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  • nested linq-to-sql queries

    - by ile
    var result = ( from contact in db.Contacts join user in db.Users on contact.CreatedByUserID equals user.UserID orderby contact.ContactID descending select new ContactListView { ContactID = contact.ContactID, FirstName = contact.FirstName, LastName = contact.LastName, Company = (from field in contact.XmlFields.Descendants("Company") select field.Value).SingleOrDefault().ToString() }).Take(10); Here I described how my database tables look like. So, contacts table has one field that is xml type. In that field is stored Company filename and I need to read it. I tried it using this way: Company = (from field in contact.XmlFields.Descendants("Company") select field.Value).SingleOrDefault().ToString() }).Take(10); but I get following error: Member access 'System.String Value' of 'System.Xml.Linq.XElement' not legal on type 'System.Collections.Generic.IEnumerable`1[System.Xml.Linq.XElement]. Any solution for this? Thanks in advance, Ile

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  • Loop to LINQ Conversion -

    - by Pino
    Ok I have the following, set-up and working great. These lines of code should do a conversion from DAL Entity (Subsonic) to a ViewModel. IList<ProductOptionModel> OptionsRetData = new List<ProductOptionModel>(); foreach (var CurProductOption in this.ProductOptions) { OptionsRetData.Add(CurProductOption.ToDataModel()); } returnData.Options = OptionsRetData.AsEnumerable(); I'd like to convert this to a LINQ single line statment and came up with the following. returnData.Options = this.ProductOptions.Select(o => o.ToDataModel()); and am recieving the following error. Server Error in '/' Application. Sequence contains no matching element So why does the first statment work but not the LINQ and, what steps can I take to resolve it.

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  • Weighted Average with LINQ

    - by jsmith
    My goal is to get a weighted average from one table, based on another tables primary key. Example Data: Table1 Key WEIGHTED_AVERAGE 0200 0 Table2 ForeignKey LENGTH PCR 0200 105 52 0200 105 60 0200 105 54 0200 105 -1 0200 47 55 I need to get a weighted average based on the length of a segment and I need to ignore values of -1. I know how to do this in SQL, but my goal is to do this in LINQ. It looks something like this in SQL: SELECT Sum(t2.PCR*t2.LENGTH)/Sum(t2.LENGTH) AS WEIGHTED_AVERAGE FROM Table1 t1, Table2 t2 WHERE t2.PCR <> -1 AND t2.ForeinKey = t1.Key; I am still pretty new to LINQ, and having a hard time figuring out how I would translate this. The result weighted average should come out to roughly 55.3. Thank you.

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  • LINQ to SQL Translation

    - by Ben
    Hi, Depending on how I map my linq queries to my domain objects, I get the following error The member 'member' has no supported translation to SQL. This code causes the error: public IQueryable<ShippingMethod> ShippingMethods { get { return from sm in _db.ShippingMethods select new ShippingMethod( sm.ShippingMethodID, sm.Carrier, sm.ServiceName, sm.RatePerUnit, sm.EstimatedDelivery, sm.DaysToDeliver, sm.BaseRate, sm.Enabled ); } } This code works fine: public IQueryable<ShippingMethod> ShippingMethods { get { return from sm in _db.ShippingMethods select new ShippingMethod { Id = sm.ShippingMethodID, Carrier = sm.Carrier, ServiceName = sm.ServiceName, EstimatedDelivery = sm.EstimatedDelivery, DaysToDeliver = sm.DaysToDeliver, RatePerUnit = sm.RatePerUnit, IsEnabled = sm.Enabled, BaseRate = sm.BaseRate }; } } This is my testmethod I am testing with: [TestMethod] public void Test_Shipping_Methods() { IOrderRepository orderRepo = new SqlOrderRepository(); var items = orderRepo.ShippingMethods.Where(x => x.IsEnabled); Assert.IsTrue(items.Count() > 0); } How does the way in which I instantiate my object affect the linq to sql translation? Thanks Ben

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  • LINQ: How to Use RemoveAll without using For loop with Array

    - by CrimsonX
    I currently have a log object I'd like to remove objects from, based on a LINQ query. I would like to remove all records in the log if the sum of the versions within a program are greater than 60. Currently I'm pretty confident that this'll work, but it seems kludgy: for (int index = 0; index < 4; index++) { Log.RemoveAll(log => (log.Program[index].Version[0].Value + log.Program[index].Version[1].Value + log.Program[index].Version[2].Value ) > 60); } The Program is an array of 4 values and version has an array of 3 values. Is there a more simple way to do this RemoveAll in LINQ without using the for loop? Thanks for any help in advance!

