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  • Linq-To-Objects group by

    - by Oskar Kjellin
    Hey, I'm building a software for timereporting I have a Dictionary<string, Dictionary<string, double>>. The key in the main dictionary is a users name and their value is a dictionary of . I have a function GetDepartment(string UserName) which returns a string with the users department. What I want is to crate a new dictionary, of the same type, that has the department as the main key and in the subdictionary a where hours is the total for that department. I have been trying to do this with linq but did not succeed. Would be very glad for some help here! EDIT: This code does exactly what I want. But I want it in LINQ Dictionary<string, Dictionary<string, double>> temphours = new Dictionary<string, Dictionary<string, double>>(); ; foreach (var user in hours) { string department = GetDepartment(user.Key); if (!temphours.ContainsKey(department)) { temphours.Add(department, new Dictionary<string, double>()); } foreach (var customerReport in user.Value) { if (!temphours[department].ContainsKey(customerReport.Key)) { temphours[department].Add(customerReport.Key, 0); } temphours[department][customerReport.Key] += customerReport.Value; } }

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  • C# Linq List Contains Similar Elements

    - by John Peters
    Hi All, I am looking for linq query to see if there exists a similar object I have an object graph as follows Cart myCart = new Cart { List<CartProduct> myCartProduct = new List<CartProduct> { CartProduct cartProduct1 = new CartProduct { List<CartProductAttribute> a = new List<CartProductAttribute> { CartProductAttribute cpa1 = new CartProductAttribute{ title="red" }, CartProductAttribute cpa2 = new CartProductAttribute{ title="small" } } } CartProduct cartProduct2 = new CartProduct { List<CartProductAttribute> d = new List<CartProductAttribute> { CartProductAttribute cpa3 = new CartProductAttribute{ title="john" }, CartProductAttribute cpa4 = new CartProductAttribute{ title="mary" } } } } } I would like to get from the Cart = a CartProduct that has the exact same CartProductAttribute title values as a CartProduct that I need to compare. No more and no less. E.G. I need to find a similar CartProduct that has a CartProductAttribute with title="red" and a cartProductAttribute with title="small" in myCart (eg 'cartProduct1' in the example) CartProduct cartProductToCompare = new CartProduct { List<CartProductAttribute> cartProductToCompareAttributes = new List<CartProductAttribute> { CartProductAttribute cpa5 = new CartProductAttribute{ title="red" }, CartProductAttribute cpa6 = new CartProductAttribute{ title="small" } } } So from object graph myCart cartProduct1 cpa1 (title=red) cpa2 (title=small) cartProduct2 cpa3 (title=john) cpa4 (title=mary) Linq query looking for cartProductToCompare cpa5 (title=red) cpa6 (title=small) Should find cartProduct1 Hope all this makes sense... Thanks

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  • Cannot update a single field using Linq to Sql

    - by KallDrexx
    I am having a hard time attempting to update a single field without having to retrieve the whole record prior to saving. For example, in my web application I have an in place editor for the Name and Description fields of an object. Once you edit either field, it sends the new field (with the object's ID value) to the web server. What I want is the webserver to take that value and ID and only update the one field. There are only two ways google tells me to do this: 1) When I get the value I want to change, the value and the ID, retrieve the record from the database, update the field in the c# object, and then send it back to the server. I don't like this method because not only does it include a completely unnecessary database read call (which includes two tables due to the way my schema is). 2) Set UpdateCheck for all the fields (but the primary keys) to UpdateCheck.Never. This doesn't work for me (I think) due to my mapping layer between the Linq to Sql and my Entity/ViewModel layer. When I convert my entity into the linq to sql db object it seems to be updating those fields regardless of the UpdateCheck setting. This might be just because of integers, since not setting an int means it is a zero (and no, I can't use int? instead). Are there any other options that I have?

