LINQ in Action - THE LINQ book

October 2008 - Posts

• How do you filter a Collection using linq

  Hi, Let's suppose i want to filter from a list the surname "Gates and Smith,how do you do it? Am I missing the obvious Code Snippet class Program { static void Main( string [] args) { List Customer > customerList = new List Customer >(); customerList.Add( new Customer { Id=1,Name= "Jo" ,Surname= "Bloggs" }); customerList.Add( new Customer { Id = 2, Name = "Mark" , Surname = "Smith" }); customerList.Add( new Customer { Id = 3, Name = "Howard" , Surname = "Gates" }); customerList.Add( new Customer Read More... Posted Friday, October 31, 2008 9:18 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Cannot seem to Filter an array of PropertyInfo[] using Linq

  I am trying to get a list of properties and I want to exclude (3 Properties "IsSavable,GetBrokenRules,IsValid") But the following does not work. Is my query Wrong. How do you write a query and filter stuff? Code Snippet PropertyInfo []propertyList = GetPropertyList(customerClassType); private PropertyInfo [] GetPropertyList( Type t) { Cursor csr = null ; csr = this .Cursor; this .Cursor = Cursors .WaitCursor; PropertyInfo [] propList = .GetPropertiesByType(t).Where(p=>p.Name!= "IsSavable" | p.Name!= Read More... Posted Friday, October 31, 2008 9:18 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Missing records in LINQ with typed dataset

  Hello MSDN experts, I'm trialling VB 2008 express edition. My code doesn't work with a typed dataset. Code Block Sub Main() Dim ds As UKAdvDataSet = New UKAdvDataSet() Dim dload = ds.dl Dim query = _ From o In dload _ Select New With {.Stage = o.Stage} For Each o In query Console.WriteLine(o.Stage.ToString) Next Console.ReadLine() End Sub UKAdv.mdf is not in "Data Sources". UKAdv.mdf is in an SQL Express Advanced sub-folder of C:\Program Files\Microsoft SQL Server\ When I run the code there are no Read More... Posted Friday, October 31, 2008 7:41 PM from MSDN Forums: LINQ Project General | (Comments Off)

• I am working on linq with store procedure with web service.

  Hi All, I am working on webservice with ling + store procedure. i dont know the exact way of implementing all these threee webservice+linq+store procedure I tried many ways to implement nothing worked out as i expected. What i need to do is i need to create a web service [webMethod] where it has store procedure with parameters?. And i need another web service[WebMethod]which has typed dataset and i need to fill values from database and show that inside a grid or any other control which are bindable. Read More... Posted Friday, October 31, 2008 5:07 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Cancel last made changes into database using LINQ

  Hi Guys, I am working on Cms site and at present working on dynamic adding of controls to the page. For adding the control i am using a rad window which displays a list of available controls and user can select as many controls as he wants and those controls should be added to the page. Now there are 2 pages. 1) Main page where controls will be added. 2) A rad window page which acts as a container of controls for user to add on the page. On rad window when the user select any controls the records Read More... Posted Friday, October 31, 2008 5:02 AM from MSDN Forums: LINQ Project General | (Comments Off)

• pass a variable into a linq query

  I'm using: Visual Web Developer 2008 SQL Server Express 2008 C# codebehind Question: How do I pass a variable into a linq query? Situation: I'm trying to use the value of a Label inside of a GridView's row during it's "RowDataBound" event in a linq query. Code Snippet Label l1 = (Label)e.Row.Cells[1].FindControl("lbl"); string l2 = l1.ToString(); aDataContext db = new aDataContext(); var q = from a in db.tblOne where a.p1 == l2 select a.p2; Label1.Text = custLastName.ToString(); *l2 is the variable Read More... Posted Friday, October 31, 2008 2:34 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Linq to XML query condition

