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  • I can't understand GroupJoin where i will need it in database relationships.

    - by Freshblood
    Hello Everybody I am thinking 5-6 hours to understand something about GroupJoin. I am talking about query with linq for Database tables.I understand what Join and GroupJoin does but I really couldn't understand where i will need it.I feel that Join does all what i will need but if there is something which Join can't without GroupJoin so i feel that situation is meaningless or useless. For example: Persons table in relation with Phones and Phones table hold foreign keys of Persons and one person can have one more phone number.If we want to brings all persons who has phone numbers and who hasn't too so we will need GroupJOin but what for we will need this query ? Can u give me good reason , example or explenation for using GroupJoin ?

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  • seperated mysql statement query in php

    - by stone
    So, I can run the following statements from within mysql itself successfully. SET @fname = 'point1'; SELECT * FROM country WHERE name=@fname;` But when I try to pass the query through php like this and run it, I get an error on the second line $query = "SET @fname = 'point1';"; $query .= "SELECT * FROM country WHERE name=@fname;";

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  • Help with SQL query

    - by user154301
    Hello, I have list of DateTime values, and for each value I need to fetch something from the database. I would like to do this with one query. I know it's possible to pass a table (list) to the stored procedure, but Im not sure how to write the query itself. Let's say I have the following table: CREATE TABLE Shows( ShowId [int] NOT NULL, StartTime DateTime NOT NULL, EndTime DateTime NOT NULL ) and an array of dates DECLARE @myDateArray MyCustomDateArrayType Now, if I were fetching a single item, I would write a query like this: SELECT * FROM Shows WHERE StartTime > @ArrayItem and @ArrayItem < EndTime where @ArrayItem is an item from @myDateArray . But how do I formulate the query that would fetch the information for all array items? Thanks!

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  • SQL SERVER – CXPACKET – Parallelism – Usual Solution – Wait Type – Day 6 of 28

    - by pinaldave
    CXPACKET has to be most popular one of all wait stats. I have commonly seen this wait stat as one of the top 5 wait stats in most of the systems with more than one CPU. Books On-Line: Occurs when trying to synchronize the query processor exchange iterator. You may consider lowering the degree of parallelism if contention on this wait type becomes a problem. CXPACKET Explanation: When a parallel operation is created for SQL Query, there are multiple threads for a single query. Each query deals with a different set of the data (or rows). Due to some reasons, one or more of the threads lag behind, creating the CXPACKET Wait Stat. There is an organizer/coordinator thread (thread 0), which takes waits for all the threads to complete and gathers result together to present on the client’s side. The organizer thread has to wait for the all the threads to finish before it can move ahead. The Wait by this organizer thread for slow threads to complete is called CXPACKET wait. Note that not all the CXPACKET wait types are bad. You might experience a case when it totally makes sense. There might also be cases when this is unavoidable. If you remove this particular wait type for any query, then that query may run slower because the parallel operations are disabled for the query. Reducing CXPACKET wait: We cannot discuss about reducing the CXPACKET wait without talking about the server workload type. OLTP: On Pure OLTP system, where the transactions are smaller and queries are not long but very quick usually, set the “Maximum Degree of Parallelism” to 1 (one). This way it makes sure that the query never goes for parallelism and does not incur more engine overhead. EXEC sys.sp_configure N'cost threshold for parallelism', N'1' GO RECONFIGURE WITH OVERRIDE GO Data-warehousing / Reporting server: As queries will be running for long time, it is advised to set the “Maximum Degree of Parallelism” to 0 (zero). This way most of the queries will utilize the parallel processor, and long running queries get a boost in their performance due to multiple processors. EXEC sys.sp_configure N'cost threshold for parallelism', N'0' GO RECONFIGURE WITH OVERRIDE GO Mixed System (OLTP & OLAP): Here is the challenge. The right balance has to be found. I have taken a very simple approach. I set the “Maximum Degree of Parallelism” to 2, which means the query still uses parallelism but only on 2 CPUs. However, I keep the “Cost Threshold for Parallelism” very high. This way, not all the queries will qualify for parallelism but only the query with higher cost will go for parallelism. I have found this to work best for a system that has OLTP queries and also where the reporting server is set up. Here, I am setting ‘Cost Threshold for Parallelism’ to 25 values (which is just for illustration); you can choose any value, and you can find it out by experimenting with the system only. In the following script, I am setting the ‘Max Degree of Parallelism’ to 2, which indicates that the query that will have a higher cost (here, more than 25) will qualify for parallel query to run on 2 CPUs. This implies that regardless of the number of CPUs, the query will select any two CPUs to execute itself. EXEC sys.sp_configure N'cost threshold for parallelism', N'25' GO EXEC sys.sp_configure N'max degree of parallelism', N'2' GO RECONFIGURE WITH OVERRIDE GO Read all the post in the Wait Types and Queue series. Additionally a must read comment of Jonathan Kehayias. Note: The information presented here is from my experience and I no way claim it to be accurate. I suggest you all to read the online book for further clarification. All the discussion of Wait Stats over here is generic and it varies from system to system. It is recommended that you test this on the development server before implementing on the production server. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: DMV, Pinal Dave, PostADay, SQL, SQL Authority, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • How to Loop through LINQ results (VB.NET)