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  • Help Converting T-SQL Query to LINQ Query

    - by campbelt
    I am new to LINQ, and so am struggle over some queries that I'm sure are pretty simple. In any case, I have been hiting my head against this for a while, but I'm stumped. Can anyone here help me convert this T-SQL query into a LINQ query? Once I see how it is done, I'm sure I'll have some question about the syntax: SELECT BlogTitle FROM Blogs b JOIN BlogComments bc ON b.BlogID = bc.BlogID WHERE b.Deleted = 0 AND b.Draft = 0 AND b.[Default] = 0 AND bc.Deleted = 0 GROUP BY BlogTitle ORDER BY MAX([bc].[Timestamp]) DESC Just to show that I have tried to solve this on my own, here is what I've come up with so far, though it doesn't compile, let alone work ... var iqueryable = from blog in db.Blogs join blogComment in db.BlogComments on blog.BlogID equals blogComment.BlogID where blog.Deleted == false && blog.Draft == false && blog.Default == false && blogComment.Deleted == false group blogComment by blog.BlogID into blogGroup orderby blogGroup.Max(blogComment => blogComment.Timestamp) select blogGroup;

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  • populating object collection property with Linq

    - by Benjamin Ortuzar
    I have an XML structure that has many doc nodes, and each node may have zero or more extract paragraphs (paras). <doc> <docitem>3</docitem> <docid>129826</docid> <doctitle>sample title</doctitle> <docdatetime>2009-07-03T16:59:00</docdatetime> <collectdatetime>2009-07-03T16:59:23</collectdatetime> <summary> <summarytext>sample summary</summarytext> </summary> <paras> <paraitemcount>2</paraitemcount> <para> <paraitem>1</paraitem> <paratext>sample text 1</paratext> </para> <para> <paraitem>2</paraitem> <paratext>sample text 2</paratext> </para> </paras> </doc> <doc> ... </doc> I also has some Linq code to populate some Document objects: List<Document> documentsList = (from doc in xmlDocument.Descendants("doc") select new Document { DocId = doc.Element("docid").Value, DocTitle = doc.Element("doctitle").Value, DocDateTime = DateTime.Parse(doc.Element("docdate").Value), DocSummary = doc.Element("summary").Value, DocParas = "" ///missing code to populate List<string> } ).ToList<Document>(); Is it possible add all the paras nodes into the Document.DocParas List<string> using Linq and Xpath, or should I do this task in a different way? Note: I'm using .NET C# 3.5

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  • Create System.Data.Linq.Table in Code for Testing

    - by S. DePouw
    I have an adapter class for Linq-to-Sql: public interface IAdapter : IDisposable { Table<Data.User> Activities { get; } } Data.User is an object defined by Linq-to-Sql pointing to the User table in persistence. The implementation for this is as follows: public class Adapter : IAdapter { private readonly SecretDataContext _context = new SecretDataContext(); public void Dispose() { _context.Dispose(); } public Table<Data.User> Users { get { return _context.Users; } } } This makes mocking the persistence layer easy in unit testing, as I can just return whatever collection of data I want for Users (Rhino.Mocks): Expect.Call(_adapter.Users).Return(users); The problem is that I cannot create the object 'users' since the constructors are not accessible and the class Table is sealed. One option I tried is to just make IAdapter return IEnumerable or IQueryable, but the problem there is that I then do not have access to the methods ITable provides (e.g. InsertOnSubmit()). Is there a way I can create the fake Table in the unit test scenario so that I may be a happy TDD developer?

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  • Beginner LINQ to XML inline XML error

    - by Kyle B.
    Imports System.Xml.Linq Imports System.Linq Partial Class test2 Inherits System.Web.UI.Page Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim xml As XElement = <book> <title>My Title</title> <author>Kyle</author> <publisher>WROX</publisher> </book> End Sub End Class The above code is producing the following error: Compiler Error Message: BC30201: Expression expected. Source Error: Line 8: Line 9: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Line 10: Dim xml As XElement = <book> Line 11: <title>My Title</title> Line 12: <author>Kyle</author> Source File: C:\Inetpub\wwwroot\myproject\web\test2.aspx.vb Line: 10 Why? edit: Dim xml As XElement = New XElement("book", _ New XElement("title", "My Title"), _ New XElement("author", "Kyle"), _ New XElement("publisher", "WROX") _ ) The above code works, but obviously is not as elegant as the original and I would still appreciate an explanation of why my original syntax is wrong.