  Hello, I am new to Linq. I have this xml file that I want to query: NO NO NO NO YES YES Yes Yes Yes Yes Yes Yes NO NO NO NO YES YES Yes Yes Yes Yes YES YES And here is my linq code: string aPath = AppDomain.CurrentDomain.BaseDirectory; aPath = aPath + "\\AppConfig.xml"; XDocument configFile = XDocument.Load(aPath); var setup = from UserElement in configFile.Descendants("USER") where UserElement.Attributes().Count()>0 && UserElement.Attribute("CODE") != null && UserElement.Attribute("CODE").Value.Equals("2") Read More... Posted Thursday, October 30, 2008 11:22 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Map linq entity field to sql function instead of column

  Can i map a linq entity field to a sql function ? i want to use entity field like computed column in sql.Instead of directly populating from a table column, can't we call UDF to populate this and pass another table column as a parameter to the function ? Read More... Posted Thursday, October 30, 2008 10:27 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Open XML SDK at TechEd EMEA Developers

  I’ll be presenting two sessions on the Open XML SDK at Tech Ed 2008 EMEA in Barcelona. OFC206 - Open XML SDK Version 2 Overview and Architecture (November 12, 13:30 - 14:45) In this session, I’ll present an overview of V2 of the Open XML SDK. I’ll talk a bit about the architecture of the Open XML formats. I’ll then compare and contrast the Office object model and the Open XML SDK, and the key benefits from using the SDK. We’ll discuss the architecture of the Open XML SDK, and the roadmap for the Read More... Posted Thursday, October 30, 2008 9:59 PM from Eric White's Blog | (Comments Off) Filed under: LINQ, OpenXML, LINQ to XML, OpenXmlSdk, Functional Programming, TechEd2008

• Demo Files for the Open XML SDK Session at PDC

  Zeyad presented this morning on the Open XML SDK at PDC. You can view the video of the talk here – it’s on day four, titled Open XML Format SDK: Developing Open XML Solutions. (The video will be available sometime on 10/31/2008). The demos for that talk are attached as a zip file to this post. Some of these demos use the Adventure Works database. You can download that database here . This blog post provides my checklist for getting going with LINQ to SQL quickly. Great job on the talk, Zeyad! J Read More... Posted Thursday, October 30, 2008 9:42 PM from Eric White's Blog | (Comments Off) Filed under: OpenXML, OpenXmlSdk, PDC2008

• Linq to XML in visual basic

  I'm wondering if its legal to add a static regex statement in the select statement of a linq query. Also is there an example and what the syntax for doing it? To strip tags from HTML and return just a portion of the tag to my Generic.IEnumerable(Of String) list. Dim links = From link In Mytabledata... _ Where InStr(link.@href, "[AC35]") > 0 _ Select ( get text between "code =" and "&" in a regex static statement from link.value) I could only find a couple of examples of comparing matches. None of Read More... Posted Thursday, October 30, 2008 5:52 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Group Join in VB.Net, can't use boolean for joinCondition

  hi, i'm trying to write a query to do a group join, but the join condition is NOT simple equality: it's the result of a function, which SQL Server supports, but VB is requiring the Equals keyword and to refer one of the values from each side of the join. Can anyone tell me another way to do this? btw, i'm sure i don't have the rest of the syntax right yet. Dim originalcodeview = From activebranch In Me.ActiveBranches _ Group Join chng In Changes _ On VersionControlPath.IsSubItem(chng.GetCurrentNamespaceForBranchSource, Read More... Posted Thursday, October 30, 2008 2:46 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Filter associated entities

  Hi, I have three tables ( or entities) like, Order (OrderId,OrderNo) OrderDetails(OrderDetailId,OrderId,ItemId,Qty,OrderType) Item(ItemId,ItemName,Price) Order and OrderDetails are linked using OrderId.OrderDetails and Item are linked using ItemId(but depends on OrderType.i.e. If OrderType = 1, then i store ItemId else I store id of a different table). So in Map file there is no association between Orderdetails and Item. I want to fetch a details of a particular oder. In linq , it will automatically Read More... Posted Thursday, October 30, 2008 1:38 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Enable Sorting not working for manually added columns

  Hello, Is there a reason the checkbox "Enable Sorting" for a GridView, does not apply to columns you created? I have a linqdatasource that retrieves Orders from northwind. I created a new column to display a hyperlink that will redirect the user to another page displaying the orderdetails. However, the column header is not 'sortable', but the other columns is. What am I doing wrong? Do I have to write a custom sort expression perhaps? Thanks! Read More... Posted Thursday, October 30, 2008 12:53 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Adding row to Table<> and using it before inserting in database

