Search Results

Search found 19165 results on 767 pages for 'custom linq providers'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 17/767 | < Previous Page | 13 14 15 16 17 18 19 20 21 22 23 24  | Next Page >

  • What is the differnce between "LINQ to Entities", "LINQ to SQL" and "LINQ to Dataset".

    - by Marcel
    Hi all, I'm working for quite a while now with LINQ. However, it remained still a bit of a mystery what are the real differences between the mentioned flavours of LINQ. The successful answer will contain a short differentiation between them. What is the main goal if it, what is the benefit, and is there a performance impact... P.S. I know that there are a lot of information sources out there, but I look for a kind of a "cheat sheet" which instructs a newbie where to head to for a specific goal.

    Read the article

  • How can I stop an auto-generated Linq to SQL class from loading ALL data?

    - by Gary McGill
    I have an ASP.NET MVC project, much like the NerdDinner tutorial example. (I'm using MVC 2, but followed the NerdDinner tutorial in order to create it). As per the instructions in part 3 of the tutorial, I've created a Linq-to-SQL model of my database by creating a "Linq to SQL Classes" (.dbml) surface, and dropping my database tables onto it. The designer has automatically added relationships between the generated classes based on my database tables. Let's say that my classes are as per the NerdDinner example, so I have Dinner and RSVP tables, where each Dinner record is associated with many RSVP records - hence in the generated classes, the Dinner object has a RSVPs property which is a list of RSVP objects. My problem is this: it appears (and I'd be gladly proved wrong on this) that as soon as I access a Dinner object, it's loading all of the corresponding RSVP objects, even if I don't use the RSVPs member. First question: is this really the default behavior for the generated classes? In my particular situation, the object graph contains many more tables (which have an order of magnitude more records), and so this is disastrous behaviour - I'd be loading tons of data when all I want to do is show the details of a single parent record. Second question: are there any properties exposed through the designer UI that would let me modify this behavior? (I can't find any). Third question: I've seen a description of how to control the loading of related records in a DataContext by using a DataShape object associated with the DataContext. Is that what I'm meant to do, and if so are there any tutorials like the NerdDinner one that would show not only how to do it, but also suggest a 'pattern' for normal use?

    Read the article

  • How can I remove an "ALMOST" Duplicate using LINQ? ( OR SQL? )

    - by Atomiton
    This should be and easy one for the LINQ gurus out there. I'm doing a complex Query using UNIONS and CONTAINSTABLE in my database to return ranked results to my application. I'm getting duplicates in my returned data. This is expected. I'm using CONTAINSTABLE and CONTAINS to get all the results I need. CONTAINSTABLE is ranked by SQL and CONTAINS (which is run only on the Keywords field ) is hard-code-ranked by me. ( Sorry if that doesn't make sense ) Anyway, because the tuples aren't identical ( their rank is different ) a duplicate is returned. I figure the best way to deal with this is use LINQ. I know I'll be using the Distinct() extension method, but do I have to implement the IEqualityComparer interface? I'm a little fuzzy on how to do this. For argument's sake, say my resultset is structured like this class: class Content { ContentID int //KEY Rank int Description String } If I have a List<Content> how would I write the Distinct() method to exclude Rank? Ideally I'd like to keep the Content's highest Rank. SO, if one Content's RAnk is 112 and the other is 76. I'd like to keep the 112 rank. Hopefully I've given enough information.