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  • Dynamic SQL To Dynamic LINQ in VB.NET with MS SQL Server 2008

    - by user337501
    I dread asking this question, because with what I've read so far I understand im gonna have to cram a lotta new things into my head. In spite of all the similiar questions(and the wide variety of answers) I thought I'd ask as nothing I've read tailors to what I need specifically enough. I need to represent the following query using LINQ: DECLARE @PurchasedInventoryItemID Int = 2 DECLARE @PurchasedInventorySectionID Int = 0 DECLARE @PurchasedInventoryItem_PurchasingCategoryID Int = 3 DECLARE @PurchasedInventorySection_PurchasingCategoryID Int = 0 DECLARE @IsActive Bit = 1 DECLARE @PropertyID Int = 2 DECLARE @PropertyValue nvarchar(1000) = 'Granny Smith' --Property1, Property2, Property3 ... SELECT O.PurchasedInventoryObjectID, O.PurchasedInventoryObjectName, O.PurchasedInventoryConjunctionID, O.Summary, O.Count, O.PropertyCount, O.IsActive FROM tblPurchasedInventoryObject As O INNER JOIN tblPurchasedInventoryConjunction As C ON C.PurchasedInventoryConjunctionID = O.PurchasedInventoryConjunctionID INNER JOIN tblPurchasedInventoryItem As I ON I.PurchasedInventoryItemID = C.PurchasedInventoryItemID INNER JOIN tblPurchasedInventorySection As S ON S.PurchasedInventorySectionID = C.PurchasedInventorySectionID INNER JOIN tblPurchasedInventoryPropertyMap as M ON M.PurchasedInventoryObjectID = O.PurchasedInventoryObjectID INNER JOIN tblPropertyValue As V ON V.PropertyValueID = M.PropertyValueID WHERE I.PurchasedInventoryItemID = @PurchasedInventoryItemID AND S.PurchasedInventorySectionID = @PurchasedInventorySectionID AND I.PurchasingCategoryID = @PurchasedInventoryItem_PurchasingCategoryID AND S.PurchasingCategoryID = @PurchasedInventorySection_PurchasingCategoryID AND O.IsActive = @IsActive AND V.PropertyID = @PropertyID AND V.Value = @PropertyValue Now, I know that a query in .NET doesnt look like this, this is my test in the SQL Design Studio. Naturally VB.NET variables will be used in place of the SQL local variables. My problem is this: All of the conditions after "WHERE" are optional. In that a query might be made that uses one, some, all, or none of the conditions. V.PropertyID and V.Value can also appear any number of times. In VB.NET I can make this query easy enough by simply concatenating strings, and using a loop to append the "V.PropertyID/V.Value" conditions. I can also make a Stored Procedure in MS SQL, which is easy enough. However, I want to accomplish this using LINQ. If anyone could direct me, I would be most appreciative.

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  • Linq to SQL case sensitivity causing problems