    - by rockinthesixstring
    I've got some code to try and loop through LINQ results, but it doesn't seem to be working. HERE'S THE CODE Public Sub ProcessRequest(ByVal context As System.Web.HttpContext) Implements System.Web.IHttpHandler.ProcessRequest ' the page contenttype is plain text' HttpContext.Current.Response.ContentType = "text/plain" ' store the querystring as a variable' Dim qs As Nullable(Of Integer) = Integer.TryParse(HttpContext.Current.Request.QueryString("ID"), Nothing) ' use the RegionsDataContext' Using RegionDC As New DAL.RegionsDataContext 'create a (q)uery variable' Dim q As Object ' if the querystring PID is not blank' ' then we want to return results based on the PID' If Not qs Is Nothing Then ' that fit within the Parent ID' q = (From r In RegionDC.bt_Regions _ Where r.PID = qs _ Select r.Region).ToArray ' now we loop through the array' ' and write out the ressults' For Each item As DAL.bt_Region In q HttpContext.Current.Response.Write(item.Region & vbCrLf) Next End If End Using End Sub HERE'S THE ERROR Public member 'Region' on type 'String' not found. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.MissingMemberException: Public member 'Region' on type 'String' not found. Source Error: Line 33: ' and write out the ressults Line 34: For Each item In q Line 35: HttpContext.Current.Response.Write(item.Region & vbCrLf) Line 36: Next Line 37: Source File: E:\Projects\businesstrader\App_Code\Handlers\RegionsAutoComplete.vb Line: 35 Stack Trace: [MissingMemberException: Public member 'Region' on type 'String' not found.] Microsoft.VisualBasic.CompilerServices.Container.GetMembers(String& MemberName, Boolean ReportErrors) +509081 Microsoft.VisualBasic.CompilerServices.NewLateBinding.LateGet(Object Instance, Type Type, String MemberName, Object[] Arguments, String[] ArgumentNames, Type[] TypeArguments, Boolean[] CopyBack) +222 BT.Handlers.RegionsAutoComplete.ProcessRequest(HttpContext context) in E:\Projects\businesstrader\App_Code\Handlers\RegionsAutoComplete.vb:35 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +181 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75 Can anyone tell me what I'm doing wrong?

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  • Linq to SQL EntitySet Binding the MVVM way

    - by Savvas Sopiadis
    Hi everybody! In a WPF application i'm using LINQ to SQL classes (created by SQL Metal, thus implementing POCOs). Let's assume i have a table User and a Table Pictures. These pictures are actually created from one picture, the difference between them may be the size, coloring,... So every user may has more than one Pictures, so the association is 1:N (User:Pictures). My problems: a) how do i bind, in a MVVM manner, a picture control to one picture (i will take one specific picture) in the EntitySet, to show it up? b) everytime a user changes her picture the whole EntitySet should be thrown away and the newly created Picture(s) should be a added. Is this the correct way? e.g. //create the 1st piture object UserPicture1 = new UserPicture(); UserPicture1.Description = "... some description.. "; USerPicture1.Image = imgBytes; //array of bytes //create the 2nd piture object UserPicture2 = new UserPicture(); UserPicture2.Description = "... another description.. "; UserPicture2.Image = DoSomethingWithPreviousImg(imgBytes); //array of bytes //Assuming that the entityset is called Pictures //add these pictures to the corresponding user User.Pictures.Add(UserPicture1); User.Pictures.Add(UserPicture2); //save changes datacontext.Save() Thanks in advance