    Read the article

  • What is the return type for a anonymous linq query select? What is the best way to send this data ba

    - by punkouter
    This is a basic question. I have the basic SL4/RIA project set up and I want to create a new method in the domain service and return some data from it. I am unsure the proper easiest way to do this.. Should I wrap it up in a ToList()? I am unclear how to handle this anonymous type that was create.. what is the easiest way to return this data? public IQueryable<ApplicationLog> GetApplicationLogsGrouped() { var x = from c in ObjectContext.ApplicationLogs let dt = c.LogDate group c by new { y = dt.Value.Year, m = dt.Value.Month, d = dt.Value.Day } into mygroup select new { aaa = mygroup.Key, ProductCount = mygroup.Count() }; return x; // return this.ObjectContext.ApplicationLogs.Where(r => r.ApplicationID < 50); } Cannot implicitly convert type 'System.Linq.IQueryable<AnonymousType#1>' to 'System.Linq.IQueryable<CapRep4.Web.ApplicationLog>'. An explicit conversion exists (are you missing a cast?) 58 20 CapRep4.Web

    Read the article

  • LINQ to SQL - Why can't you use a WHERE after an ORDER BY?

    - by MCS
    The following code: // select all orders var orders = from o in FoodOrders where o.STATUS = 1 order by o.ORDER_DATE descending select o; // if customer id is specified, only select orders from specific customer if (customerID!=null) { orders = orders.Where(o => customerID.Equals(o.CUSTOMER_ID)); } gives me the following error: Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Linq.IOrderedQueryable'. An explicit conversion exists (are you missing a cast?) I fixed the error by doing the sorting at the end: // select all orders var orders = from o in FoodOrders where o.STATUS = 1 select o; // if customer id is specified, only select orders from specific customer if (customerID!=null) { orders = orders.Where(o => customerID.Equals(o.CUSTOMER_ID)); } // I'm forced to do the ordering here orders = orders.OrderBy(o => o.ORDER_DATE).Reverse(); But I'm wondering why is this limitation in place? What's the reason the API was designed in such a way that you can't add a where constraint after using an order by operator?

    Read the article

  • LINQ to Entities question about orderby and null collections.

    - by Chevex
    I am currently developing a forum. I am new to LINQ and EF. In my forum I have a display that shows a list of topics with the most recent topics first. The problem is that "most recent" is relative to the topic's replies. So I don't want to order the list by the topic's posted date, rather I want to order the list by the topic's last reply's posted date. So that topics with newer replies pop back to the top of the list. This is rather simple if I knew that every topic had at least one reply; I would just do this: var topicsQuery = from x in board.Topics orderby x.Replies.Last().PostedDate descending select x; However, in many cases the topic has no replies. In which case I would like to use the topic's posted date instead. Is there a way within my linq query to order by x.PostedDate in the event that the topic has no replies? I'm getting confused by this and any help would be appreciated. With the above query, it breaks on topics with no replies because of the x.Replies.Last() which assumes there are replies. LastOrDefault() doesn't work because I need to access the PostedDate property which also assumes a reply exists. Thanks in advance for any insight.

    Read the article

  • How to add second JOIN clause in Linq To Sql?

