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  • How do I add ROW_NUMBER to a LINQ query or Entity?

    - by Whozumommy
    I'm stumped by this easy data problem. I'm using the Entity framework and have a database of products. My results page returns a paginated list of these products. Right now my results are ordered by the number of sales of each product, so my code looks like this: return Products.OrderByDescending(u => u.Sales.Count()); This returns an IQueryable dataset of my entities, sorted by the number of sales. I want my results page to show the rank of each product (in the dataset). My results should look like this: Page #1 1. Bananas 2. Apples 3. Coffee Page #2 4. Cookies 5. Ice Cream 6. Lettuce I'm expecting that I just want to add a column in my results using the SQL ROW_NUMBER variable...but I don't know how to add this column to my results datatable. My resulting page does contain a foreach loop, but since I'm using a paginated set I'm guessing using that number to fake a ranking number would NOT be the best approach. So my question is, how do I add a ROW_NUMBER column to my query results in this case?

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  • I'm trying to handle the updates on 2 related tables in one DetailsView using Jquery and Linq, and h

    - by Ben Reisner
    Given two related tables (reports, report_fields) where there can be many report_fields entries for each reports entry, I need to allow the user to enter new report_fields, delete existing report_fields, and re-arrange the order. Currently I am using a DetailsView to handle the editing of the reports. I added some logic to handle report_fields, and currently it allows you to succesfully re-arrange the order, but i'm a little stumped as to the best way to add new items, or delete existing items. The basic logic I have is that each report_fields is represented by a . It has a description as the text, and a field for each field in the report_fields table. I use JQuery Sortable to allow the user to re-arrange the LIs. Abbreviated Create Table Statements:(foreign key constraint ignored for brevity) create table report( id integer primary key identity, reportname varchar(250) ) create table report_fields( id integer primary key identity, reportID integer, keyname integer, keyvalue integer, field_order integer ) My abbreviated markup: <asp:DetailsView ...> ... <asp:TemplateField HeaderText="Fields"> <EditItemTemplate> <ul class="MySortable"> <asp:Repeater ID="Repeater1" runat="server" DataSource='<%# Eval("report_fields") %>'> <ItemTemplate> <li> <%# Eval("keyname") %>: <%# Eval("keyvalue") %> <input type="hidden" name="keyname[]" value='<%# Eval("keyname") %>' /> <input type="hidden" name="keyvalue[]" value='<%# Eval("keyvalue") %>' /> </li> </ItemTemplate> </asp:Repeater> </ul> </EditItemTemplate> </asp:TemplateField> </asp:DetailsView> <asp:LinqDataSource ID="LinqDataSource2" onupdating="LinqDataSource2_Updating" table=reports ... /> $(function() { $(".MySortable").sortable({ placeholder: 'MySortable-highlight' }).disableSelection(); }); Code Behind Class: public partial class Administration_AddEditReport protected void LinqDataSource2_Updating(object sender, LinqDataSourceUpdateEventArgs e) { report r = (report)e.NewObject; MyDataContext dc = new MyDataContext(); var fields = from f in dc.report_fields where f.reportID == r.id select f; dc.report_fields.DeleteAllOnSubmit(fields); NameValueCollection nvc = Request.Params; string[] keyname = nvc["keyname[]"].Split(','); string[] keyvalue = nvc["keyvalue[]"].Split(','); for (int i = 0; i < keyname.Length; i++) { report_field rf = new report_field(); rf.reportID = r.id; rf.keyname = keyname[i]; rf.keyvalue = keyvalue[i]; rf.field_order = i; dc.report_fields.InsertOnSubmit(rf); } dc.SubmitChanges(); } }

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  • LINQ TO SQL error: An attempt has been made to Attach or Add an entity that is not new...

