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  • Using Linq on a Dataset

    - by JasonMHirst
    Can someone enlighthen me with regards to Linq please? I have a dataset that is populated via a SQL Stored Procedure, the format of which is below: Country | Brand | Variant | 2004 | 2005 | 2006 | 2007 | 2008 The number of rows varies between 50 and several thousand. What I'm trying to do is use Linq to interrogate the dataset (there will be several Linq queries based on user options), but a simple example would be to SUM the year columns based on Brand. I have the following that I believe creates a template for me to work with: But from here on I'm absolutely stuck! sqlDA.Fill(ds, "Profiler") Dim brandsQuery = From cust In ds.Tables(0).AsEnumerable() Select _BrandName = cust.Item("BrandName"), _y0 = cust.Item("1999"), _y1 = cust.Item("2004"), _y2 = cust.Item("2005"), _y3 = cust.Item("2006"), _y4 = cust.Item("2007"), _y5 = cust.Item("2008") I'm tried to look at examples, but can't see any that are VB.Net based and/or show me how to Sum/Group. Can someone please provide an example so I can perhaps learn from it. Thanks.

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  • 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.

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  • 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

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  • 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>

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  • Mysterious constraints problem with SQL Server 2000

    - by Ramon
    Hi all I'm getting the following error from a VB NET web application written in VS 2003, on framework 1.1. The web app is running on Windows Server 2000, IIS 5, and is reading from a SQL server 2000 database running on the same machine. System.Data.ConstraintException: Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints. at System.Data.DataSet.FailedEnableConstraints() at System.Data.DataSet.EnableConstraints() at System.Data.DataSet.set_EnforceConstraints(Boolean value) at System.Data.DataTable.EndLoadData() at System.Data.Common.DbDataAdapter.FillFromReader(Object data, String srcTable, IDataReader dataReader, Int32 startRecord, Int32 maxRecords, DataColumn parentChapterColumn, Object parentChapterValue) at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, String srcTable, IDataReader dataReader, Int32 startRecord, Int32 maxRecords) at System.Data.Common.DbDataAdapter.FillFromCommand(Object data, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) at System.Data.Common.DbDataAdapter.Fill(DataSet dataSet) The problem appears when the web app is under a high load. The system runs fine when volume is low, but when the number of requests becomes high, the system starts rejecting incoming requests with the above exception message. Once the problem appears, very few requests actually make it through and get processed normally, about 2 in every 30. The vast majority of requests fail, until a SQL Server restart or IIS reset is performed. The system then start processing requests normally, and after some time it starts throwing the same error. The error occurs when a data adapter runs the Fill() method against a SELECT statement, to populate a strongly-typed dataset. It appears that the dataset does not like the data it is given and throws this exception. This error occurs on various SELECT statements, acting on different tables. I have regenerated the dataset and checked the relevant constraints, as well as the table from which the data is read. Both the dataset definition and the data in the table are fine. Admittedly, the hardware running both the web app and SQL Server 2000 is seriously outdated, considering the numbers of incoming requests it currently receives. The amount of RAM consumed by SQL Server is dynamically allocated, and at peak times SQL Server can consume up to 2.8 GB out of a total of 3.5 GB on the server. At first I suspected some sort of index or database corruption, but after running DBCC CHECKDB, no errors were found in the database. So now I'm wondering whether this error is a result of the hardware limitations of the system. Is it possible for SQL Server to somehow mess up the data it's supposed to pass to the dataset, resulting in constraint violation due to, say, data type/length mismatch? I tried accessing the RowError messages of the data rows in the retrieved dataset tables but I kept getting empty strings. I know that HasErrors = true for the datatables in question. I have not set the EnableConstraints = false, and I don't want to do that. Thanks in advance. Ray

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  • 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)

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  • 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.

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  • 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.

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  • 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?

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  • 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

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  • How can I use linq to build an object from 1 row of data?