    - by Refracted Paladin
    I am having a lot of trouble coming up with the Linq equivalent of this legacy stored procedure. The biggest hurdle is it doesn't seem to want to let me add a second 'clause' on the join with tblAddress. I am getting a Cannot resolve method... error. Can anyone point out what I am doing wrong? Below is, first, the SPROC I need to convert and, second, my LINQ attempt so far; which is FULL OF FAIL! Thanks SELECT dbo.tblPersonInsuranceCoverage.PersonInsuranceCoverageID, dbo.tblPersonInsuranceCoverage.EffectiveDate, dbo.tblPersonInsuranceCoverage.ExpirationDate, dbo.tblPersonInsuranceCoverage.Priority, dbo.tblAdminInsuranceCompanyType.TypeName AS CoverageCategory, dbo.tblBusiness.BusinessName, dbo.tblAdminInsuranceType.TypeName AS TypeName, CASE WHEN dbo.tblAddress.AddressLine1 IS NULL THEN '' ELSE dbo.tblAddress.AddressLine1 END + ' ' + CASE WHEN dbo.tblAddress.CityName IS NULL THEN '' ELSE '<BR>' + dbo.tblAddress.CityName END + ' ' + CASE WHEN dbo.tblAddress.StateID IS NULL THEN '' WHEN dbo.tblAddress.StateID = 'ns' THEN '' ELSE dbo.tblAddress.StateID END AS Address FROM dbo.tblPersonInsuranceCoverage LEFT OUTER JOIN dbo.tblInsuranceCompany ON dbo.tblPersonInsuranceCoverage.InsuranceCompanyID = dbo.tblInsuranceCompany.InsuranceCompanyID LEFT OUTER JOIN dbo.tblBusiness ON dbo.tblBusiness.BusinessID = dbo.tblInsuranceCompany.BusinessID LEFT OUTER JOIN dbo.tblAddress ON dbo.tblAddress.BusinessID = dbo.tblBusiness.BusinessID and tblAddress.AddressTypeID = 'b' LEFT OUTER JOIN dbo.tblAdminInsuranceCompanyType ON dbo.tblPersonInsuranceCoverage.InsuranceCompanyTypeID = dbo.tblAdminInsuranceCompanyType.InsuranceCompanyTypeID LEFT OUTER JOIN dbo.tblAdminInsuranceType ON dbo.tblPersonInsuranceCoverage.InsuranceTypeID = dbo.tblAdminInsuranceType.InsuranceTypeID WHERE tblPersonInsuranceCoverage.PersonID = @PersonID var coverage = from insuranceCoverage in context.tblPersonInsuranceCoverages where insuranceCoverage.PersonID == personID join insuranceCompany in context.tblInsuranceCompanies on insuranceCoverage.InsuranceCompanyID equals insuranceCompany.InsuranceCompanyID join address in context.tblAddresses on insuranceCompany.tblBusiness.BusinessID equals address.BusinessID where address.AddressTypeID = 'b' select new { insuranceCoverage.PersonInsuranceCoverageID, insuranceCoverage.EffectiveDate, insuranceCoverage.ExpirationDate, insuranceCoverage.Priority, CoverageCategory = insuranceCompany.tblAdminInsuranceCompanyType.TypeName, insuranceCompany.tblBusiness.BusinessName, TypeName = insuranceCoverage.InsuranceTypeID, Address = };

    Read the article

  • How can I use a compound condition in a join in Linq?

    - by Gary McGill
    Let's say I have a Customer table which has a PrimaryContactId field and a SecondaryContactId field. Both of these are foreign keys that reference the Contact table. For any given customer, either one or two contacts may be stored. In other words, PrimaryContactId can never be NULL, but SecondaryContactId can be NULL. If I drop my Customer and Contact tables onto the "Linq to SQL Classes" design surface, the class builder will spot the two FK relationships from the Customer table to the Contact table, and so the generated Customer class will have a Contact field and a Contact1 field (which I can rename to PrimaryContact and SecondaryContact to avoid confusion). Now suppose that I want to get details of all the contacts for a given set of customers. If there was always exactly one contact then I could write something like: from customer in customers join contact in contacts on customer.PrimaryContactId equals contact.id select ... ...which would be translated into something like: SELECT ... FROM Customer INNER JOIN Contact ON Customer.FirstSalesPersonId = Contact.id But, because I want to join on both the contact fields, I want the SQL to look something like: SELECT ... FROM Customer INNER JOIN Contact ON Customer.FirstSalesPersonId = Contact.id OR Customer.SecondSalesPersonId = Contact.id How can I write a Linq expression to do that?

    Read the article

  • How do I add a where filter using the original Linq-to-SQL object in the following scenario

