts.Contact.RelationshipSource.Source") select (n)); return query;; } I then try to populate mya ViewModel in my WebUI layer using the following code var projectedNetworks = from n in GetAllNetworks() select new NetworkViewModel { Name = n.Name, Contacts = from contact in networkList .SelectMany(nc => nc.NetworkContacts) .Where(nc => nc.Member == true) .Where(nc => nc.NetworkId == n.ID) .Select(c => c.Contact) select contact, }; return projectedNetworks; The problem now occurs in my newly createdNetworkViewModel The Contacts object does include any loaded data for RelationshipSource.Target or RelationshipSource.Source The data should is there when run from the original Repository IQueryable object. However the related include data does not seem to get transferred into the new Contacts collection that is created from this IQueryable using the Select New {} code above. Is there a way to preserve this Include data when it gets passed into a new object?

    Read the article

  • C# reflection instantiation

    - by NickLarsen
    I am currently trying to create a generic instance factory for which takes an interface as the generic parameter (enforced in the constructor) and then lets you get instantiated objects which implement that interface from all types in all loaded assemblies. The current implementation is as follows:     public class InstantiationFactory     {         protected Type Type { get; set; }         public InstantiationFactory()         {             this.Type = typeof(T);             if (!this.Type.IsInterface)             {                 // is there a more descriptive exception to throw?                 throw new ArgumentException(/* Crafty message */);             }         }         public IEnumerable GetLoadedTypes()         {             // this line of code found in other stack overflow questions             var types = AppDomain.CurrentDomain.GetAssemblies()                 .SelectMany(a = a.GetTypes())                 .Where(/* lambda to identify instantiable types which implement this interface */);             return types;         }         public IEnumerable GetImplementations(IEnumerable types)         {             var implementations = types.Where(/* lambda to identify instantiable types which implement this interface */                 .Select(x = CreateInstance(x));             return implementations;         }         public IEnumerable GetLoadedImplementations()         {             var loadedTypes = GetLoadedTypes();             var implementations = GetImplementations(loadedTypes);             return implementations;         }         private T CreateInstance(Type type)         {             T instance = default(T);             var constructor = type.GetConstructor(Type.EmptyTypes);             if (/* valid to instantiate test */)             {                 object constructed = constructor.Invoke(null);                 instance = (T)constructed;             }             return instance;         }     } It seems useful to me to have my CreateInstance(Type) function implemented as an extension method so I can reuse it later and simplify the code of my factory, but I can't figure out how to return a strongly typed value from that extension method. I realize I could just return an object:     public static class TypeExtensions     {         public object CreateInstance(this Type type)         {             var constructor = type.GetConstructor(Type.EmptyTypes);             return /* valid to instantiate test */ ? constructor.Invoke(null) : null;         }     } Is it possible to have an extension method create a signature per instance of the type it extends? My perfect code would be this, which avoids having to cast the result of the call to CreateInstance():     Type type = typeof(MyParameterlessConstructorImplementingType);     MyParameterlessConstructorImplementingType usable = type.CreateInstance();

    Read the article

  • find word and score based on positions

    - by ryder1211212
    hey guys i have a textfile i have divided it into 4 parts. i want to search each part for the words that appear in each part and score that word exmaple welcome to the national basketball finals,the basketball teams here today have come a long way. without much delay lets play basketball. i will want to return national = 1 as it appears only in one part etc am working on determining text context using word position. am working with c# and not very good in text processing basically if a word appears in the 4 sections it scores 4 if a word appears in the 3 sections it scores 3 if a word appears in the 2 sections it scores 2 if a word appears in the 1 section it scores 1 thanks in advance so far i have this var s = "welcome to the national basketball finals,the basketball teams here today have come a long way. without much delay lets play basketball. "; var numberOfParts = 4; var eachPartLength = s.Length / numberOfParts; var parts = new List<string>(); var words = Regex.Split(s, @"\W").Where(w => w.Length > 0); // this splits all words, removes empty strings var wordsIndex = 0; for (int i = 0; i < numberOfParts; i++) { var sb = new StringBuilder(); while (sb.Length < eachPartLength && wordsIndex < words.Count()) { sb.AppendFormat("{0} ", words.ElementAt(wordsIndex)); wordsIndex++; } // here you have the part Response.Write("[{0}]"+ sb); parts.Add(sb.ToString()); var allwords = parts.SelectMany(p => p.Split(' ').Distinct()); var wordsInAllParts = allwords.Where(w => parts.All(p => p.Contains(w))).Distinct();