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  • Update XML element with LINQ to XML in VB.NET

    - by Bayonian
    Hi, I'm trying to update an element in the XML document below: Here's the code: Dim xmldoc As XDocument = XDocument.Load(theXMLSource1) Dim ql As XElement = (From ls In xmldoc.Elements("LabService") _ Where CType(ls.Element("ServiceType"), String).Equals("Scan") _ Select ls.Element("Price")).FirstOrDefault ql.SetValue("23") xmldoc.Save(theXMLSource1) Here's the XML file: <?xml version="1.0" encoding="utf-8"?> <!--Test XML with LINQ to XML--> <LabSerivceInfo> <LabService> <ServiceType>Copy</ServiceType> <Price>1</Price> </LabService> <LabService> <ServiceType>PrintBlackAndWhite</ServiceType> <Price>2</Price> </LabService> </LabSerivceInfo> But, I got this error message: Object reference not set to an instance of an object. Exception Details: System.NullReferenceException: Object reference not set to an instance of an object. Error line:ql.SetValue("23") Can you show me what the problem is? Thank you.

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  • C# PredicateBuilder Entities: The parameter 'f' was not bound in the specified LINQ to Entities quer

    - by Neothor
    I needed to build a dynamic filter and I wanted to keep using entities. Because of this reason I wanted to use the PredicateBuilder from albahari. I created the following code: var invoerDatums = PredicateBuilder.True<OnderzoeksVragen>(); var inner = PredicateBuilder.False<OnderzoeksVragen>(); foreach (var filter in set.RapportInvoerFilter.ToList()) { if(filter.IsDate) { var date = DateTime.Parse(filter.Waarde); invoerDatums = invoerDatums.Or(o => o.Van >= date && o.Tot <= date); } else { string temp = filter.Waarde; inner = inner.Or(o => o.OnderzoekType == temp); } } invoerDatums = invoerDatums.And(inner); var onderzoeksVragen = entities.OnderzoeksVragen .AsExpandable() .Where(invoerDatums) .ToList(); When I ran the code there was only 1 filter which wasn't a date filter. So only the inner predicate was filled. When the predicate was executed I got the following error. The parameter 'f' was not bound in the specified LINQ to Entities query expression. While searching for an answer I found the following page. But this is already implemented in the LINQKit. Does anyone else experienced this error and know how to solve it?

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  • Join 3 tables in 1 LINQ-EF