    - by GenericTypeTea
    I am performing a select query using the following Linq expression: Table<Tbl_Movement> movements = context.Tbl_Movement; var query = from m in movements select new MovementSummary { Id = m.DocketId, Created = m.DateTimeStamp, CreatedBy = m.Tbl_User.FullName, DocketNumber = m.DocketNumber, DocketTypeDescription = m.Ref_DocketType.DocketType, DocketTypeId = m.DocketTypeId, Site = new Site() { Id = m.Tbl_Site.SiteId, FirstLine = m.Tbl_Site.FirstLine, Postcode = m.Tbl_Site.Postcode, SiteName = m.Tbl_Site.SiteName, TownCity = m.Tbl_Site.TownCity, Brewery = new Brewery() { Id = m.Tbl_Site.Ref_Brewery.BreweryId, BreweryName = m.Tbl_Site.Ref_Brewery.BreweryName }, Region = new Region() { Description = m.Tbl_Site.Ref_Region.Description, Id = m.Tbl_Site.Ref_Region.RegionId } } }; I am also passing in an IFilter class into the method where this select is performed. public interface IJobFilter { int? PersonId { get; set; } int? RegionId { get; set; } int? SiteId { get; set; } int? AssetId { get; set; } } How do I add these where parameters into my SQL expression? Preferably I'd like this done in another method as the filtering will be re-used across multiple repositories. Unfortunately when I do query.Where it has become an IQueryable<MovementSummary>. I'm assuming it has become this as I'm returning an IEnumerable<MovementSummary>. I've only just started learning LINQ, so be gentle.

    Read the article

  • Why are my bound parameters all identical (using Linq)?

    - by Scott Stafford
    When I run this snippet of code: string[] words = new string[] { "foo", "bar" }; var results = from row in Assets select row; foreach (string word in words) { results = results.Where(row => row.Name.Contains(word)); } I get this SQL: -- Region Parameters DECLARE @p0 VarChar(5) = '%bar%' DECLARE @p1 VarChar(5) = '%bar%' -- EndRegion SELECT ... FROM [Assets] AS [t0] WHERE ([t0].[Name] LIKE @p0) AND ([t0].[Name] LIKE @p1) Note that @p0 and @p1 are both bar, when I wanted them to be foo and bar. I guess Linq is somehow binding a reference to the variable word rather than a reference to the string currently referenced by word? What is the best way to avoid this problem? (Also, if you have any suggestions for a better title for this question, please put it in the comments.) Note that I tried this with regular Linq also, with the same results (you can paste this right into Linqpad): string[] words = new string[] { "f", "a" }; string[] dictionary = new string[] { "foo", "bar", "jack", "splat" }; var results = from row in dictionary select row; foreach (string word in words) { results = results.Where(row => row.Contains(word)); } results.Dump(); Dumps: bar jack splat

    Read the article

  • How to Create Custom Personalized Maps in Google Maps [Video]

    - by Asian Angel
    Though the custom maps feature has been out for a bit, you may have forgotten about it or it may all be new for you. Either way this wonderful video shows you how to create your own custom maps and enjoy an awesome feature of this popular Google service. ‘My Maps’ is mentioned in the video above, but is now referred to as ‘My Places’ in Google Maps (as seen below). There is also a nice interactive tutorial available. How to Use an Xbox 360 Controller On Your Windows PC Download the Official How-To Geek Trivia App for Windows 8 How to Banish Duplicate Photos with VisiPic

    Read the article

  • Reading XML element & child nodes using LINQ in Vb.net- help me in where condition :(