  Hi Guys, I have few doubts..Please do help me out My prob is: 1) I want few records in Table based on crtiteria but its not working... here is my code: Code Snippet Table objConrtolTable = obProductsFacade.GetTableByID(objProducts.ID) as Table; The obProductsFacade.GetTableByID has this code: Code Snippet var result = from product in objLinqObjectDataContext.Products where (product.ID == _id) select product; return result; I want few records and put it into the table object and then insert records Read More... Posted Wednesday, October 29, 2008 10:02 PM from MSDN Forums: LINQ Project General | (Comments Off)

• String issue in Linq WHERE clause

  Code Snippet protected void populateAttributeList(int VersionID, int ProductID, ListBox lb, string AttType) { lb.Items.Clear(); DAL.myDataContext db = new DAL.myDataContext(); var AttributeValues = from a in db.ProductMasterAttributes where a.ProductID == ProductID select a; if (AttType.Length > 0) AttributeValues = AttributeValues.Where(p => p.AttributeValue.Attribute.AttributeType.DisplayName == AttType); ... Wow - this is a wierd one. I wanted to pass into my method "AttType" which is a string Read More... Posted Wednesday, October 29, 2008 9:59 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Linq To Xsd DataContract

  Generating classes from Xsd files using Linq To Xsd is great. However, I would like to know if it is possible to somehow specify in the Xsd that attributes be applied to classes and their properties. To be specific, I am looking for a way to have Linq To Xsd generate classes with a System.Runtime.Serialization.DataContractAttribute applied and properties with the System.Runtime.Serialization.DataMemberAttribute applied. Something similar to the following... [System.Runtime.Serialization.DataContract] Read More... Posted Wednesday, October 29, 2008 7:44 PM from MSDN Forums: LINQ Project General | (Comments Off)

• LINQ - better way to work.

  Hi, We have some projects in .NET Framework 2.0 and, now, new projects will develop in .NET 3.5. I thinked in this architeture: - Create one table-valued function for each Table in Database; - Create custom classes (DTO) and Inherits Results (from Table-valued) classes. Why? Lets supose I have 2 tables: Orders and Products. My DTO Orders Class will have a Generic List of Products (DTO). I tried develop a protype but I dont know the better way to do a single select to fill DTO Orders and DTO Products. Read More... Posted Wednesday, October 29, 2008 6:45 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Anders Hejlsberg Introduces C# 4.0 at PDC 2008

  [Blog Map] Anders Hejlsberg presented a fascinating and entertaining session at PDC 2008 on C# 4.0 . He talked about dynamic typing, optional and named parameters, improved COM interoperability, and improved support for co-variance and contra-variance. These language improvements are very cool – they enable us to write code that more closely expresses our intent, with less syntactic noise. Carve out some time, and watch his PDC session . Anders is a dynamic presenter, so you won’t be bored! Dynamic Read More... Posted Wednesday, October 29, 2008 9:41 AM from Eric White's Blog | (Comments Off) Filed under: LINQ, OpenXML, LINQ to XML, PDC2008, Functional Programming, Dynamic Types

• Need help translating C# Linq to VB.Net

  Hello all, Can anyone help me translate this C# Linq code into VB.Net? Thanks! var orig = dsOriginal.Tables[ 0 ].AsEnumerable(); var updated = dsChanged.Tables[ 0 ].AsEnumerable(); // First, getting new records if any var newRec = from u in dsChanged where !(from o in orig select o.Field( " PRIMARY_KEY_FIELD" )) .Contains(u.Field( " PRIMARY_KEY_FIELD" )) select new { prim_key = u.Field( " PRIMARY_KEY_FIELD" ), field1 = u.Field( " FIELD1" ), field2=u.Field( " FIELD2" ), field3 = u.Field( " FIELD3" Read More... Posted Tuesday, October 28, 2008 11:19 PM from MSDN Forums: LINQ Project General | (Comments Off)