    - by Roger Lipscombe
    I've seen this question, but that's asking for case-insensitive comparisons when the database is case-sensitive. I'm having a problem with the exact opposite. I'm using SQL Server 2005, my database collation is set to Latin1_General_CI_AS. I've got a table, "User", like this: CREATE TABLE [dbo].[User] ( [Id] [int] IDENTITY(1,1) NOT NULL, [Name] [nvarchar](max) NOT NULL, CONSTRAINT [PK_Example] PRIMARY KEY CLUSTERED ( [Id] ASC ) ) And I'm using the following code to populate it: string[] names = new[] { "Bob", "bob", "BoB" }; using (MyDataContext dataContext = new AppCompatDataContext()) { foreach (var name in names) { string s = name; if (dataContext.Users.SingleOrDefault(u => u.Name == s) == null) dataContext.Users.InsertOnSubmit(new User { Name = name }); } dataContext.SubmitChanges(); } When I run this the first time, I end up with "Bob", "bob" and "BoB" in the table. When I run it again, I get an InvalidOperationException: "Sequence contains more than one element", because the query against the database returns all 3 rows, and... SELECT * FROM [User] WHERE Name = 'bob' ... is case-insensitive. That is: when I'm inserting rows, Linq to SQL appears to use C# case-sensitive comparisons. When I query later, Linq to SQL uses SQL Server case-insensitive comparisons. I'd like the initial insert to use case-insensitive comparisons, but when I change the code as follows... if (dataContext.Users.SingleOrDefault(u => u.Name.Equals(s, StringComparison.InvariantCultureIgnoreCase) ) == null) ... I get a NotSupportedException: "Method 'Boolean Equals(System.String, System.StringComparison)' has no supported translation to SQL." Question: how do I get the initial insert to be case-insensitive or, more precisely, match the collation of the column in the database? Update: This doesn't appear to be my problem. My problem appears to be that SingleOrDefault doesn't actually look at the pending inserts at all.

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  • Databinding question: DataGridView <=> XDocument (using LINQ-to-XML)

    - by Pretzel
    Learning LINQ has been a lot of fun so far, but despite reading a couple books and a bunch of online resources on the topic, I still feel like a total n00b. Recently, I just learned that if my query returns an Anonymous type, the DataGridView I'm populating will be ReadOnly (because, apparently Anonymous types are ReadOnly.) Right now, I'm trying to figure out the easiest way to: Get a subset of data from an XML file into a DataGridView, Allow the user to edit said data, Stick the changed data back into the XML file. So far I have Steps 1 and 2 figured out: public class Container { public string Id { get; set; } public string Barcode { get; set; } public float Quantity { get; set; } } // For use with the Distinct() operator public class ContainerComparer : IEqualityComparer<Container> { public bool Equals(Container x, Container y) { return x.Id == y.Id; } public int GetHashCode(Container obj) { return obj.Id.GetHashCode(); } } var barcodes = (from src in xmldoc.Descendants("Container") where src.Descendants().Count() > 0 select new Container { Id = (string)src.Element("Id"), Barcode = (string)src.Element("Barcode"), Quantity = float.Parse((string)src.Element("Quantity").Attribute("value")) }).Distinct(new ContainerComparer()); dataGridView1.DataSource = barcodes.ToList(); This works great at getting the data I want from the XML into the DataGridView so that the user has a way to manipulate the values. Upon doing a Step-thru trace of my code, I'm finding that the changes to the values made in DataGridView are not bound to the XDocument object and as such, do not propagate back. How do we take care of Step 3? (getting the data back to the XML) Is it possible to Bind the XML directly to the DataGridView? Or do I have to write another LINQ statement to get the data from the DGV back to the XDocument? Suggstions?

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  • LINQ Normalizing data

    - by Brennan Mann
    I am using an OMS that stores up to three line items per record in the database. Below is an example of an order containing five line items. Order Header Order Detail Prod 1 Prod 2 Prod 3 Order Detail Prod 4 Prod 5 One order header record and two detail records. My goal is have a one to one relation for details records(i.e., one detail record per line item). In the past, I used an UNION ALL SQL statement to extract the data. Is there a better approcach to this problem using LINQ? Below is my first attempt at using LINQ. Any feedback, suggestions or recommendations would greatly be appreciated. For what I have read, an UNION statement can tax the process? var orderdetail = (from o in context.ORDERSUBHEADs select new { edpNo = o.EDPNOS_001, price = o.EXTPRICES_001, qty = o.ITEMQTYS_001 } ).Union(from o in context.ORDERSUBHEADs select new { edpNo = o.EDPNOS_002, price = o.EXTPRICES_002, qty = o.ITEMQTYS_002 } ).Union(from o in context.ORDERSUBHEADs select new { edpNo = o.EDPNOS_003, price = o.EXTPRICES_003, qty = o.ITEMQTYS_003 });