    - by Collin Estes
    "An attempt has been made to Attach or Add an entity that is not new, perhaps having been loaded from another DataContext. This is not supported." I have scene a lot of solutions dealing with the Attach() method but I'm just trying to add in a new record. Not sure what is going on. Here is my code, It is failing on the star'd line.: try { LINQDataContext datacontext = new LINQDataContext(); TrackableItem ti = datacontext.TrackableItems.FirstOrDefault(_t => _t.pkId == obj.fkTrackableItemId); arcTrackableItem ati = new arcTrackableItem(); ati.barcode = ti.barcode; ati.dashNumber = ti.dashNumber; ati.dateDown = ti.dateDown; ati.dateUp = ti.dateUp; ati.fkItemStatusId = ti.fkItemStatusId; ati.fkItemTypeId = ti.fkItemTypeId; ati.partNumber = ti.partNumber; ati.serialNumber = ti.serialNumber; ati.archiveDate = DateTime.Now; datacontext.arcTrackableItems.InsertOnSubmit(ati); datacontext.SubmitChanges(); arcPWR aItem = new arcPWR(); aItem.comments = obj.comments; aItem.fkTrackableItemId = ati.pkId; aItem.fkPWRStatusId = obj.fkPWRStatusId; aItem.PwrStatus = obj.PwrStatus; **datacontext.arcPWRs.InsertOnSubmit(aItem);** datacontext.SubmitChanges();

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  • Is this Where condition in Linq-to-sql join correct?

    - by Pandiya Chendur
    I have the following Iqueryable method to show details of a singl material, public IQueryable<Materials> GetMaterial(int id) { return from m in db.Materials join Mt in db.MeasurementTypes on m.MeasurementTypeId equals Mt.Id where m.Mat_id equals id select new Materials() { Id = Convert.ToInt64(m.Mat_id), Mat_Name = m.Mat_Name, Mes_Name = Mt.Name, }; } Any suggestion....

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  • How do you compare dates in a LINQ query?

    - by Gina
    I am tring to compare a date from a asp calendar control to a date in the table.... here's what i have... it doesn't like the == ? var query = from details in db.TD_TravelCalendar_Details where details.StartDate == calStartDate.SelectedDate && details.EndDate == calEndDate.SelectedDate select details;

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  • LINQ to SQL: ExecuteQuery not working when performing a parameterized query.

    - by ajbeaven
    I have a weird problem with ExecuteQuery in that it isn't working when performing a parameterized query. The following returns 1 record: db.ExecuteQuery<Member>(@"SELECT * FROM Member INNER JOIN aspnet_Users ON Member.user_id = aspnet_Users.UserId WHERE [aspnet_Users].[UserName] = 'Marina2'"); However, the parameterized version returns no results: db.ExecuteQuery<Member>(@"SELECT * FROM Member INNER JOIN aspnet_Users ON Member.user_id = aspnet_Users.UserId WHERE [aspnet_Users].[UserName] = '{0}'", "Marina2"); What am I doing wrong?

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  • What is the best way in assigning foreign key when using entity framework & LINQ to Entities?

    - by Abdel Olakara
    Hi all, I need to know the best practice of creating an entity object and assigning the foreign key. Here is my scenario. I have a Product table with pid,name,unit_price etc.. I also have a Rating table with pid (foregin key),rate,votes etc... Currently i am doing the following to create the rating object: var prod = entities.Product.First(p => p.product_id == pid); prod.Rating.Load(); if (prod.Rating != null) { log.Info("Rating already exists!"); // set values and Calcuate the score } else { log.Info("New Rating!!!"); Rating rating = new Rating(); // set values and do inital calculation prod.Rating = rating; } entities.SaveChanges(); Even though this works fine, i would like to know the best practice in doing these kind of assignment. Thanks for your suggestions and info. Best Regards, Abdel Olakara

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  • An attempt has been made to Attach or Add an entity that is not new Linq to Sql error

    - by Collin Oconnor
    I have a save function for my order entity that looks like this and it breaks on the sumbmitChanges line: public void SaveOrder ( Order order ) { if (order.OrderId == 0) orderTable.InsertOnSubmit(order); else if (orderTable.GetOriginalEntityState(order) == null) { orderTable.Attach(order); orderTable.Context.Refresh(RefreshMode.KeepCurrentValues , order); } orderTable.Context.SubmitChanges(); } The order entity contains two other entities; an Address entity and a credit card entity. Now i want these two entities to be null sometimes. Now my guess for why this is throwing an error is because that both of these entites that are inside order are null. If this is the case, How can I insert an new order into the database with both entities (Address and creditCard) being null.

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  • LINQ: why does this query not work on an ArrayList?

    - by Benny
    public static ArrayList GetStudentAsArrayList() { ArrayList students = new ArrayList { new Student() { RollNumber = 1,Name ="Alex " , Section = 1 ,HostelNumber=1 }, new Student() { RollNumber = 2,Name ="Jonty " , Section = 2 ,HostelNumber=2 } }; return students; } The following code doesn't compile. The error is ArrayList is not IEnumerable ArrayList lstStudents = GetStudentAsArrayList(); var res = from r in lstStudents select r; This compiles: ArrayList lstStudents = GetStudentAsArrayList(); var res = from Student r in lstStudents select r; Can anybody explain what the difference is between these two snippets? Why the second works?