• LINQ: Group By and aggregated queries over multiple columns - VB.NET

  Hi,I have a fairly simple sql query that I want to convert to LINQ using VB.NET: SELECT WorkTab.tResult, MAX(WorkTabStatus.sCode) AS s1 FROM WorkTab INNER JOIN WorkTabStatus ON WorkTab.InstrumentID = WorkTabStatus.InstrumentID AND WorkTab.wListnr = WorkTabStatus.wListNr AND WorkTab.Seq = WorkTabStatus.Seq AND WorkTab.Anr = WorkTabStatus.Anr GROUP BY WorkTab.tResult, WorkTab.wListnr HAVING (WorkTab.wListnr = 270) I've been searching around trying to find examples of similar queries, but many of the Read More... Posted Tuesday, October 28, 2008 8:56 PM from MSDN Forums: LINQ Project General | (Comments Off)

• DataContext.ExecuteQuery<T>

  This one has me completely confused. I am developing a search form for my application and I am dynamically creating queries based on the users input and then executing them via DataContext.ExecuteQuery but some weird things happen when I try and do INNER JOINs. Code Snippet string query = "SELECT * FROM Unit INNER JOIN UnitType ON UnitType.Id = Unit.UnitTypeId WHERE UnitType.Amenities LIKE '%Balcony%'"; IEnumerable units = PropertyDatabase.ExecuteQuery(query); If I run the above code I get a list Read More... Posted Tuesday, October 28, 2008 4:37 AM from MSDN Forums: LINQ Project General | (Comments Off)

• An object equivalent to .AsDataView()

  Hello, I think the AsDataView() method of LINQ to DataSet is very useful. It provides an editable/filtrable/sortable "LINQ view" of a collection. The view is expressed as a LINQ query. If I modify the original collection the changes are reflected automatically in the view, including filters and order considerations. Very nice! Is it posible the same kind of "LINQ view" with LINQ to Objects? Thanks! Read More... Posted Tuesday, October 28, 2008 3:41 AM from MSDN Forums: LINQ Project General | (Comments Off)

• LINQ - Distinct operator on Projections

  Hi, Trying something like dim lst = From c in SomeCollectionWithDuplicates _ Select New CustomerInfo with {.ID = c.CustomerID, .Name = c.CompanyName} _ Distinct The problem is that I get duplicates. I overrode Equals on CustomerInfo but it doesn't seem to work. How do I do it? Thanks, Cosmin Read More... Posted Tuesday, October 28, 2008 2:35 AM from MSDN Forums: LINQ Project General | (Comments Off)

• LINQ and SQLite

  Hello Everyone, I am currently investigating LINQ technology on how useful it is and its maturity. Does anyone could tell me how useful LINQ is? Another concern I have is I am using SQLite Database. And LINQ to SQL only support SQL Server. Am I the right track using LINQ to Dataset to query SQLite DB? Coz what I am doing right now is transferring xml data into sqlite database. Is there anyway where I can map xml schema to database schema using LINQ? How am I going to create classes in LINQ to Dataset Read More... Posted Tuesday, October 28, 2008 1:46 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Could these be combined to one statement?

  Could this be combined to one LINQ statement? private string GetUserNameByID( string id) { Guid guid = new Guid (id); UICDataContext db = new UICDataContext (); IEnumerable aspnet_Application > query = from app in db.aspnet_Applications where app.ApplicationName == Request.ApplicationPath select app; aspnet_Application temp = query.First aspnet_Application >(); IEnumerable aspnet_User > query2 = from users in db.aspnet_Users where users.UserId == guid && users.ApplicationId == temp.ApplicationId Read More... Posted Tuesday, October 28, 2008 1:12 AM from MSDN Forums: LINQ Project General | (Comments Off)