    - by New Linq Baby
    Hi, I am new in LINQ world. I need an urgent help in reading the xml elements using LINQ with specific where condition. I need to find the max air_temp for a county i.e where county name = "Boone" and hour id = "06/03/2009 09:00CDT" i tried something like below, but no luck : Dim custs As IEnumerable = From c In Element.Load("C:\meridian.xml").Elements("county") _ Select c.Elements("hour").Elements("air_temp").Max() For Each x In custs Response.Write(custs(0).ToString()) Next ------------------- here is the xml file : <forecasts> <issued>06/02/2009 12:00CDT</issued> - <county name="Adair"> - <hour id="06/02/2009 12:00CDT"> <air_temp>61</air_temp> <cloud_cover>overcast</cloud_cover> <dew_point>59</dew_point> <precip_prob>90</precip_prob> <precip_rate>0.12</precip_rate> <precip_type>rain</precip_type> <snow_rate>0.0</snow_rate> <wind_direction>NE</wind_direction> <wind_speed>12</wind_speed> <dew_point_confidence>-3/+3</dew_point_confidence> <road_temp>64</road_temp> <road_frost_prob>0</road_frost_prob> <road_potential_evap_rate>429</road_potential_evap_rate> <road_temp_confidence>-3/+2</road_temp_confidence> <dew_point_confidence>-3/+3</dew_point_confidence> <bridge_temp>63</bridge_temp> <bridge_temp_confidence>-4/+2</bridge_temp_confidence> <bridge_frost>NO</bridge_frost> </hour> - <hour id="06/02/2009 13:00CDT"> <air_temp>61</air_temp> <cloud_cover>overcast</cloud_cover> <dew_point>60</dew_point> <precip_prob>70</precip_prob> <precip_rate>0.01</precip_rate> <precip_type>rain</precip_type> <snow_rate>0.0</snow_rate> <wind_direction>ENE</wind_direction> <wind_speed>10</wind_speed> <dew_point_confidence>-3/+3</dew_point_confidence> <road_temp>65</road_temp> <road_frost_prob>0</road_frost_prob> <road_potential_evap_rate>411</road_potential_evap_rate> <road_temp_confidence>-3/+2</road_temp_confidence> <dew_point_confidence>-3/+3</dew_point_confidence> <bridge_temp>64</bridge_temp> <bridge_temp_confidence>-4/+1</bridge_temp_confidence> <bridge_frost>NO</bridge_frost> </hour>

    Read the article

  • LINQ to SQL - Save an entity without creating a new DataContext?

    - by aximili
    I get this error Cannot add an entity with a key that is already in use when I try to save an Item [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(Item item) { Global.DataContext.Items.Attach(item); Global.DataContext.SubmitChanges(); return View(item); } That's because I cannot attach the item to the static global DataContext. Is it possible to save an item without creating a new DataContext? (I am very new to LINQ)

    Read the article

  • How to detect if a LINQ enumeration is materialized?

    - by Peter Lillevold
    Is there some way of detecting whether an enumerable built using LINQ (to Objects in this case) have been materialized or not? Other than trying to inspect the type of the underlying collection? Specifically, since enumerable.ToArray() will build a new array even if the underlying collection already is an array I'm looking for a way of avoiding ToArray() being called twice on the same collection.

    Read the article

  • How to use Linq to select and group complex child object from a parents list.

    - by Daoming Yang
    How to use Linq to select and group complex child object from a parents list. I have an OrderList each of order object has a OrderProductVariantList(OrderLineList), and each of OrderProductVariant object has ProductVariant, and then the ProductVariant object will have a Product object which contains product information. My goal is to select and group the most popular products from the order list. Can anyone help me with this? Many thanks.

    Read the article

  • How to map LINQ EntitySet to List property in property setter?

    - by jlp
    In my model I have these entities: public interface IOrder { string Name {get;set;} List<IProduct> OrderedProducts {get;set;} } public interface IProduct {} In partial class generated by linq-to-sql I map these properties on my entity properties: public partial class Order : IOrder { List<IProduct> OrderedProducts { get { return this.L2SQLProducts.Cast<IProduct>.ToList(); } set { this.L2SQLProducts = ??? } } } How should setter look like?

    Read the article

  • How can I do a multi level parent-child sort using Linq?