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  • LINQ Query to DataTable.DataSource

    - by lumberjack
    I am trying to perform a LINQ query on a DataTable and show the result in another DataTable. My source DataTable looks something like this: DataTable myDataTable = new DataTable(); myDataTable.Columns.Add("OrderID", typeof(int)); myDataTable.Columns.Add("Date", typeof(DateTime)); myDataTable.Columns.Add("UnitsPurchased", typeof(int)); The resulting DataTable looks like this when filled: Order ID Date Units Purchased 16548 10/15/09 250 17984 11/03/09 512 20349 01/11/10 213 34872 01/15/10 175 My current LINQ query looks like this: IEnumerable<DataRow> query = (from row in myDataTable.AsEnumerable() where row.UnitsPurchased > 200 select new { row.OrderID, row.Date, row.UnitsPurchased }) as IEnumerable<DataRow>; resultDataTable.DataSource = query.CopyToDataTable<DataRow>(); Every time I run this code query is null. I can see that that the as IEnumerable<DataRow> is the culprit, but it makes no since to me since DataTable.AsEnumerable() returns an IEnumerable<DataRow>. Any help would be appreciated.

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  • Dynamic Linq Property Converting to Sql

    - by Matthew Hood
    I am trying to understand dynamic linq and expression trees. Very basically trying to do an equals supplying the column and value as strings. Here is what I have so far private IQueryable<tblTest> filterTest(string column, string value) { TestDataContext db = new TestDataContext(); // The IQueryable data to query. IQueryable<tblTest> queryableData = db.tblTests.AsQueryable(); // Compose the expression tree that represents the parameter to the predicate. ParameterExpression pe = Expression.Parameter(typeof(tblTest), "item"); Expression left = Expression.Property(pe, column); Expression right = Expression.Constant(value); Expression e1 = Expression.Equal(left, right); MethodCallExpression whereCallExpression = Expression.Call( typeof(Queryable), "Where", new Type[] { queryableData.ElementType }, queryableData.Expression, Expression.Lambda<Func<tblTest, bool>>(e1, new ParameterExpression[] { pe })); // Create an executable query from the expression tree. IQueryable<tblTest> results = queryableData.Provider.CreateQuery<tblTest>(whereCallExpression); return results; } That works fine for columns in the DB. But fails for properties in my code eg public partial class tblTest { public string name_test { get { return name; } } } Giving an error cannot be that it cannot be converted into SQL. I have tried rewriting the property as a Expression<Func but with no luck, how can I convert simple properties so they can be used with linq in this dynamic way? Many Thanks

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  • List Manipulation in C# using Linq

    - by Learner
    using System; using System.Collections.Generic; using System.Linq; using System.Linq.Expressions; using System.Text; namespace ConsoleApplication1 { public class Class1 { static void Main(string[] args) { List<Car> mylist = new List<Car>(); Car car1; Car car2; Car car3; car1 = new Car() { make = "Honda", id = 1 }; car2 = new Car() { make = "toyota", id = 2 }; car3 = new Car() { make = "Honda", id = 3, color = "red" }; mylist.Add(car1); mylist.Add(car2); **////mylist.Where(p => p.id == 1).SingleOrDefault() = car3;** } } public class Car { public int id { get; set; } public string make { get; set; } public string color { get; set; } } } How can I update the list by replacing the honda car of Id 1 with honda car with Id 3 in the best way.

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  • Creating LINQ to SQL Data Models' Data Contexts with ASP.NET MVC

    - by Maxim Z.
    I'm just getting started with ASP.NET MVC, mostly by reading ScottGu's tutorial. To create my database connections, I followed the steps he outlined, which were to create a LINQ-to-SQL dbml model, add in the database tables through the Server Explorer, and finally to create a DataContext class. That last part is the part I'm stuck on. In this class, I'm trying to create methods that work around the exposed data. Following the example in the tutorial, I created this: using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace MySite.Models { public partial class MyDataContext { public List<Post> GetPosts() { return Posts.ToList(); } public Post GetPostById(int id) { return Posts.Single(p => p.ID == id); } } } As you can see, I'm trying to use my Post data table. However, it doesn't recognize the "Posts" part of my code. What am I doing wrong? I have a feeling that my problem is related to my not adding the data tables correctly, but I'm not sure. Thanks in advance.