    Read the article

  • C# Tupel group limitation

    - by user609511
    How can i controll the loop of Tupel Repeatation ? Someone has give me a hint about my algorithm. I modified a little bit his algorithm. int LimCol = Convert.ToInt32(LimitColis); result = oListTUP .GroupBy(x => x.Item1) .Select(g => new { Key = g.Key, Sum = g.Sum(x => x.Item2), Poids = g.Sum(x => x.Item3), }) .Select(p => new { Key = p.Key, Items = Enumerable.Repeat(LimCol , p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, 1)), CalculPoids = p.Poids / (Enumerable.Repeat(LimCol, p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, 1))).Count() }) .SelectMany(p => p.Items.Select(i => Tuple.Create(p.Key, i, p.CalculPoids))) .ToList(); foreach (var oItem in result) { Label1.Text += oItem.Item1 + "--" + oItem.Item2 + "--" + oItem.Item3 + "<br>"; } the result with LimCol = 3 as you can see i colored with red is the problem. i expected: 0452632--3--3,75 0452632--3--3,75 0452632--3--3,75 0452632--3--3,75 essai 49--3--79,00 essai 49--2--79,00 Thanks you in advance

    Read the article

  • Linq to Entities custom ordering via position mapping table

    - by Bigfellahull
    Hi, I have a news table and I would like to implement custom ordering. I have done this before via a positional mapping table which has newsIds and a position. I then LEFT OUTER JOIN the position table ON news.newsId = position.itemId with a select case statement CASE WHEN [position] IS NULL THEN 9999 ELSE [position] END and order by position asc, articleDate desc. Now I am trying to do the same with Linq to Entities. I have set up my tables with a PK, FK relationship so that my News object has an Entity Collection of positions. Now comes the bit I can't work out. How to implement the LEFT OUTER JOIN. I have so far: var query = SelectMany (n => n.Positions, (n, s) => new { n, s }) .OrderBy(x => x.s.position) .ThenByDescending(x => x.n.articleDate) .Select(x => x.n); This kinda works. However this uses a INNER JOIN so not what I am after. I had another idea: ret = ret.OrderBy(n => n.ShufflePositions.Select(s => s.position)); However I get the error DbSortClause expressions must have a type that is order comparable. I also tried ret = ret.GroupJoin(tse.ShufflePositions, n => n.id, s => s.itemId, (n, s) => new { n, s }) .OrderBy(x => x.s.Select(z => z.position)) .ThenByDescending(x => x.n.articleDate) .Select(x => x.n); but I get the same error! If anyone can help me out, it would be much appreciated!

    Read the article

  • How to get nested chain of objects in Linq and MVC2 application?