• LINQ to SQL set foreign key to null

  Here my code: if (db.PressArticles.Count(pa => pa.Image.width == 255 && pa.ID == ArticleID) > 0) { PressArticle thisArticle = db.PressArticles.Where(pa => pa.Image.width == 255 && pa.ID == ArticleID).First(); Image delImage = db.Images.Where(i => i.ID == thisArticle.imageID).First(); db.Images.DeleteOnSubmit(delImage); db.SubmitChanges(); thisArticle.imageID = null; db.SubmitChanges(); } In my DBML file I have the following: PressArticle Image ID(Primary key) ID(Primary key) heading alt synopsis Read More... Posted Tuesday, October 28, 2008 12:34 AM from MSDN Forums: LINQ Project General | (Comments Off)

• How to get the name of the parent of an embedded node

  I have the following xml and am trying to get the name of the outer parent for the "element" nodes by using Linq. Notice that the "element" nodes are at different levels in each grouping: http://www.w3.org/2001/XMLSchema " version="1.0"> I tried the followwing without success: XNamespace aw = "http://www.w3.org/2001/XMLSchema" ; IEnumerable XElement > ele = from el in doc.Descendants(aw + "element" ) select el; foreach ( XElement keyword in ele) { XElement parent = ( XElement )keyword.Ancestors().First(); Read More... Posted Monday, October 27, 2008 9:45 PM from MSDN Forums: LINQ Project General | (Comments Off)

• LINQ To SQL ORM and Default Values

  Hi All, I am using the LINQ to SQL ORM to help tidy up the middler tier in our application. I have a form with 'create new' feature, and when the user creates a new entity, I want that that entities default values to be already selected on the form. So far, common development requirement I thought. Now I can set the default's at the database-level (SQL Server), but these do not by default have any impact on LINQ To SQL in the ORM. Jumping ahead a bit here my question does closely relate to an item Read More... Posted Monday, October 27, 2008 5:55 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Using an XML Literal to build a Document

  Dim contact1 As XElement = _ Patrick Hines "home" >%% "work" > " >%% Function1 End Function1 Function2 End Function2 I want to use an XML literal to define the structure for an XML document that I want to generate. What I don't see is how to loop thru a literal and incrementally build an XML document.. So if I wanted to produce an xml document with a thousand instances of the contact1 format, how would that look. thanks, Fred Read More... Posted Monday, October 27, 2008 3:58 AM from MSDN Forums: LINQ Project General | (Comments Off)

• How to sort list of objects?

  Hi, I'm trying to sort a list of objects: using System; using System.Collections.Generic; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Linq; using System.Linq.Expressions; public partial class test : System.Web.UI. Page { protected void Page_Load( object sender, EventArgs e) { string field = Request.Params[ "f" ].ToString(); List Data > data = GenerateItems(20); var param = Expression .Parameter( typeof ( Data ), "item" ); var sort = Expression .Lambda Func Read More... Posted Monday, October 27, 2008 12:13 AM from MSDN Forums: LINQ Project General | (Comments Off)

• How to Use altChunk for Document Assembly

  [Blog Map] Merging multiple word processing documents into a single document is something that many people want to do. An application built for attorneys might assemble selected standard clauses into a contract. An application built for book publishers can assemble chapters of a book into a single document. This post explains the semantics of the altChunk element, and provides some code using the Open XML SDK that shows how to use altChunk. Instead of using altChunk, you could write a program to Read More... Posted Sunday, October 26, 2008 10:45 PM from Eric White's Blog | (Comments Off) Filed under: OpenXML, LINQ to XML, OpenXmlSdk

• How save LINQ records to database if IList(Of Employee) contains existing and new records?

  I have a collection of employees: Protected employees As IList(Of Employee) In it, I have added some employee records from the database (and then modified). And some employee records are brand new. To persists my inserts and updates to the database, I assume I can't just call dc.SubmitChanges() or can I? I was thinking I'd need to iterate through the collection and detect if is a new or existing records and call InsertOnSubmit if it's new?... For Each employee As Employees In employees dc.LotPens.InsertOnSubmit(employee) Read More... Posted Sunday, October 26, 2008 10:33 PM from MSDN Forums: LINQ Project General | (Comments Off)

• I'm the first ever to see "1 of 2 updates failed" error?!?!