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  • Linq join two dictionaries using a common key

    - by rboarman
    Hello, I am trying to join two Dictionary collections together based on a common lookup value. var idList = new Dictionary<int, int>(); idList.Add(1, 1); idList.Add(3, 3); idList.Add(5, 5); var lookupList = new Dictionary<int, int>(); lookupList.Add(1, 1000); lookupList.Add(2, 1001); lookupList.Add(3, 1002); lookupList.Add(4, 1003); lookupList.Add(5, 1004); lookupList.Add(6, 1005); lookupList.Add(7, 1006); // Something like this: var q = from id in idList.Keys join entry in lookupList on entry.Key equals id select entry.Value; The Linq statement above is only an example and does not compile. For each entry in the idList, pull the value from the lookupList based on matching Keys. The result should be a list of Values from lookupList (1000, 1002, 1004). What’s the easiest way to do this using Linq? Thank you, Rick

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  • Sending items in a LINQ sequence to a method that returns void

    - by generalt
    Hello all. Often while I'm dealing with LINQ sequences, I want to send each item to a method returning void, avoiding a foreach loop. However, I haven't found an elegant way to do this. Today, I wrote the following code: private StreamWriter _sw; private void streamToFile(List<ErrorEntry> errors) { if (_sw == null) { _sw = new StreamWriter(Path.Combine (Path.GetDirectoryName(_targetDatabasePath), "errors.txt")); } Func<ErrorEntry, bool> writeSelector = (e) => { _sw.WriteLine(getTabDelimititedLine(e)); return true; }; errors.Select(writeSelector); _sw.Flush(); } As you can see, I write a lambda function that just returns true, and I realize that the Select method will return a sequence of booleans- I'll just ignore that sequence. However, this seems a little bit noobish and jank. Is there any elegant way to do this? Or am I just misapplying LINQ? Thanks.

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  • Sort a List<T> using query expressions - LINQ C#

    - by Dan Yack
    I have a problem using Linq to order a structure like this : public class Person { public int ID { get; set; } public List<PersonAttribute> Attributes { get; set; } } public class PersonAttribute { public int ID { get; set; } public string Name { get; set; } public string Value { get; set; } } A person might go like this: PersonAttribute Age = new PersonAttribute { ID = 8, Name = "Age", Value = "32" }; PersonAttribute FirstName = new PersonAttribute { ID = 9, Name = "FirstName", Value = "Rebecca" }; PersonAttribute LastName = new PersonAttribute { ID = 10, Name = "LastName", Value = "Johnson" }; PersonAttribute Gender = new PersonAttribute { ID = 11, Name = "Gender", Value = "Female" }; I would like to use LINQ projection to sort a list of persons ascending by the person attribute of my choice, for example, sort on Age, or sort on FirstName. I am trying something like string mySortAttribute = "Age" PersonList.OrderBy(p => p.PersonAttribute.Find(s => s.Name == mySortAttribute).Value); But the syntax is failing me. Any clues? Thanks in advance!

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  • How do I setup Linq to SQL and WCF