    - by Anders Svensson
    I am getting all confused about how to solve this problem in Linq. I have a working solution, but the code to do it is way too complicated and circular I think: I have a timesheet application in MVC 2. I want to query the database that has the following tables (simplified): Project Task TimeSegment The relationships are as follows: A project can have many tasks and a task can have many timesegments. I need to be able to query this in different ways. An example is this: A View is a report that will show a list of projects in a table. Each project's tasks will be listed followed by a Sum of the number of hours worked on that task. The timesegment object is what holds the hours. Here's the View: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Report.Master" Inherits="System.Web.Mvc.ViewPage<Tidrapportering.ViewModels.MonthlyReportViewModel>" %> <asp:Content ID="Content1" ContentPlaceHolderID="TitleContent" runat="server"> Månadsrapport </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server"> <h1> Månadsrapport</h1> <div style="margin-top: 20px;"> <span style="font-weight: bold">Kund: </span> <%: Model.Customer.CustomerName %> </div> <div style="margin-bottom: 20px"> <span style="font-weight: bold">Period: </span> <%: Model.StartDate %> - <%: Model.EndDate %> </div> <div style="margin-bottom: 20px"> <span style="font-weight: bold">Underlag för: </span> <%: Model.Employee %> </div> <table class="mainTable"> <tr> <th style="width: 25%"> Projekt </th> <th> Specifikation </th> </tr> <% foreach (var project in Model.Projects) { %> <tr> <td style="vertical-align: top; padding-top: 10pt; width: 25%"> <%:project.ProjectName %> </td> <td> <table class="detailsTable"> <tr> <th> Aktivitet </th> <th> Timmar </th> <th> Ex moms </th> </tr> <% foreach (var task in project.CurrentTasks) {%> <tr class="taskrow"> <td class="task" style="width: 40%"> <%: task.TaskName %> </td> <td style="width: 30%"> <%: task.TaskHours.ToString()%> </td> <td style="width: 30%"> <%: String.Format("{0:C}", task.Cost)%> </td> </tr> <% } %> </table> </td> </tr> <% } %> </table> <table class="summaryTable"> <tr> <td style="width: 25%"> </td> <td> <table style="width: 100%"> <tr> <td style="width: 40%"> Totalt: </td> <td style="width: 30%"> <%: Model.TotalHours.ToString() %> </td> <td style="width: 30%"> <%: String.Format("{0:C}", Model.TotalCost)%> </td> </tr> </table> </td> </tr> </table> <div class="price"> <table> <tr> <td>Moms: </td> <td style="padding-left: 15px;"> <%: String.Format("{0:C}", Model.VAT)%> </td> </tr> <tr> <td>Att betala: </td> <td style="padding-left: 15px;"> <%: String.Format("{0:C}", Model.TotalCostAndVAT)%> </td> </tr> </table> </div> </asp:Content> Here's the action method: [HttpPost] public ActionResult MonthlyReports(FormCollection collection) { MonthlyReportViewModel vm = new MonthlyReportViewModel(); vm.StartDate = collection["StartDate"]; vm.EndDate = collection["EndDate"]; int customerId = Int32.Parse(collection["Customers"]); List<TimeSegment> allTimeSegments = GetTimeSegments(customerId, vm.StartDate, vm.EndDate); vm.Projects = GetProjects(allTimeSegments); vm.Employee = "Alla"; vm.Customer = _repository.GetCustomer(customerId); vm.TotalCost = vm.Projects.SelectMany(project => project.CurrentTasks).Sum(task => task.Cost); //Corresponds to above foreach vm.TotalHours = vm.Projects.SelectMany(project => project.CurrentTasks).Sum(task => task.TaskHours); vm.TotalCostAndVAT = vm.TotalCost * 1.25; vm.VAT = vm.TotalCost * 0.25; return View("MonthlyReport", vm); } And the "helper" methods: public List<TimeSegment> GetTimeSegments(int customerId, string startdate, string enddate) { var timeSegments = _repository.TimeSegments .Where(timeSegment => timeSegment.Customer.CustomerId == customerId) .Where(timeSegment => timeSegment.DateObject.Date >= DateTime.Parse(startdate) && timeSegment.DateObject.Date <= DateTime.Parse(enddate)); return timeSegments.ToList(); } public List<Project> GetProjects(List<TimeSegment> timeSegments) { var projectGroups = from timeSegment in timeSegments group timeSegment by timeSegment.Task into g group g by g.Key.Project into pg select new { Project = pg.Key, Tasks = pg.Key.Tasks }; List<Project> projectList = new List<Project>(); foreach (var group in projectGroups) { Project p = group.Project; foreach (var task in p.Tasks) { task.CurrentTimeSegments = timeSegments.Where(ts => ts.TaskId == task.TaskId).ToList(); p.CurrentTasks.Add(task); } projectList.Add(p); } return projectList; } Again, as I mentioned, this works, but of course is really complex and I get confused myself just looking at it even now that I'm coding it. I sense there must be a much easier way to achieve what I want. Basically you can tell from the View what I want to achieve: I want to get a collection of projects. Each project should have it's associated collection of tasks. And each task should have it's associated collection of timesegments for the specified date period. Note that the projects and tasks selected must also only be the projects and tasks that have the timesegments for this period. I don't want all projects and tasks that have no timesegments within this period. It seems the group by Linq query beginning the GetProjects() method sort of achieves this (if extended to have the conditions for date and so on), but I can't return this and pass it to the view, because it is an anonymous object. I also tried creating a specific type in such a query, but couldn't wrap my head around that either... I hope there is something I'm missing and there is some easier way to achieve this, because I need to be able to do several other different queries as well eventually. I also don't really like the way I solved it with the "CurrentTimeSegments" properties and so on. These properties don't really exist on the model objects in the first place, I added them in partial classes to have somewhere to put the filtered results for each part of the nested object chain... Any ideas?