    - by user100161
    I have to fill warehouse table cOrders with program using Ado.NET EF. I have SQL command but i don't know how to do this with LINQ. static void Main(string[] args) { var SPcontex = new PI_NorthwindSPEntities(); var contex = new NorthwindEntities(); dCustomers dimenzijaCustomers = new dCustomers(); dDatum dimenzijaDatum = new dDatum(); ... CREATE TABLE PoslovnaInteligencija.dbo.cOrders( cOrdersID int PRIMARY KEY IDENTITY(1,1), OrderID int NOT NULL, dCustomersID int FOREIGN KEY REFERENCES PoslovnaInteligencija.dbo.dCustomers(dCustomersID), dEmployeesID int FOREIGN KEY REFERENCES PoslovnaInteligencija.dbo.dEmployees(dEmployeesID), OrderDateID int FOREIGN KEY REFERENCES PoslovnaInteligencija.dbo.dDatum(sifDatum), RequiredDateID int FOREIGN KEY REFERENCES PoslovnaInteligencija.dbo.dDatum(sifDatum), ShippedDateID int FOREIGN KEY REFERENCES PoslovnaInteligencija.dbo.dDatum(sifDatum), dShippersID int FOREIGN KEY REFERENCES PoslovnaInteligencija.dbo.dShippers(dShippersID), dShipID int FOREIGN KEY REFERENCES PoslovnaInteligencija.dbo.dShip(dShipID), Freight money, WaitingDay int ) INSERT INTO PoslovnaInteligencija.dbo.cOrders (OrderID, dCustomersID, dEmployeesID, OrderDateID, RequiredDateID, dShippersID, dShipID, Freight, ShippedDateID, WaitingDay) SELECT OrderID, dc.dCustomersID, de.dEmployeesID, orderD.sifDatum, requiredD.sifDatum, dShippersID, ds.dShipID, Freight, ShippedDateID=CASE WHEN (ShippedDate IS NULL) THEN -1 ELSE shippedD.sifDatum END, WaitingDay=CASE WHEN (shippedD.sifDatum - orderD.sifDatum) IS NULL THEN -1 ELSE shippedD.sifDatum - orderD.sifDatum END FROM PoslovnaInteligencija.dbo.dShippers AS s, PoslovnaInteligencija.dbo.dCustomers AS dc, PoslovnaInteligencija.dbo.dEmployees AS de, PoslovnaInteligencija.dbo.dShip AS ds,PoslovnaInteligencija.dbo.dDatum AS orderD, PoslovnaInteligencija.dbo.dDatum AS requiredD, PoslovnaInteligencija.dbo.Orders AS o LEFT OUTER JOIN PoslovnaInteligencija.dbo.dDatum AS shippedD ON shippedD.datum=DATEADD(dd, 0, DATEDIFF(dd, 0, o.ShippedDate)) WHERE o.ShipVia=s.ShipperID AND dc.CustomerID=o.CustomerID AND de.EmployeeID=o.EmployeeID AND ds.ShipName=o.ShipName AND orderD.datum=DATEADD(dd, 0, DATEDIFF(dd, 0, o.OrderDate)) AND requiredD.datum=DATEADD(dd, 0, DATEDIFF(dd, 0, o.RequiredDate));

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  • LINQ to DataSet Dataclass assignment question

    - by Overhed
    Hi all, I'm working on a Silverlight project trying to access a database using LINQ To DataSet and then sending data over to Silverlight via .ASMX web service. I've defined my DataSet using the Server Explorer tool (dragging and dropping all the different tables that I'm interested in). The DataSet is able to access the server and database with no issues. Below is code from one of my Web Methods: public List<ClassSpecification> getSpecifications() { DataSet2TableAdapters.SpecificationTableAdapter Sta = new DataSet2TableAdapters.SpecificationTableAdapter(); return (from Spec in Sta.GetData().AsEnumerable() select new ClassSpecification() { Specification = Spec.Field<String>("Specification"), SpecificationType = Spec.Field<string>("SpecificationType"), StatusChange = Spec.Field<DateTime>("StatusChange"), Spec = Spec.Field<int>("Spec") }).ToList<ClassSpecification>(); } I created a "ClassSpecification" data class which is going to contain my data and it has all the table fields as properties. My question is, is there a quicker way of doing the assignment than what is shown here? There are actually about 10 more fields, and I would imagine that since my DataSet knows my table definition, that I would have a quicker way of doing the assignment than going field by field. I tried just "select new ClassSpecification()).ToList Any help would be greatly appreciated.

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  • LINQ 2 SQL: Partial Classes