    - by Hcabnettek
    Hi All, I have a quick linq question. I have a stored proc that should return one row of data. I would like to use a lambda to build an object. Here's what I'm currently doing which works, but I know I should be able to use First instead of Select except I can't seem to get the syntax correct. Can anyone straighten me out here? Thanks for any help. var location = new GeoLocationDC(); DataSet ds = db.ExecuteDataSet(dbCommand); if(ds.Tables[0].Rows.Count == 1) { var rows = ds.Tables[0].AsEnumerable(); var x = rows.Select( c => new GeoLocationDC { Latitude = Convert.ToInt32(c.Field<string>("LATITUDE")), Longitude = Convert.ToInt32(c.Field<string>("LONGITUDE")) }).ToList(); if(x.Count > 0 ) { location = x[0]; } Cheers, ~ck }

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  • VB 2008 or VB 2010 Dataset help

    - by Diabolo
    I have three forms similar to the one in the link. I want add a Total textbox to every form. The total will add the values that will be entered in the montant textbox. So the total will take the specific value of that texbox for all the entries that the user will have and add them. How I can do so???? Thanks http://i1006.photobucket.com/albums/af189/diaboloent/OneForm.jpg

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  • 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!

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  • Huge dataset point in polygon in .net (collision detection)

    - by Rickard Liljeberg
    I have a pretty big mesh with polygons, usually triangles but sometimes rectangles. Each point in my mesh has a value (value has nothing to do with coordinates). Now I am creating a second mesh in the same coordinate-space as the old mesh. I now want to interpolate out values for all points (vertices) in the new mesh using the values from the old mesh. Now I could loop each polygon in the new mesh and detect which old vertices are in each polygon by making 2d collision detection (altho even this I don't get to function properly so if anyone has simple and fast code for 2d collision detection (triangle is enough) I would gladly see it). However to my main point again. looping each old vertice for each new polygon seems less than efficient. is there a better way?

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  • strongly typed dataset Insert record with C# problem

    - by Eyla
    Greetings, I'm using strongly typed data-set in windows application and I'm creating table adapter object to call insert function. The problem that there is nothing inserted to the table after calling the function and no error produced. here is my code: public PacketsDBDataSet1TableAdapters.packetsTableAdapter ds = new PacketsDBDataSet1TableAdapters.packetsTableAdapter(); private void btnSavePacketsInFile_Click(object sender, EventArgs e) { byte[] w = null; ds.InsertPackets("s", "s", "s", "s", "s", w); } I'm using same same code with ASP.Net but it is working OK. any advice??

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  • 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

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  • DataSet with many OR clauses

    - by Silvan
    Hello :) I've got a little problem with a query which I create in the Visual Studio Designer. I need a query with a lot of 'OR'-clauses for the same column. I found the operator 'IN', but I don't know how to use that in the Visual Studio Designer: Example IN: SELECT EmployeeID, FirstName, LastName, HireDate, City FROM Employees WHERE City IN ('Seattle', 'Tacoma', 'Redmond') I tried to do it in this way: SELECT [MachineryId], [ConstructionSiteId], [DateTime], [Latitude], [Longitude], [HoursCounter] FROM [PositionData] WHERE [MachineryID] IN @MachineryIDs But this doesn't work. Is there another way to handle a lot of OR clauses? Thank you very much for your help.

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  • removing null valued columns from dataset in asp .net

    - by N.Sai Harish
    I have a table which stores data with null valued columns for some entries .I want to retrieve only Not null data to the detail view. I tried the following foreach(string strTableField in (objDataSet.Tables[0].Columns[i])) { if(objDataSet.Tables[0].Columns[i].Equals(null)) { objDataSet.Tables[0].Columns.Remove(strTableField); objDataSet.Tables[0].AcceptChanges(); } i++; } but it is giving error .. Pls help me reg this ...

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  • 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?

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  • Dataset Binding stored procedures update/insert/delete

    - by Jin
    Hi all, I am currently having a problem since the DB has been changed. I am using Datasets for a c# application, and there is a user management system. For the security issues, our current DB design is like user log into app. DB returns a session ID On use of any other stored procedures, a session ID must be specified. BUT, the DB didn't request session ID before. since I am using the datasets, I used update/insert/delete stored procedures with "TableAdaptor Configuration Wizard". Bind Commands to Existing Stored Procedures (choose stored procedures to call and specify any reuiqred parameters) Now, it seems like I have to specify session ID for Insert/Update/Delete stored procedures. How do I specify session ID parameter here? It seems like I have to pick one return parameter variable from a select statement. Thanks,

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