  I'm Googling for this error and get nothing. I searched the forum here and get nothing. Am I the first to ever see this LINQ error? It happens on the SubmitChanges line. I can't even step into (F11) the SubmitChanges code, it errors and won't go in. I have no idea what this means, but I'm not really a LINQ expert yet. Can anyone shed some light on this error? I'm obviously stumped. Read More... Posted Sunday, October 26, 2008 9:45 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Selecting from generic.list where item has certain pattern

  Hi Guys, I am looping through a list and want to get my car name. This test query I have written* just select the item that contains "Car Name=" but I actually need the name after the = symbol and between the " the item might look like this: "Car Name="mycar" CarType="4x4" I am quite new to linq and would like to know if the syntax can do something like this. * Dim query = From ListItem As String In DimenionsAndMemberList(i) _ Where ListItem.Contains("Car Name=") = True _ Select ListItem moveableLabel.Text Read More... Posted Sunday, October 26, 2008 9:00 PM from MSDN Forums: LINQ Project General | (Comments Off)

• generating dbml file very slow

  My database has ~350 tables. It's taking a very long time to complete - it's been runing for 20minutes. Any ideas on how to speed up this process or what could be wrong? Read More... Posted Sunday, October 26, 2008 7:02 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Use Linqs Auto-Sync in combination with reflections

  Hi, I like the auto-sync possibilities when i have an EntityTable and EntityDetailsTable with auto generated identities. For example: Car: ID identity type CarDetails: ID LanguageCode Description Now i can store language independent content in the Car table and language dependent content in the CarDetails. With auto-sync it was always assured that the ID in Car and ID in CarDetails were the same. Let's have a look at the following code: car1.ID = 1; car1.type = "type1"; DataContext.InsertOnSubmit(car1); Read More... Posted Sunday, October 26, 2008 6:24 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Display data using LINQ

  Hi all, Have a question regarding the use of LINQ. First let me explain the scenario: I have a database with 5 fields: CustomerID, CustomerName, CustomerAddress, CustomerAge and CustomerCountry. I created a query using LINQ in order to get only CustomerID and CustomerName in a datagridview control. Also I have a cmdbtn called "Display Rest of Info". What I would like to get is display the rest of the fields (CAddress,CAge and CCountry) by selecting a specific row and clicking the cmdbtn. Do you have Read More... Posted Friday, October 24, 2008 6:26 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Linq editing data tables

  Hi, I'm extremely new to LINQ and don't really know what it's capable of doing. We would like to use LINQ as a datasource for a grid we have but we need to link to more than one table so we can edit data. Is it possible to create a dataset that contains multiple sql tables then use LINQ to query and edit the infromation in those tables? I might be way out to lunch on this but I have to ask. thanks! Read More... Posted Friday, October 24, 2008 1:37 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Wrrrrrrrr .............. user rights to update ???????

  I try to update some records in my ERP-system with a small C#program using the LINQ-technic. The code executes without errors and by stepping I can see the values are updateted as exspected, but when I look at the data in the ERP-system ... no update has taken place ! If I have no updating rights I think I should get some error message from my C# code - right ? I have tried to run the view I'm using as the datacontext in the LINQ - run it in the IDE - and directly in the shown table update to the Read More... Posted Friday, October 24, 2008 1:19 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Connection Status after DataBind() to IQueryable variable

  Hey Everyone! I'm falling more in love with LINQ the more I use it. I've had no problem figuring out the code, but I have a question about how the connection object is handled once the following two methods complete. On my ASPX, I have a gridview that is just displaying data. I have a method to bind, and a Data Access Layer method to retrieve the data. Here's the code: Code Snippet /// /// Binds the gridview to most recent float entry data /// private void GetLatestFloatDataForGrid() { gvFloatData.DataSource Read More... Posted Friday, October 24, 2008 12:53 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Qureting Multiple Tables and intersecting

  Hi , I am new to Linq. I want to intersect two tables . one table WebPages contains ('Url','Title','LastUpdated') & other table DupWebPages contains ('url') columns respectively. I want to extract all rows from tbale WebPages which are such that WebPages.Url is not in {DupWebPages.Url} how can I use multiple tables to intersect two sents on the bases of Url column. Regards Pankaj Read More... Posted Thursday, October 23, 2008 9:54 PM from MSDN Forums: LINQ Project General | (Comments Off)