    - by Refracted Paladin
    I need to set the ConnectionString for my DataContext's based on an AppSetting. I am trying to do this by creating a Partial Class for each DataContext. The below is what I have so far and I am wondering if I am overlooking something? Specifically, am I dealing with my DataContext's correctly(disposing, staleness, etc)? Doing it this way will I have issues with Updates and Inserts? Is the file BLLAspnetdb.cs useful or neccessary in the least or should all of that be in the generated partial class AspnetdbDataContext file? In short, is this an acceptable structure or will this cause me issues as I elaborate it? dbml File Name = Aspnetdb.dbml Partial Class File Name = Aspnetdb.cs partial class AspnetdbDataContext { public static bool IsDisconnectedUser { get { return Convert.ToBoolean(ConfigurationManager.AppSettings["IsDisconnectedUser"]) == true; } } public static AspnetdbDataContext New { get { var cs = IsDisconnectedUser ? Settings.Default.Central_aspnetdbConnectionString : Settings.Default.aspnetdbConnectionString; return new AspnetdbDataContext(cs); } } } My Created File Name = BLLAspnetdb.cs public class BLLAspnetdb { public static IList WorkerList(Guid userID) { var DB = AspnetdbDataContext.New; var workers = from user in DB.tblDemographics where user.UserID == userID select new { user.FirstName, user.LastName, user.Phone }; IList theWorkers = workers.ToList(); return theWorkers; } public static String NurseName(Guid? userID) { var DB = AspnetdbDataContext.New; var nurseName = from demographic in DB.tblDemographics where demographic.UserID == userID select demographic.FirstName +" " + demographic.LastName; return nurseName.SingleOrDefault(); } public static String SocialWorkerName(Guid? userID) { var DB = AspnetdbDataContext.New; var swName = from demographic in DB.tblDemographics where demographic.UserID == userID select demographic.FirstName + " " + demographic.LastName; return swName.SingleOrDefault(); } } see this previous question and the accepted answer for background on how I got to here... switch-connectionstrings-between-local-and-remote-with-linq-to-sql

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  • Search XDocument with LINQ with out knowing the Namespace

    - by BarDev
    Is there a way to search a XDocument without knowing the Namespace. I have a process that logs all soap requests and encrypts the sensitive data. I want to find any elements based on name. Something like, give me all elements where the name is CreditCard. I don't care what the namespace is. My problem seems to be with LINQ and requiring a xml namespace. I have other processes that retrieve values from XML, but I know the namespace for these other process. XDocument xDocument = XDocument.Load(@"C:\temp\Packet.xml"); XNamespace xNamespace = "http://CompanyName.AppName.Service.Contracts"; var elements = xDocument.Root.DescendantsAndSelf().Elements().Where(d = d.Name == xNamespace + "CreditCardNumber"); But what I really want, is to have the ability to search xml without knowing about namespaces, something like this: XDocument xDocument = XDocument.Load(@"C:\temp\Packet.xml"); var elements = xDocument.Root.DescendantsAndSelf().Elements().Where(d = d.Name == "CreditCardNumber") But of course this will not work be cause I do no have a namespace. BarDev

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  • Delete record in Linq to Sql

    - by Anders Svensson
    I have Linq2Sql classes User, Page, and UserPage (from a junction table), i.e. a many-to-many relationship. I'm using a gridview to show all Users, with a dropdownlist in each row to show the Pages visited by each user. Now I want to be able to delete records through the gridview, so I have added a delete button in the gridview by setting "Enable deleting" on it. Then I tried to use the RowDeleting event to specify how to delete the records since it doesn't work by default. And because its a relationship I know I need to delete the related records in the junction table before deleting the user record itself, so I added this in the RowDeleting event: protected void GridView2_RowDeleting(object sender, GridViewDeleteEventArgs e) { int id = (int)((DataKey)GridView2.DataKeys[e.RowIndex]).Value; UserPageDBDataContext context = new UserPageDBDataContext(); var userPages = from userPage in context.UserPages where userPage.User.UserID == id select userPage; foreach (var userPage in userPages) context.UserPages.DeleteOnSubmit(userPage); context.SubmitChanges(); var user = context.Users.Single(u => u.UserID == id); context.Users.DeleteOnSubmit(user); context.SubmitChanges(); } This actually seems to delete records, because the record with the id in question does indeed disappear, but strangely, a new record seems to be added at the end...! So, say I have 3 records in the gridview: 1 Jack stackoverflow.com 2 Betty stackoverflow.com/questions 3 Joe stackoverflow.com/whatever Now, if I try to delete user 1 (Jack), record number 1 will indeed disappear in the gridview, but the same record will appear at the end with a new id: 2 Jack stackoverflow.com 3 Betty stackoverflow.com/questions 4 Joe stackoverflow.com/whatever I have tried searching on how to delete records using Linq, and I believe I'm doing exacly as the examples I have read (e.g. the second example here: http://msdn.microsoft.com/en-us/library/Bb386925%28v=VS.100%29.aspx). I have read that you can also set cascade delete on the relationship in the database, but I wanted to do it this way in code, as your supposed to be able to. So what am I doing wrong?