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  • Locked DataGridView. Linq is a problem ?

    - by phenevo
    Hi, I get the collection from webservice: var allPlaceHolders = (from ph in new MyService().GetPlaceHolders() select ph).Select(l => new { Code = l.Code, Name = l.Name, Related = false }).ToList(); dgPlaceHoldersAdd.DataSource = allPlaceHolders; Designer.cs: this.dgPlaceHoldersAdd.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize; this.dgPlaceHoldersAdd.Location = new System.Drawing.Point(3, 54); this.dgPlaceHoldersAdd.Name = "dgPlaceHoldersAdd"; this.dgPlaceHoldersAdd.RowHeadersVisible = false; this.dgPlaceHoldersAdd.Size = new System.Drawing.Size(286, 151); this.dgPlaceHoldersAdd.TabIndex = 15; The problem is, that I can't changing value of checkBox column. I has enabled AutoGeneratedColumns (In datagridview at start there is not any column)

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  • What's a clean way to break up a DataTable into chunks of a fixed size with Linq?

    - by Michael Haren
    Update: Here's a similar question Suppose I have a DataTable with a few thousand DataRows in it. I'd like to break up the table into chunks of smaller rows for processing. I thought C#3's improved ability to work with data might help. This is the skeleton I have so far: DataTable Table = GetTonsOfData(); // Chunks should be any IEnumerable<Chunk> type var Chunks = ChunkifyTableIntoSmallerChunksSomehow; // ** help here! ** foreach(var Chunk in Chunks) { // Chunk should be any IEnumerable<DataRow> type ProcessChunk(Chunk); } Any suggestions on what should replace ChunkifyTableIntoSmallerChunksSomehow? I'm really interested in how someone would do this with access C#3 tools. If attempting to apply these tools is inappropriate, please explain! Update 3 (revised chunking as I really want tables, not ienumerables; going with an extension method--thanks Jacob): Final implementation: Extension method to handle the chunking: public static class HarenExtensions { public static IEnumerable<DataTable> Chunkify(this DataTable table, int chunkSize) { for (int i = 0; i < table.Rows.Count; i += chunkSize) { DataTable Chunk = table.Clone(); foreach (DataRow Row in table.Select().Skip(i).Take(chunkSize)) { Chunk.ImportRow(Row); } yield return Chunk; } } } Example consumer of that extension method, with sample output from an ad hoc test: class Program { static void Main(string[] args) { DataTable Table = GetTonsOfData(); foreach (DataTable Chunk in Table.Chunkify(100)) { Console.WriteLine("{0} - {1}", Chunk.Rows[0][0], Chunk.Rows[Chunk.Rows.Count - 1][0]); } Console.ReadLine(); } static DataTable GetTonsOfData() { DataTable Table = new DataTable(); Table.Columns.Add(new DataColumn()); for (int i = 0; i < 1000; i++) { DataRow Row = Table.NewRow(); Row[0] = i; Table.Rows.Add(Row); } return Table; } }

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  • Why do LINQ to Entities does not recognize certain Methods?

    - by Luiscencio
    Why cant I do this: usuariosEntities usersDB = new usuariosEntities(); foreach (DataGridViewRow user in dgvUsuarios.Rows) { var rowtoupdate = usersDB.usuarios.Where( u => u.codigo_usuario == Convert.ToInt32(user.Cells[0].Value) ).First(); rowtoupdate.password = user.Cells[3].Value.ToString(); } usersDB.SaveChanges(); And have to do this: usuariosEntities usersDB = new usuariosEntities(); foreach (DataGridViewRow user in dgvUsuarios.Rows) { int usercode = Convert.ToInt32(user.Cells[0].Value); var rowtoupdate = usersDB.usuarios.Where(u => u.codigo_usuario == usercode).First(); rowtoupdate.password = user.Cells[3].Value.ToString(); } usersDB.SaveChanges(); I must admint it is a more readable code but why cant this be done?

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  • How do I get a linq to sql group by query into the asp.net mvc view?