    Read the article

  • Entity Framework LINQ Query using Custom C# Class Method - Once yes, once no - because executing on the client or in SQL?

    - by BrooklynDev
    I have two Entity Framework 4 Linq queries I wrote that make use of a custom class method, one works and one does not: The custom method is: public static DateTime GetLastReadToDate(string fbaUsername, Discussion discussion) { return (discussion.DiscussionUserReads.Where(dur => dur.User.aspnet_User.UserName == fbaUsername).FirstOrDefault() ?? new DiscussionUserRead { ReadToDate = DateTime.Now.AddYears(-99) }).ReadToDate; } The linq query that works calls a from after a from, the equivalent of SelectMany(): from g in oc.Users.Where(u => u.aspnet_User.UserName == fbaUsername).First().Groups from d in g.Discussions select new { UnReadPostCount = d.Posts.Where(p => p.CreatedDate > DiscussionRepository.GetLastReadToDate(fbaUsername, p.Discussion)).Count() }; The query that does not work is more like a regular select: from d in oc.Discussions where d.Group.Name == "Student" select new { UnReadPostCount = d.Posts.Where(p => p.CreatedDate > DiscussionRepository.GetLastReadToDate(fbaUsername, p.Discussion)).Count(), }; The error I get is: LINQ to Entities does not recognize the method 'System.DateTime GetLastReadToDate(System.String, Discussion)' method, and this method cannot be translated into a store expression. My question is, why am I able to use my custom GetLastReadToDate() method in the first query and not the second? I suppose this has something to do with what gets executed on the db server and what gets executed on the client? These queries seem to use the GetLastReadToDate() method so similarly though, I'm wondering why would work for the first and not the second, and most importantly if there's a way to factor common query syntax like what's in the GetLastReadToDate() method into a separate location to be reused in several different places LINQ queries. Please note all these queries are sharing the same object context.

    Read the article

  • managing classes when everything is relative to a user in nhibernate (orm)

    - by Schotime
    Firstly I have three entities. Users, Roles, Items A user can have multiple Roles. An item gets assigned to one or more roles. Therefore a user will have access to a distinct set of items. Now there is a few ways I can see this working. There is a Collection on Users which has Roles via a many-to-many assoc. Then each Role in this collection will have its own collection of Items. So for each user I would have to get the User (using nhib and fetch the roles and items with it) then either do a selectMany on the Items in each Role to get all the Items for the user or do a couple of foreach's to port the data to a view or dto model. Create a db trigger to automatically insert into another table that just has the relationship between user and items so that on my User entity I only have a Items collections which has all the items assigned to me. Some other way that i can't think of yet, because I'm new to nHibernate. Now i know that the trigger doesn't feel right but I'm not sure how to do this. We also have some hierarchy later where a user may be in charge of a group of users. If anyone could shed some light on how they go about these scenarios in nhibernate or another orm that would be great, or point be in a direction. I know that in the past you would have to enter all combinations into a table so that the query worked, but when you know sql its not too bad. If you need any other info then let me know. Cheers