• [Help] XML attribute parse

  test.xml Sliverlight C# Code: XmlReader reader = XmlReader.Create(new StringReader(e.Result)); XDocument document = XDocument.Load(reader); var q = from p in document.Element("Configuration").Elements() select p; foreach (var _e in q) { tbInfo.Text ="AA:" +_e.Element("F2").Attribute("value") ; } I tried to get the q info while debugging. the content of q is " ". But when it run to line (string)ed.Element(" F2 ").Attribute("value").Value, it threw an error "System.NullReferenceException: Object reference Read More... Posted Thursday, October 23, 2008 9:52 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Great Hardware for SharePoint Development

  I have a couple of nice computers that I use for SharePoint development. In this post, I’m going to share the configuration of my setup. This isn’t to say that this is the only good way to set up hardware for SharePoint development. However, my machines are pretty good. If these computers were very expensive, and I could only have them because Microsoft bought them, then I’d feel bad (well, at least a little bit J ), and wouldn’t tell you about them. However, they are not expensive – they’re reasonably Read More... Posted Thursday, October 23, 2008 7:30 PM from Eric White's Blog | (Comments Off) Filed under: SharePoint

• Bug in Linq compiled queries?

  I've read that compiled queries are faster, so I've tried to use this. Inexplicably the following code throws this exception: System.InvalidCastException: Unable to cast object of type 'OneTimeEnumerable`1[SupportToolServices+GetReferrersResult]' to type 'GetReferrersResult[]'. at System.Data.Linq.CompiledQuery.Invoke[TArg0,TArg1,TArg2,TResult](TArg0 arg0, TArg1 arg1, TArg2 arg2) at SupportToolServices.GetReferrers(DateTime start, DateTime end) in ... when I use a compiled query. If I comment out Read More... Posted Thursday, October 23, 2008 6:29 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Convert DataTable to IList<SomeType> using LINQ

  Hi, is it possible to convert a DataTable to a generic IList (IList) using LINQ? I could write my own function use Reflection to solve this but I am looking for some builtin solution. Thanks in advance. Thanks Tanvir. Read More... Posted Thursday, October 23, 2008 6:25 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Comparing LINQ to XML and XPath

  I was in a meeting this afternoon, and someone said that they wished that there was a comparison of XPath expressions and LINQ to XML queries. Well, this already exists in the LINQ to XML document. The topic title is LINQ to XML for XPath Users . If you already speak XPath, this can provide a head-start on learning how to write LINQ to XML queries. Read More... Posted Thursday, October 23, 2008 5:59 PM from Eric White's Blog | (Comments Off) Filed under: xml, LINQ to XML

• LINQ to SQL: Associations won't serialize properly

  Hi everybody. I'm having really a hard time here trying to figure out this problem. Let's take the classic sample example or these two classes: Customer - [Guid] CustomerId - [String] Name Order - [Guid] OrderId - [Guid] CustomerId - [String] Name I have them on my LINQ to SQL Data Context. So far, so good. Everything work as a charm. But the problem is that this DataContext lives in a WCF Service and I have to serialize asd these classes in order to make them be used on my clients. Alright, I just Read More... Posted Thursday, October 23, 2008 5:07 AM from MSDN Forums: LINQ Project General | (Comments Off)

• error: "Types in Union or Concat cannot be constructed with hierarchy"

  Anybody seen this error? "System.NotSupportedException: Types in Union or Concat cannot be constructed with hierarchy." Error thrown on the last line of code below. Here's what I was trying to do... var query = from serviceTicket in db.ServiceTickets join serviceRecord in db.ServiceRecords on serviceTicket equals serviceRecord.ServiceTicket into serviceTicketServiceRecords from serviceRecord in serviceTicketServiceRecords select new { SN = serviceTicket.Equipment.SN, JCN = serviceTicket.JCN, JCNStartDate Read More... Posted Thursday, October 23, 2008 1:35 AM from MSDN Forums: LINQ Project General | (Comments Off)