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  • Dynamic where clause using Linq to SQL in a join query in a MVC application

    - by jhoefnagels
    Dear .Net Linq experts, I am looking for a way to query for products in a catalog using filters on properties which have been assigned to the product based on the category to which the product belongs. So I have the following entities involved: Products -Id -CategoryId Categories [Id] Properties [Id, CategoryId] PropertyValues [Id, PropertyId] ProductProperties [ProductId, PropertyValueId] When I ad a product to the catalog, multiple ProductProperties will be added based on the category and I would like to be able to filter all products from a category by selecting values for one or more properties. I will gather all filters, which I will hold in a list, by reading the URL. Now it is time to actually get the products based on multiple properties and I have been trying to find the right strategy but untill now it does not really work. Is there a way to make this work without writing SQL? I was trying something like this: productsInCategory = ProductRepository.Where(p => p.Category.Name == category); foreach (PropertyFilter pf in filterList) { productsInCategory = (from product in productsInCategory join pp in ProductPropertyRepository on product.Id equals pp.ProductId where pp.PropertyValueId == pf.ValueId select product); }

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  • Linq Query to Update Nested Array Items?

    - by Brett
    I have an object structure generated from xsd.exe. Roughly, it consists of 3 nested arrays: protocols, sources and reports. The xml looks like this: <protocols> <protocol> <source> <report /> <report /> </source> <source> <report /> <report /> </source> </protocol> <!-- more protocols --> </protocols> I need to update a single "Report" within the data structure. A brute force algorithm is shown below. I know that this could be done using XDocument and Linq, but I'd prefer to update the data structure and then serialize the structure back to disk. Thoughts? Brett bool updated = false; foreach (ProtocolsProtocol protocol in protocols.Protocol) { if (updated) break; foreach (ProtocolsProtocolSource source in protocol.Source) { if (updated) break; for (int i = 0; i < source.Report.Length; i++) { ProtocolsProtocolSourceReport currentReport = source.Report[i]; if (currentReport.Id == report.Id) { currentReport.Attribute1 = report.Attribute1; currentReport.Attribute2 = report.Attribute2; updated = true; break; } } } }

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  • Linq to XML: create an anonymous object with element attributes and values

    - by Phil Scholtes
    I'm new to Linq and I'm trying to query a XML document to find a list of account managers for a particular user. (I realize it might make more sense to put this in a database or something else, but this scenario calls for a XML document). <user emailAddress='[email protected]'> <accountManager department='Customer Service' title='Manager'>[email protected]</accountManager> <accountManager department='Sales' title='Account Manager'>[email protected]</accountManager> <accountManager department='Sales' title='Account Manager'>[email protected]</accountManager> </user> I trying to create a list of objects (anonymous type?) with properties consisting of both XElement attributes (department, title) and values (email). I know that I can get either of the two, but my problem is selecting both. Here is what I'm trying: var managers = _xDoc.Root.Descendants("user") .Where(d => d.Attribute("emailAddress").Value == "[email protected]") .SelectMany(u => u.Descendants("accountManager").Select(a => a.Value)); foreach (var manager in managers) { //do stuff } I can get at a.Value and a.Attribute but I can't figure out how to get both and store them in an object. I have a feeling it would wind up looking something like: select new { department = u.Attribute("department").Value, title = u.Attribute("title").Value, email = u.Value };