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  • Advanced Where Statements in Linq to Entity Framework

    - by JimJams
    Hi, I am wanting to create a Where statement within my Linq statement, but have hit a bit of a stumbling block. I would like to split a string value, and then search using each array item in the Where clause. In my normal Sql statement I would simply loop through the string array, and build up there Where clause then either pass this to a stored procedure, or just execute the sql string. But am not sure how to do this with Linq to Entity? ( From o In db.TableName Where o.Field LIKE Stringvalue Select o ).ToList() Hope you can help. Thanks in advance!

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  • C# Joins/Where with Linq and Lambda

    - by David
    Hello, I'm having trouble with a query written in Linq and Lambda. So far, I'm getting allot of errors here's my code: int id = 1; var query = database.Posts.Join(database.Post_Metas, post => database.Posts.Where(x => x.ID == id), meta => database.Post_Metas.Where(x => x.Post_ID == id), (post, meta) => new { Post = post, Meta = meta }); I'm new to using Linq, so I'm not sure if this query is correct.

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  • Sort and Group in LINQ

    - by Jono
    I apologise in advance if this has been answered before; it seems so fundamental to me yet I haven't turned up the answer in any of my searches. I have a list of string tuples, say (P1,P2) I'd like to know if there's a LINQ statement where I could group by P1 (in ascending order), and have that group contain all the P2 values for the group (in descending order). For input: ("A","B"), ("A","C"), ("D","B") I'd like to get two groups: "A" and "D" (in that order, every time) where group "A" contains "C" and "B" (in that order, every time) and group "D" contains, well, "B". Is this possible with the built-in LINQ classes or do I need to iterate the groups and sort them myself? Sounds like hard work~

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  • Many-To-Many Query with Linq-To-NHibernate

    - by rjygraham
    Ok guys (and gals), this one has been driving me nuts all night and I'm turning to your collective wisdom for help. I'm using Fluent Nhibernate and Linq-To-NHibernate as my data access story and I have the following simplified DB structure: CREATE TABLE [dbo].[Classes]( [Id] [bigint] IDENTITY(1,1) NOT NULL, [Name] [nvarchar](100) NOT NULL, [StartDate] [datetime2](7) NOT NULL, [EndDate] [datetime2](7) NOT NULL, CONSTRAINT [PK_Classes] PRIMARY KEY CLUSTERED ( [Id] ASC ) CREATE TABLE [dbo].[Sections]( [Id] [bigint] IDENTITY(1,1) NOT NULL, [ClassId] [bigint] NOT NULL, [InternalCode] [varchar](10) NOT NULL, CONSTRAINT [PK_Sections] PRIMARY KEY CLUSTERED ( [Id] ASC ) CREATE TABLE [dbo].[SectionStudents]( [SectionId] [bigint] NOT NULL, [UserId] [uniqueidentifier] NOT NULL, CONSTRAINT [PK_SectionStudents] PRIMARY KEY CLUSTERED ( [SectionId] ASC, [UserId] ASC ) CREATE TABLE [dbo].[aspnet_Users]( [ApplicationId] [uniqueidentifier] NOT NULL, [UserId] [uniqueidentifier] NOT NULL, [UserName] [nvarchar](256) NOT NULL, [LoweredUserName] [nvarchar](256) NOT NULL, [MobileAlias] [nvarchar](16) NULL, [IsAnonymous] [bit] NOT NULL, [LastActivityDate] [datetime] NOT NULL, PRIMARY KEY NONCLUSTERED ( [UserId] ASC ) I omitted the foreign keys for brevity, but essentially this boils down to: A Class can have many Sections. A Section can belong to only 1 Class but can have many Students. A Student (aspnet_Users) can belong to many Sections. I've setup the corresponding Model classes and Fluent NHibernate Mapping classes, all that is working fine. Here's where I'm getting stuck. I need to write a query which will return the sections a student is enrolled in based on the student's UserId and the dates of the class. Here's what I've tried so far: 1. var sections = (from s in this.Session.Linq<Sections>() where s.Class.StartDate <= DateTime.UtcNow && s.Class.EndDate > DateTime.UtcNow && s.Students.First(f => f.UserId == userId) != null select s); 2. var sections = (from s in this.Session.Linq<Sections>() where s.Class.StartDate <= DateTime.UtcNow && s.Class.EndDate > DateTime.UtcNow && s.Students.Where(w => w.UserId == userId).FirstOrDefault().Id == userId select s); Obviously, 2 above will fail miserably if there are no students matching userId for classes the current date between it's start and end dates...but I just wanted to try. The filters for the Class StartDate and EndDate work fine, but the many-to-many relation with Students is proving to be difficult. Everytime I try running the query I get an ArgumentNullException with the message: Value cannot be null. Parameter name: session I've considered going down the path of making the SectionStudents relation a Model class with a reference to Section and a reference to Student instead of a many-to-many. I'd like to avoid that if I can, and I'm not even sure it would work that way. Thanks in advance to anyone who can help. Ryan