    - by Jisaak
    So I'm venturing out into the world of Linq and WCF web services and I can't seem to make the magic happen. I have a VERY basic WCF web service going and I can get my old SqlConnection calls to work and return a DataSet. But I can't/don't know how to get the Linq to SQL queries to work. I'm guessing it might be a permissions problem since I need to connect to the SQL Database with a specific set of credentials but I don't know how I can test if that is the issue. I've tried using both of these connection strings and neither seem to give me a different result. <add name="GeoDataConnectionString" connectionString="Data Source=SQLSERVER;Initial Catalog=GeoData;Integrated Security=True" providerName="System.Data.SqlClient" /> <add name="GeoDataConnectionString" connectionString="Data Source=SQLSERVER;Initial Catalog=GeoData;User ID=domain\userName; Password=blahblah; Trusted_Connection=true" providerName="System.Data.SqlClient" /> Here is the function in my service that does the query and I have the interface add the [OperationContract] public string GetCity(int cityId) { GeoDataContext db = new GeoDataContext(); var city = from c in db.Cities where c.CITY_ID == 30429 select c.DESCRIPTION; return city.ToString(); } The GeoData.dbml only has one simple table in it with a list of city id's and city names. I have also changed the "Serialization Mode" on the DataContext to "Unidirectional" which from what I've read needs to be done for WCF. When I run the service I get this as the return: SELECT [t0].[DESCRIPTION] FROM [dbo].[Cities] AS [t0] WHERE [t0].[CITY_ID] = @p0 Dang, so as I'm writing this I realize that maybe my query is all messed up?

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  • Where Not In OR Except simulation of SQL in LINQ to Objects

    - by Thinking
    Suppose I have two lists that holds the list of source file names and destination file names respectively. The Sourcefilenamelist has files as 1.txt, 2.txt,3.txt, 4.txt while the Destinaitonlist has 1.txt,2.txt. I ned to write a linq query to find out which files are in SourceList that are absent in DestinationFile list. e.g. here the out put will be 3.txt and 4.txt. I have done this by a foreach statement. but now I want to do the same by using LINQ(C#). Edit: My Code is List<FileList> sourceFileNames = new List<FileList>(); sourceFileNames.Add(new FileList { fileNames = "1.txt" }); sourceFileNames.Add(new FileList { fileNames = "2.txt" }); sourceFileNames.Add(new FileList { fileNames = "3.txt" }); sourceFileNames.Add(new FileList { fileNames = "4.txt" }); List<FileList> destinationFileNames = new List<FileList>(); destinationFileNames.Add(new FileList { fileNames = "1.txt" }); destinationFileNames.Add(new FileList { fileNames = "2.txt" }); IEnumerable<FileList> except = sourceFileNames.Except(destinationFileNames); And Filelist is a simple class with only one property fileNames of type string.

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  • Linq to sql Repository pattern , Some doubts

    - by MindlessProgrammer
    I am using repository pattern with linq to sql, I am using a repository class per table. I want to know , am i doing at good/standard way, ContactRepository Contact GetByID() Contact GetAll() COntactTagRepository List<ContactTag> Get(long contactID) List<ContactTag> GetAll() List<ContactTagDetail> GetAllDetails() class ContactTagDetail { public Contact Contact {get;set;} public ContactTag COntactTag {get;set;} } When i need a contact i call method in contactrepository, same for contacttag but when i need contact and tags together i call GetDetais() in ContactTag repository its not returning the COntactTag entity generated by the orm insted its returning ContactTagDetail entity conatining both COntact and COntactTag generated by the orm, i know i can simple call GetAll in COntactTag repository and can access Contact.ContactTag but as its linq to sql it will there is no option to Deferred Load in query level, so whenever i need a entity with a related entity i create a projection class Another doubt is where i really need to right the method i can do it in both contact & ContactTag repostitory like In contact repository GetALlWithTags() or something but i am doing it in in COntactTag repository Whats your suggestions ?

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  • Custom Detail in Linq-to-SQL Master-Detail DataGridViews

    - by Andres
    Hi, looking for a way to create Linq-to-SQL Master-Detail WinForms DataGridViews where the Detail part of the Linq query is a custom one. Can do fine this: DataClasses1DataContext db = new DataClasses1DataContext(".\\SQLExpress"); var myQuery = from o in db.Orders select o; dataGridView1.DataSource = new BindingSource() { DataSource = myQuery }; dataGridView2.DataSource = new BindingSource() { DataSource = dataGridView1.DataSource, DataMember = "OrderDetails" }; but I'd like to have the Detail part under my precise control, like var myQuery = from o in db.Orders join od in db.OrderDetails on o.ID equals od.OrderID into MyOwnSubQuery select o; and use it for the second grid: dataGridView2.DataSource = new BindingSource() { DataSource = dataGridView1.DataSource, DataMember = "MyOwnSubQuery" // not working... }; the real reason I want it is a bit more complex (I'd like to have the Detail part to be some not-pre-defined join actually), but I'm hoping the above conveyed the idea. Can I only have the Detail part as a plain sub-table coming out of the pre-defined relation or can I do more complex stuff with the Detail part? Does anyone else feel this is kind of limited (if the first example is the best we can do)? Thanks!