• access data in code from LINQ to SQL query

  Below is my query that works fine in getting the record I need and I am able to bind it to a control to display the data in my ASP.NET program. However, I don't want to bind it to a control for display but I want to access the data in the query with code by putting it into variables which will then be put it into a memory stream to be sent by email. I send data thru a memorystream by email in another part of the program but pull the data directly from the form. That works fine. But in this second Read More... Posted Wednesday, October 22, 2008 8:50 PM from MSDN Forums: LINQ Project General | (Comments Off)

• LINQ Average

  Hi All, I'm wondering whether its possible to do the following: I have ignore all the general rules to make thing easily. public class Data{ public int A; public int B; public int C; Status DataStatus; } public enum DataStatus{ Valid, Invalid } If I have a ICollection of Data, blockData is it possible to have: // DataStatus must be valid? public Data AverageDayData{ return blockData.Average( ???? ); } instead of public Data AverageDayData{ Data newData = new Data(); newData.A = blockData.Average( Read More... Posted Wednesday, October 22, 2008 8:44 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Default Value Updation with LINQ

  I found that the if you have a default value for a column in DB, LINQ does not update them automatically. The solution I found on the forums is to set the following properties on the DBML classes for each column. Auto-GeneratedValue = True Auto-Sync = OnInsert/OnUpdate (accordingly) So now here I havea table with these 2 columns. - InsertedOn - DateTime - Auto-Sync : OnInsert - UpdatedOn - DateTime - Auto-Sync : OnUpdate I have set the default value on them as : getdate() I set the above properties Read More... Posted Wednesday, October 22, 2008 8:18 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Writing for Professional Developers

  [Blog Map] If you are a writer, there is no substitute for making writing and language a focus of intense study. When you write, you don’t want anything to obstruct your message. Bad writing, more than anything else, will prevent your readers from learning what you intend to communicate. This post presents a few of the principles and guidelines that I use when writing for professional developers. Answer the Three Important Questions What are you going to say? What is your message? What are the key Read More... Posted Wednesday, October 22, 2008 11:24 AM from Eric White's Blog | (Comments Off) Filed under: Writing

• Trouble with dreaded "An attempt has been made to Attach or Add an entity that is not new..."

  Hi. I have a datacontext that contains two tables, Books & Authors (1 to many ***'n Auth -> Books). I noticed that when I load an author (serialized on an asp.net app) to update the authors' bio (context.Authors.Attach(author, true)), I get the " 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 seen two workarounds for this. 1) Detach child objects (in this case, detach Books from an author when Read More... Posted Wednesday, October 22, 2008 2:50 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Nested sub-query LINQ to SQL

  Hi. How do I do a nested sub query that is 3 levels deep... I have CountryPackages where one country can have multiple Packages in it and one package can have multiple Images linked to it. So all I want is the LINQ to show me a random Package(Name, ID) in this Country with one random Image(imagePath) from that Package. Thank you Sarel Ps. I know how to get a random image from a package, I have a a SQL function called GetNewID() and I use let in the orderby and I limit the rows to 1 with FirstOrDefault Read More... Posted Wednesday, October 22, 2008 12:16 AM from MSDN Forums: LINQ Project General | (Comments Off)

• Search table column for values

  Hi All How would I do this in linq WHERE [dbo] . [albums] . [albumName] Like '%' + @albumName + '%' Thanks Read More... Posted Tuesday, October 21, 2008 9:43 PM from MSDN Forums: LINQ Project General | (Comments Off)

• using Contains with System.Linq.Dynamic

  Hi... im really not comfortable with dynamic sql and linq. I used the system.linq.dynamic framework and worked it out pretty well until needed to use the like % operator (or contain if you like). public IEnumerable getBasicGuestListFiltered(ReplikaAnsat replikaAnsatWhoAmI, int acceslevel, Boolean alle, Boolean mine, Boolean tilMig, DateTime? fraDato, DateTime? tilDato, String gæstNavn) { GæstelistenDataContext db = new GæstelistenDataContext(); IQueryable query ; query = from gl in db.Gæstelistes Read More... Posted Tuesday, October 21, 2008 6:00 PM from MSDN Forums: LINQ Project General | (Comments Off)

• Are there any site like this in spanish?