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  • C# - Help with LINQ

    - by cmaduro
    I need to check if a certain property exists within a class. Please refer to the LINQ query in question. For the life of me I cannot make the compiler happy. class Program { static void Main(string[] args) { ModuleManager m = new ModuleManager(); IModule module = m.FindModuleForView(typeof(HomeView)); Console.WriteLine(module.GetType().ToString()); Console.ReadLine(); } } public class ModuleManager { [ImportMany] public IEnumerable<Lazy<IModule>> Modules { get; set; } [ImportMany] public IEnumerable<Lazy<View>> Views { get; set; } public ModuleManager() { //An aggregate catalog that combines multiple catalogs var catalog = new AggregateCatalog(); //Adds all the parts found in the same assembly as the Program class catalog.Catalogs.Add(new AssemblyCatalog(typeof(Program).Assembly)); //Create the CompositionContainer with the parts in the catalog _container = new CompositionContainer(catalog); //Fill the imports of this object try { this._container.ComposeParts(this); } catch (CompositionException compositionException) { Console.WriteLine(compositionException.ToString()); } } public IModule FindModuleForView(Type view) { //THIS IS THE PROBLEM var module = from m in Modules where ( from p in m.Value.GetType().GetProperties() where p.GetType().Equals(view) select p ) select m; } public CompositionContainer _container { get; set; } } public interface IModule { } [Export] public class HomeModule : IModule { public HomeModule() { } [Export] public HomeView MyHomeView { get { return new HomeView(); } set { } } } public class HomeView : View { } public class View { }

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  • Passing a LINQ DataRow Reference in a GridView's ItemTemplate

    - by Bob Kaufman
    Given the following GridView: <asp:GridView runat="server" ID="GridView1" AutoGenerateColumns="false" DataKeyNames="UniqueID" OnSelectedIndexChanging="GridView1_SelectedIndexChanging" > <Columns> <asp:BoundField HeaderText="Remarks" DataField="Remarks" /> <asp:TemplateField HeaderText="Listing"> <ItemTemplate> <%# ShowListingTitle( ( ( System.Data.DataRowView ) ( Container.DataItem ) ).Row ) %> </ItemTemplate> </asp:TemplateField> <asp:BoundField HeaderText="Amount" DataField="Amount" DataFormatString="{0:C}" /> </Columns> </asp:GridView> which refers to the following code-behind method: protected String ShowListingTitle( DataRow row ) { Listing listing = ( Listing ) row; return NicelyFormattedString( listing.field1, listing.field2, ... ); } The cast from DataRow to Listing is failing (cannot convert from DataRow to Listing) I'm certain the problem lies in what I'm passing from within the ItemTemplate, which is simply not the right reference to the current record from the LINQ to SQL data set that I've created, which looks like this: private void PopulateGrid() { using ( MyDataContext context = new MyDataContext() ) { IQueryable < Listing > listings = from l in context.Listings where l.AccountID == myAccountID select l; GridView1.DataSource = listings; GridView1.DataBind(); } }

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  • Linq to SQL with INSTEAD OF Trigger and an Identity Column

    - by Bob Horn
    I need to use the clock on my SQL Server to write a time to one of my tables, so I thought I'd just use GETDATE(). The problem is that I'm getting an error because of my INSTEAD OF trigger. Is there a way to set one column to GETDATE() when another column is an identity column? This is the Linq-to-SQL: internal void LogProcessPoint(WorkflowCreated workflowCreated, int processCode) { ProcessLoggingRecord processLoggingRecord = new ProcessLoggingRecord() { ProcessCode = processCode, SubId = workflowCreated.SubId, EventTime = DateTime.Now // I don't care what this is. SQL Server will use GETDATE() instead. }; this.Database.Add<ProcessLoggingRecord>(processLoggingRecord); } This is the table. EventTime is what I want to have as GETDATE(). I don't want the column to be null. And here is the trigger: ALTER TRIGGER [Master].[ProcessLoggingEventTimeTrigger] ON [Master].[ProcessLogging] INSTEAD OF INSERT AS BEGIN SET NOCOUNT ON; SET IDENTITY_INSERT [Master].[ProcessLogging] ON; INSERT INTO ProcessLogging (ProcessLoggingId, ProcessCode, SubId, EventTime, LastModifiedUser) SELECT ProcessLoggingId, ProcessCode, SubId, GETDATE(), LastModifiedUser FROM inserted SET IDENTITY_INSERT [Master].[ProcessLogging] OFF; END Without getting into all of the variations I've tried, this last attempt produces this error: InvalidOperationException Member AutoSync failure. For members to be AutoSynced after insert, the type must either have an auto-generated identity, or a key that is not modified by the database after insert. I could remove EventTime from my entity, but I don't want to do that. If it was gone though, then it would be NULL during the INSERT and GETDATE() would be used. Is there a way that I can simply use GETDATE() on the EventTime column for INSERTs? Note: I do not want to use C#'s DateTime.Now for two reasons: 1. One of these inserts is generated by SQL Server itself (from another stored procedure) 2. Times can be different on different machines, and I'd like to know exactly how fast my processes are happening.