    - by Brad Wetli
    Sorry for the newbie question, but I have the following query that groups parking spaces by their garage, but I can't figure out how to iterate the data in the view. I guess I should strongly type the view but am a newbie and having lots of problems figuring this out. Any help would be appreciated. Public Function FindAllSpaces() Implements ISpaceRepository.FindAllSpaces Dim query = _ From s In db.spaces _ Order By s.name Ascending _ Group By s.garageid Into spaces = Group _ Order By garageid Ascending Return query End Function The controller is taking the query object as is and putting it into the viewdata.model and as stated the view is not currently strongly typed as I haven't been able to figure out how to do this. I have run the query successfully in linqpad.

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  • Why does LINQ-to-Entites recognize my custom method?

    - by BlueRaja The Green Unicorn
    This works: (from o in Entities.WorkOrderSet select o) .Where(MyCustomMethod); This does not: (from o in Entities.WorkOrderSet select new { WorkOrder = o }) .Where(o => MyCustomMethod(o.WorkOrder); I understand why the second doesn't work - but why in the world does the first work!? Shouldn't I get a "custom method not recognized?" For reference, here is MyCustomMethod public bool MyCustomMethod(WorkOrder workOrder) { return !workOrder.WorkOrderNum.StartsWith("A", StringComparison.CurrentCultureIgnoreCase); }

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  • linq-to-sql "an attempt has been made to attach or add an entity that is not new"?

    - by Curtis White
    I've been getting several errors: cannot add an entity with a key that is already in use An attempt has been made to attach or add an entity that is not new, perhaps having been loaded from another datacontext In case 1, this stems from trying to set the key for an entity versus the entity. In case 2, I'm not attaching an entity but I am doing this: MyParent.Child = EntityFromOtherDataContext; I've been using using the pattern of wrap everything with a using datacontext. In my case, I am using this in a web forms scenario, and obviously moving the datacontext object to a class wide member variables solves this. My questions are thus 2 fold: How can I get rid of these errors and not have to structure my program in an odd way or pass the datacontext around while keeping the local-wrap pattern? I assume I could make another hit to the database but that seems very inefficient. Would most people recommend that moving the datacontext to the class wide scope is desirable for web pages?

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  • How can i filter a list of objects using lamda expression?

    - by Colour Blend
    I know i shouldn't have id's with the same value. This is just fictitious, so overlook that. I have: List<Car> carList = new List<Car>(); carList.Add(new Car() { id = 1, name = "Honda" }); carList.Add(new Car() { id = 2, name = "Toyota" }); carList.Add(new Car() { id = 1, name = "Nissan" }); I want to use Lamda Expression to retreive all cars that have an id of 1. Anticipated Result: -- Id: 1, Name: Honda -- Id: 1, Name: Nissan The problem is more filtering an object list based on a foriegn key. Please help me.

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  • LINQ to SQL -- Can't modify return type of stored procedure.

    - by Kyle Ryan
    When I drag a particular stored procedure into the VS 2008 dbml designer, it shows up with Return Type set to "none", and it's read only so I can't change it. The designer code shows it as returning an int, and if I change that manually, it just gets undone on the next build. But with another (nearly identical) stored procedure, I can change the return type just fine (from "Auto Generated Type" to what I want.) I've run into this problem on two separate machines. Any idea what's going on? Here's the stored procedure that works: USE [studio] GO /****** Object: StoredProcedure [dbo].[GetCourseAnnouncements] Script Date: 05/29/2009 09:44:51 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER OFF GO CREATE PROCEDURE [dbo].[GetCourseAnnouncements] @course int AS SELECT * FROM Announcements WHERE Announcements.course = @course RETURN And this one doesn't: USE [studio] GO /****** Object: StoredProcedure [dbo].[GetCourseAssignments] Script Date: 05/29/2009 09:45:32 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER OFF GO CREATE PROCEDURE [dbo].[GetCourseAssignments] @course int AS SELECT * FROM Assignments WHERE Assignments.course = @course ORDER BY date_due ASC RETURN

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  • Can I clone an IQueryable in linq? For UNION purposes?

    - by user169867
    I have a table of WorkOrders. The table has a PrimaryWorker & PrimaryPay field. It also has a SecondaryWorker & SecondaryPay field (which can be null). I wish to run 2 very similar queries & union them so that it will return a Worker Field & Pay field. So if a single WorkOrder record had both the PrimaryWorker and SecondaryWorker field populated I would get 2 records back. The "where clause" part of these 2 queries is very similar and long to construct. Here's a dummy example var q = ctx.WorkOrder.Where(w => w.WorkDate >= StartDt && w.WorkDate <= EndDt); if(showApprovedOnly) { q = q.Where(w => w.IsApproved); } //...more filters applied Now I also have a search flag called "hideZeroPay". If that's true I don't want to include the record if the worker was payed $0. But obviously for 1 query I need to compare the PrimaryPay field and in the other I need to compare the SecondaryPay field. So I'm wondering how to do this. Can I clone my base query "q" and make a primary & secondary worker query out of it and then union those 2 queries together? I'd greatly appreciate an example of how to correctly handle this. Thanks very much for any help.