    - by Tenacious T
    How can I do a multi-level parent-child sort using Linq if I have a table structure like the one below: [Table: Sections] Id Seq Name ParentSectionId 1 1 TOP NULL 2 1 AAAA 1 3 2 SSSS 1 4 3 DDDD 1 5 1 SectionA1 2 6 2 SectionA2 2 7 1 SectionS1 3 8 3 ASummary 2 Expected sort result: TOP AAAA SectionA1 SectionA2 ASummary SSSS SectionS1 DDDD

    Read the article

  • nhibernate activerecord linq Contains problem

    - by Robert Ivanc
    Hi, I am having problems with the following query in Castle ActiveRecord 2.12: var q = from o in SodisceFMClientVAR.Queryable where taxnos2.Contains(o.TaxFileNo) select o; taxNos2 is an array of strings. When run I get an exception: + InnerException {"Index was out of range. Must be non-negative and less than the size of the collection.\r\nParameter name: index"} System.Exception {System.ArgumentOutOfRangeException} StackTrace " at Castle.ActiveRecord.ActiveRecordBase.ExecuteQuery(IActiveRecordQuery query)\r\n at Castle.ActiveRecord.Linq.LinqResultWrapper`1.Populate()\r\n at Castle.ActiveRecord.Linq.LinqResultWrapper`1.GetEnumerator()\r\n at NHibernate.Linq.Query`1.GetEnumerator()\r\n at System.Linq.Buffer`1..ctor(IEnumerable`1 source)\r\n at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)\r\n at prosoft.skb.insolventnostDataAccess.InsolventnostDataAccAR.GetOurUsersListLS(ICollection`1 taxNos) in C:\\svn\\skb\\insolventnostWithAR\\prosoft.skb.insolventnostDataAccess\\InsolventnostDataAR.cs:line 214\r\n at prosoft.skb.insolventnostDataFromWS.InsolventnostFromWS.filterByOurUsers(IEnumerable`1 odprtiPostopki) in C:\\svn\\skb\\insolventnostWithAR\\prosoft.skb.insolventnostDataFromWS\\InsolventnostFromWS.cs:line 237\r\n at prosoft.skb.insolventnostDataFromWS.InsolventnostFromWS.SyncData() in C:\\svn\\skb\\insolventnostWithAR\\prosoft.skb.insolventnostDataFromWS\\InsolventnostFromWS.cs:line 53" string Does Contains even work in linq for nhibernate? I couldn't find anything via google... Is there a workaround? Thanks!

    Read the article

  • Converting F# Quotations into LINQ Expressions

    - by forki23
    Hi, I can convert a quotation of type Expr<'a -> 'b> to a Linq expression via the following snippet: /// Converts a F# Expression to a LINQ Lambda let toLambda (exp:Expr) = let linq = exp.ToLinqExpression() :?> MethodCallExpression linq.Arguments.[0] :?> LambdaExpression /// Converts a Lambda quotation into a Linq Lamba Expression with 1 parameter let ToLinq (exp : Expr<'a -> 'b>) = let lambda = toLambda exp Expression.Lambda<Func<'a, 'b>>(lambda.Body, lambda.Parameters) Now I want to convert a quotation of type Expr<'a * 'b -> 'c> or maybe even Expr<'a -> 'b -> 'c> to a Linq Lambda Expression of type Expression<Func<'a,'b'c>>. How can I do this? Regards, forki

    Read the article

  • Developing a custom-validation in asp.net for specific control and criteria

    - by Gaurav
    Hello There is another relevant question asked Validation Check in asp.net In the same scenario we need a custom validator control which will alert user for any wrong entry. This will work like this : Developer will pass the control-name, input-value and format-required For instance like for textbox it can be: txtName,txtName.Text, allow-alphabets-only The accordingly format if the user input is invalid he/she will be got prompt. Please suggest the right way to do the smae. Thanks in advance.

    Read the article

  • LINQ Queries And Context

    - by Soo
    Hello SO, I have a slight issue with some code I'm writing if(parameter == 1) { var linq = from a in db.table select a; } else { var linq = from a in db.table where a.id = 1 select a; } foreach(var b in linq) { ... } So basically what's going on is that the variable "linq" is different depending on the value of "parameter". When I try to loop through "linq" with my foreach loop, I get an error about how linq doesn't exist in the current context. What is the best way to work around this type of issue?

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 13 14 15 16 17 18 19 20 21 22 23 24  | Next Page >