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  • LINQ-to-SQL and SQL Compact - database file sharing problem

    - by Eye of Hell
    Hello. I'm learing LINQ-to-SQL right now and i have wrote a simple application that define SQL data: [Table( Name = "items" )] public class Item { [ Column( IsPrimaryKey = true, IsDbGenerated = true ) ] public int Id; [ Column ] public string Name; } I have launched 2 copy of application connected to the same .sdf file and tested if all database modifications in one application affects another application. But strange thing arise. If i use InsertOnSubmit() and DeleteOnSubmit() in one application, added/removed items are instantly visible in other application via 'select' LINQ queue. But if i try to modify 'Name' field in one application, it is NOT visible in other applicaton until it reconnects the database :(. The test code i use: var Items = from c in db.Items where Id == c.Id select c; foreach( var Item in Items ) { Item.Name = "new name"; break; } db.SubmitChanges(); Can anyone suggest what i'm doing wrong and why InsertOnSubmit()/DeleteOnSubmit works and SubmitChanges() don't?

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  • calculate distance with linq or subsonic C# MVC

    - by minus4
    i have this MySQL statement from a search page, the user enters there postcode and it finds the nearest stiocklist within 15 MIles of the entered postcode. SELECT * , ( ( ACOS( SIN( "+SENTLNG +" * PI( ) /180 ) * SIN( s_lat * PI( ) /180 ) + COS( " + SENTLNG +" * PI( ) /180 ) * COS( s_lat * PI( ) /180 ) * COS( ( " + SENTLANG + " - s_lng ) * PI( ) /180 ) ) *180 / PI( ) ) *60 * 1.1515 ) AS distance_miles FROM new_stockists WHERE s_lat IS NOT NULL HAVING distance_miles <15 ORDER BY distance_miles ASC LIMIT 0 , 15 but now i am using linq and subsonic and not got a clue how do do this in linq or subsonic your help would be much appreciated, please also not that i have to sent in a dynamic from address, thats the postcode mentioned at the top of the page, i do a call to google to get then lng and lat from them for the postcode given.

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  • LINQ insert to database by WCF Service from Silverlight app

    - by Rafal
    Hi I have a problem during insert to database by LINQ command in WCF Service from Silverlight application. Receiving data works fine - select works in LINQ and shows data from database(sql server 2008). When i try to insert data, the Error ocures: System.Net.WebException: The remote server returned an error: NotFound. ---> System.Net.WebException: The remote server returned an error: NotFound. at System.Net.Browser.BrowserHttpWebRequest.InternalEndGetResponse(IAsyncResult asyncResult) at System.Net.Browser.BrowserHttpWebRequest.<>c__DisplayClass5.<EndGetResponse>b__4(Object sendState) at System.Net.Browser.AsyncHelper.<>c__DisplayClass2.<BeginOnUI>b__0(Object sendState) --- End of inner exception stack trace --- at System.Net.Browser.AsyncHelper.BeginOnUI(SendOrPostCallback beginMethod, Object state) at System.Net.Browser.BrowserHttpWebRequest.EndGetResponse(IAsyncResult asyncResult) at System.ServiceModel.Channels.HttpChannelFactory.HttpRequestChannel.HttpChannelAsyncRequest.CompleteGetResponse(IAsyncResult result)} It looks the same, when i had a wrong ClientConfig/Web.config file. Please Help...I need to insert some data:)