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  • Expand in linq not loading inner data collections from service.

    - by Kit
    I am seeing odd behavior with service queries! I am using MVVM pattern for a silverlight 3 app on 3.5 framework and Dataservices 1.5. The following code eager loads correctly the parent object and the child heirarchy perfectly IF and ONLY IF I am preloading the data. But I would like to fetch a different set of the parent object (and its child heirarchy) on different button clicks. What I am seeing is that on button click, only the parent object is retrieved, and the child heirarchy contains nothing. Any suggestions? Any ideas how to tackle this? Thanks all. The method: DataServiceQuery serviceQuery = (DataServiceQuery)(from m1 in dbEntities.gis_Region.Expand("gis_RegionValue/gis_Measure") where m1.RegionGuid == new Guid(regionGuid) select m1); serviceQuery.BeginExecute(GetRegionDetailAsyncResult, serviceQuery); The wired Async Result: DataServiceQuery query = (DataServiceQuery)result.AsyncState; gis_Region region = query.EndExecute(result).First();

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  • Is there a better way to write this LINQ query?

    - by Raj Aththanayake
    Hi Is there a better simplified way to write this query. My logic is if collection contains customer ids and countrycodes, do the query ordey by customer id ascending. If there are no contain id in CustIDs then do the order by customer name. Is there a better way to write this query? I'm not really familiar with complex lambdas. var custIdResult = (from Customer c in CustomerCollection where (c.CustomerID.ToLower().Contains(param.ToLower()) && (countryCodeFilters.Any(item => item.Equals(c.CountryCode))) ) select c).ToList(); if (custIdResult.Count > 0) { return from Customer c in custIdResult where ( c.CustomerName.ToLower().Contains(param.ToLower()) && countryCodeFilters.Any(item => item.Equals(c.CountryCode))) orderby c.CustomerID ascending select c; } else { return from Customer c in CustomerCollection where (c.CustomerName.ToLower().Contains(param.ToLower()) && countryCodeFilters.Any(item => item.Equals(c.CountryCode))) orderby c.CustomerName descending select c; }

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  • How can I implement NotOfType<T> in LINQ that has a nice calling syntax?

    - by Lette
    I'm trying to come up with an implementation for NotOfType, which has a readable call syntax. NotOfType should be the complement to OfType<T> and would consequently yield all elements that are not of type T My goal was to implement a method which would be called just like OfType<T>, like in the last line of this snippet: public abstract class Animal {} public class Monkey : Animal {} public class Giraffe : Animal {} public class Lion : Animal {} var monkey = new Monkey(); var giraffe = new Giraffe(); var lion = new Lion(); IEnumerable<Animal> animals = new Animal[] { monkey, giraffe, lion }; IEnumerable<Animal> fewerAnimals = animals.NotOfType<Giraffe>(); However, I can not come up with an implementation that supports that specific calling syntax. This is what I've tried so far: public static class EnumerableExtensions { public static IEnumerable<T> NotOfType<T>(this IEnumerable<T> sequence, Type type) { return sequence.Where(x => x.GetType() != type); } public static IEnumerable<T> NotOfType<T, TExclude>(this IEnumerable<T> sequence) { return sequence.Where(x => !(x is TExclude)); } } Calling these methods would look like this: // Animal is inferred IEnumerable<Animal> fewerAnimals = animals.NotOfType(typeof(Giraffe)); and // Not all types could be inferred, so I have to state all types explicitly IEnumerable<Animal> fewerAnimals = animals.NotOfType<Animal, Giraffe>(); I think that there are major drawbacks with the style of both of these calls. The first one suffers from a redundant "of type/type of" construct, and the second one just doesn't make sense (do I want a list of animals that are neither Animals nor Giraffes?). So, is there a way to accomplish what I want? If not, could it be possible in future versions of the language? (I'm thinking that maybe one day we will have named type arguments, or that we only need to explicitly supply type arguments that can't be inferred?) Or am I just being silly?

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