    Read the article

  • LINQ to SQL Converter

    - by user609511
    How can I convert My LINQ to SQL ? i have this LINQ statement: int LimCol = Convert.ToInt32(LimitColis); result = oListTUP .GroupBy(x => new { x.Item1, x.Item2, x.Item3, x.Item4, x.Item5 }) .Select(g => new { Key = g.Key, Sum = g.Sum(x => x.Item6), Poids = g.Sum(x => x.Item7), }) .Select(p => new { Key = p.Key, Items = Enumerable.Repeat(LimCol, p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, p.Sum % LimCol > 0 ? 1 : 0)), CalculPoids = p.Poids / Enumerable.Repeat(LimCol, p.Sum / LimCol).Concat(Enumerable.Repeat(p.Sum % LimCol, p.Sum % LimCol > 0 ? 1 : 0)).Count() }) .SelectMany(p => p.Items.Select(i => Tuple.Create(p.Key.Item1, p.Key.Item2, p.Key.Item3, p.Key.Item4, p.Key.Item5, i, p.CalculPoids))) .ToList(); } It works well, but somehow want to push it and it become too complicated, so I want to convert it into Pure SQL. I have tried SQL Profiler and LinqPad, but neither shows me the SQL. How can I see the SQL code from My LINQ ? Thank you in advance.

    Read the article

  • EF4 querying through the generations

    - by Hans Kesting
    I have a model withs Parents, Children and Grandchildren, in a many-to-many relationship. Using this article I created POCO classes that work fine, except for one thing I can't yet figure out. When I query the Parents or Children directly using LINQ, the SQL reflects the LINQ query (a .Count() executes a COUNT in the database and so on) - fine. The Parent class has a Children property, to access it's children. But (and now for the problem) this doesn't expose an IQueryable interface but an ICollection. So when I access the Children property on a particular parent all the Parent's Children are read. Even worse, when I access the Grandchildren (theParent.Children.SelectMany(child => child.GrandChildren).Count()) then for each and every child a separate request is issued to select it's grandchildren. Changing the type of the Children property from ICollection to IQueryable doesn't solve this. Apart from missing needed methods like Add() and Remove(), EF just doesn't recognize the property then. Are there correct ways (as in: low database interaction) of querying through children (and what are they)? Or is this just not possible?

    Read the article

  • How to filter List<T> with LINQ and Reflection

    - by Ehsan Sajjad
    i am getting properties via reflection and i was doing like this to iterate on the list. private void HandleListProperty(object oldObject, object newObject, string difference, PropertyInfo prop) { var oldList = prop.GetValue(oldObject, null) as IList; var newList = prop.GetValue(newObject, null) as IList; if (prop.PropertyType == typeof(List<DataModel.ScheduleDetail>)) { List<DataModel.ScheduleDetail> ScheduleDetailsOld = oldList as List<DataModel.ScheduleDetail>; List<DataModel.ScheduleDetail> ScheduleDetailsNew = newList as List<DataModel.ScheduleDetail>; var groupOldSchedules = ScheduleDetailsOld .GroupBy(x => x.HomeHelpID) .SelectMany(s => s.DistinctBy(d => d.HomeHelpID) .Select(h => new { h.HomeHelpID, h.HomeHelpName })); } } Now i am making it generic because there will be coming different types of Lists and i don't want to put if conditions this way i want to write generic code to handle any type of list. I came up with this way: private void HandleListProperty(object oldObject, object newObject, string difference, PropertyInfo prop) { var oldList = prop.GetValue(oldObject, null) as IList; var newList = prop.GetValue(newObject, null) as IList; var ListType = prop.PropertyType; var MyListInstance = Activator.CreateInstance(ListType); MyListInstance = oldList; } i am able to get the items in MyListInstance but as the type will come at runtime i am not getting how to write linq query to filter them, any ideah how to do.

    Read the article

< Previous Page | 1 2 3  | Next Page >