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  • Linq to SQL EntitySet Records causing duplicate insertion

    - by Savvas Sopiadis
    In a WPF application i'm using Linq to SQL in a multi tier application. (This is an archailogy photo filing application), so every excavation has its corresponding Pictures, thus a one-to-many relationship. This relationship is correctly created by SQLMetal (which i'm using to create the POCOs). So here is the situation i 'm having trouble with: Saving changes (either of new or altered objects) is done through UnitOfWork() pattern this way: using (IUnitOfWork unitOfWork = UnitOfWork.Begin()) { //if this is a new record if (SelectedExcavation.excavation.ExcavationId == 0) { IsNewRecord = true; excavService.Add(SelectedExcavation.excavation); } //send the actual changes to the dbms unitOfWork.Commit(); } Everything works fine! BUTTTT!!! Whenever a record gets updated which has (already at least one ) corresponding Picture Record: 1) a new Excavation Record is inserted 2) the current Excavation Record gets updated 3) the previous Picture Record gets its Id changed to the newly created ExcavationId What is going on under the hood? Does Linq to SQL not handle such simple update scenarios? Thanks in advance

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  • Linq to Entities performance within ASP.NET Development Server

    - by tster
    I've been evaluating linq to entities and linq to SQL for a project. Obviously each has its own advantages and disadvantages which have been discussed plenty of times here. However, One thing I am seeing with L2E is kind of odd. Using L2S, when using the ASP.NET Development Server, the performance is a little slower for my web service calls. I'm looking at 300ms vs. 250 ms. However, when using L2E, when using ASP.NET Dev Server, the performance is awful. I'm talking 1,250 ms vs. 220 ms. I know I should probably just use local IIS for development, but I'm curious if anyone else has seen this, or knows what is causing it.

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  • Custom Expression in Linq-to-Sql Designer

    - by csharpnoob
    According to Microsoft: http://msdn.microsoft.com/de-de/library/system.data.linq.mapping.columnattribute.expression.aspx It's possible to add expression to the Linq-to-SQL Mapping. But how to configure or add them in Visual Studio in the Designer? Problem, when I add it manual to thex XYZ.designer.cs it on change it will be lost. //------------------------------------------------------------------------------ // <auto-generated> // This code was generated by a tool. // Runtime Version:2.0.50727.4927 // // Changes to this file may cause incorrect behavior and will be lost if // the code is regenerated. // </auto-generated> //------------------------------------------------------------------------------ This is generated: [Column(Name="id", Storage="_id", DbType="Int")] public System.Nullable<int> id { ... But i need something like this [Column(Name="id", Storage="_id", DbType="Int", Expression="Max(id)")] public System.Nullable<int> id { ... Thanks.

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  • Processing a property in linq to sql

    - by Mostafa
    Hi It's my first LINQ TO SQL Project , So definitely my question could be naive . Till now I used to create new property in Business Object beside of every DateTime Property , That's because i need to do some processing in my DateTime property and show it in special string format for binding to UI Controls .Like : private DateTime _insertDate; /// /// I have "InertDate" field in my Table on Database /// public DateTime InsertDate { get { return _insertDate; } set { _insertDate = value; } } // Because i need to do some processing I create a readonly string property that pass InsertDate to Utility method and return special string Date public string PInsertDate { get { return Utility.ToSpecialDate(_insertDate); } } My question is I don't know how to do it in LINQ . I did like follow but i get run time error. ToosDataContext db = new ToosDataContext(); var newslist = from p in db.News select new {p.NewsId,p.Title,tarikh =MD.Utility.ToSpecialDate( p.ReleaseDate)}; GridView1.DataSource = newslist; GridView1.DataBind();

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  • linq NullReferenceException while checking for null reference