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  • DataReader already open when using LINQ

    - by Jamie Dixon
    I've got a static class containing a static field which makes reference to a wrapper object of a DataContext. The DataContext is basically generated by Visual Studio when we created a dbml file & contains methods for each of the stored procedures we have in the DB. Our class basically has a bunch of static methods that fire off each of these stored proc methods & then returns an array based on a LINQ query. Example: public static TwoFieldBarData[] GetAgesReportData(string pct) { return DataContext .BreakdownOfUsersByAge(Constants.USER_MEDICAL_PROFILE_KEY, pct) .Select(x => new TwoFieldBarData(x.DisplayName, x.LeftValue, x.RightValue, x.TotalCount)) .ToArray(); } Every now and then, we get the following error: There is already an open DataReader associated with this Command which must be closed firs This is happening intermittently and I'm curious as to what is going on. My guess is that when there's some lag between one method executing and the next one firing, it's locking up the DataContext and throwing the error. Could this be a case for wrapping each of the DataContext LINQ calls in a lock(){} to obtain exclusivity to that type and ensure other requests are queued?

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  • Using LINQ on observable with GroupBy and Sum aggregate

    - by Mark Oates
    I have the following block of code which works fine; var boughtItemsToday = (from DBControl.MoneySpent bought in BoughtItemDB.BoughtItems select bought); BoughtItems = new ObservableCollection<DBControl.MoneySpent>(boughtItemsToday); It returns data from my MoneySpent table which includes ItemCategory, ItemAmount, ItemDateTime. I want to change it to group by ItemCategory and ItemAmount so I can see where I am spending most of my money, so I created a GroupBy query, and ended up with this; var finalQuery = boughtItemsToday.AsQueryable().GroupBy(category => category.ItemCategory); BoughtItems = new ObservableCollection<DBControl.MoneySpent>(finalQuery); Which gives me 2 errors; Error 1 The best overloaded method match for 'System.Collections.ObjectModel.ObservableCollection.ObservableCollection(System.Collections.Generic.List)' has some invalid arguments Error 2 Argument 1: cannot convert from 'System.Linq.IQueryable' to 'System.Collections.Generic.List' And this is where I'm stuck! How can I use the GroupBy and Sum aggregate function to get a list of my categories and the associated spend in 1 LINQ query?! Any help/suggestions gratefully received. Mark

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  • Silverlight - C# and LINQ - Ordering By Multiple Fields

    - by user70192
    Hello, I have an ObservableCollection of Task objects. Each Task has the following properties: AssignedTo Category Title AssignedDate I'm giving the user an interface to select which of these fields they was to sort by. In some cases, a user may want to sort by up to three of these properties. How do I dynamically build a LINQ statement that will allow me to sort by the selected fields in either ascending or descending order? Currently, I'm trying the following, but it appears to only sort by the last sort applied: var sortedTasks = from task in tasks select task; if (userWantsToSortByAssignedTo == true) { if (sortByAssignedToDescending == true) sortedTasks = sortedTasks.OrderByDescending(t => t.AssignedTo); else sortedTasks = sortedTasks.OrderBy(t => t.AssignedTo); } if (userWantsToSortByCategory == true) { if (sortByCategoryDescending == true) sortedTasks = sortedTasks.OrderByDescending(t => t.Category); else sortedTasks = sortedTasks.OrderBy(t => t.Category); } Is there an elegant way to dynamicaly append order clauses to a LINQ statement?

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