    - by Odrade
    I have the following LINQ query: List<FileInputItem> inputList = GetInputList(); var results = from FileInputItem f in inputList where ( Path.GetDirectoryName(f.Folder).ToLower().Trim() == somePath || Path.GetDirectoryName(f.Folder).ToLower().Trim() == someOtherPath ) && f.Expression == null select f; Every time this query is executed, it generates a NullReferenceException. If I remove the condition f.Expression == null or change it to f.Expression != null, the query executes normally (giving the wrong results, of course). The relevant bits of FileInputItem look like this: [Serializable] public class FileInputItem { [XmlElement("Folder")] public string Folder { get; set; } [XmlElement("Expression")] public string Expression { get; set; } /*SNIP. Irrelevant properties */ } I'm new to LINQ to objects, so I'm probably missing something fundamental here. What's the deal?

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  • calculate distance with linq or subsonic

    - by minus4
    i have this MySQL statement from a search page, the user enters there postcode and it finds the nearest stiocklist within 15 MIles of the entered postcode. SELECT * , ( ( ACOS( SIN( "+SENTLNG +" * PI( ) /180 ) * SIN( s_lat * PI( ) /180 ) + COS( " + SENTLNG +" * PI( ) /180 ) * COS( s_lat * PI( ) /180 ) * COS( ( " + SENTLANG + " - s_lng ) * PI( ) /180 ) ) *180 / PI( ) ) *60 * 1.1515 ) AS distance_miles FROM new_stockists WHERE s_lat IS NOT NULL HAVING distance_miles <15 ORDER BY distance_miles ASC LIMIT 0 , 15 but now i am using linq and subsonic and not got a clue how do do this in linq or subsonic your help would be much appreciated, please also not that i have to sent in a dynamic from address, thats the postcode mentioned at the top of the page, i do a call to google to get then lng and lat from them for the postcode given.

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  • Using LINQ to Obtain Max of Columns for Two Dimensional Arrays

    - by Ngu Soon Hui
    Is there anyway to use LINQ to obtain the maximum of each columns for two dimensional arrays? Assume that I have the following: var arrays = new double[5,100](); I want to get the maximum of arrays[0,:], arrays[1,:] .... arrays[4,:]. How to use LINQ to do it? I could have use such method public double GetMax(double[,] arr, int rowIndex) { var colCount = arr.GetLength(1); double max = 0.0; for(int i=0; i<colCount; i++) { max=Math.Max(Math.Abs(arr[rowIndex, i]), max); } return max; } But I would prefer a more succinct ways of doing things.

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  • "Cleanly" Deploying an ASP.NET Application with LINQ to SQL Server

    - by Bob Kaufman
    In my development environment, my SQL Server is PHILIP\SQLEXPRESS. In testing, it's ANNIE, and the live environment will have a third name yet to be determined. I would have assumed that updating the following statement in web.config would have been enough: <add name="MyConnectionString"providerName="System.Data.SqlClient" connectionString="Data Source=PHILIP\SQLEXPRESS;Initial Catalog=MyDtabase;Integrated Security=True" /> When using SqlConnection, SqlCommand, SqlDataReader and friends, that's all it took. Using LINQ, it doesn't seem to work that nicely. I see the servername repeated in my .dbml file as well as in Settings.settings. After changing it in all of those places, I get it to work. However if I'm doing a few deployments per day during testing, I want to avoid this regimen. My question is: is there a programmatic solution for LINQ to SQL that will allow me to specify the connection string once, preferably in web.config, and get everybody else to refer to it?

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  • Getting "select permission denied" when using LINQ but my account is a sysadmin

    - by Wayne M
    I have a console app that's geared to be automatically ran as a Scheduled Task. I use LINQ to SQL to pull some data out of the database, format it into a CSV and email it to a client. All of a sudden I am getting the error "SELECT permission denied for table", but the account I'm using to connect to the database (specified in my app.config file) has the "sysadmin" server role (bad programmer, I know; I'll get around to changing it to a better account later but I want to make sure it works first). I can connect directly to the SQL database using that very same account and query the table in question without a problem, it only seems to be when using the LINQ code. Any idea what would be causing this?

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