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  • Using LINQ in generic collections

    - by Hugo S Ferreira
    Hi, Please consider the following snippet from an implementation of the Interpreter pattern: public override object Execute(Interpreter interpreter, object ctx) { var list = ctx as IEnumerable<string>; return (list != null) ? list.FirstOrDefault() : null; } What about if I want to use the same function for integers? public override object Execute(Interpreter interpreter, object ctx) { var list = ctx as IEnumerable<string>; if (list != null) return list.FirstOrDefault(); var list = ctx as IEnumerable<int>; return (list != null) ? list.FirstOrDefault() : null; } What I wanted was something like: public override object Execute(Interpreter interpreter, object ctx) { var list = ctx as IEnumerable; return (list != null) ? list.FirstOrDefault() : null; } But Linq doesn't act on IEnumerables. Instead, to get to this solution, I would be forced to write something like: public override object Execute(Interpreter interpreter, object ctx) { var list = ctx as IEnumerable; if (list != null) foreach(var i in list) { yield return i; return; } return null; } Or use a generic method: public override T Execute<T>(Interpreter interpreter, object ctx) { var list = ctx as IEnumerable<T>; return (list != null) ? list.FirstOrDefault() : null; } Which would break the Interpreter pattern (as it was implemented in this system). Covariance would also fail (at least in C#3), though would it work, it would be the exact behavior I wanted: public override object Execute(Interpreter interpreter, object ctx) { var list = ctx as IEnumerable<object>; return (list != null) ? list.FirstOrDefault() : null; } So, my question is: what's the best way to achieve the intended behavior? Thanks :-)

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  • LINQ-To-SQL and Mapping Table Deletions

    - by Jake
    I have a many-to-many relationship between two tables, let's say Friends and Foods. If a friend likes a food I stick a row into the FriendsFoods table, like this: ID Friend Food 1 'Tom' 'Pizza' FriendsFoods has a Primary Key 'ID', and two non-null foreign keys 'Friend' and 'Food' to the 'Friends' and 'Foods' tables, respectively. Now suppose I have a Friend tom .NET object corresponding to 'Tom', and Tom no longer likes pizza (what is wrong with him?) FriendsFoods ff = tblFriendsFoods.Where(x => x.Friend.Name == 'Tom' && x.Food.Name == 'Pizza').Single(); tom.FriendsFoods.Remove(ff); pizza.FriendsFoods.Remove(ff); If I try to SubmitChanges() on the DataContext, I get an exception because it attempts to insert a null into the Friend and Food columns in the FriendsFoods table. I'm sure I can put together some kind of convoluted logic to track changes to the FriendsFoods table, intercept SubmitChanges() calls, etc to try and get this to work the way I want, but is there a nice, clean way to remove a Many-To-Many relationship with LINQ-To-SQL?

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  • Linq to XML Document Traversal

    - by Perpetualcoder
    I have an xml document like this: <?xml version="1.0" encoding="utf-8" ?> <demographics> <country id="1" value="USA"> <state id ="1" value="California"> <city>Long Beach</city> <city>Los Angeles</city> <city>San Diego</city> </state> <state id ="2" value="Arizona"> <city>Tucson</city> <city>Phoenix</city> <city>Tempe</city> </state> </country> <country id="2" value="Mexico"> <state id ="1" value="Baja California"> <city>Tijuana</city> <city>Rosarito</city> </state> </country> </demographics> How do I setup LINQ queries for doing things like: 1. Get All Countries 2. Get All States in a Country 3. Get All Cities inside a state of a paricular country ? I gave it a try and I am kind of confused when to use Elements["NodeName"] and Descendants etc. I know I am not the brightest XML guy around. Is the format of the XML file even correct for simple traversal?

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  • Quering container with Linq + group by ?

    - by Prix
    public class ItemList { public int GuID { get; set; } public int ItemID { get; set; } public string Name { get; set; } public entityType Status { get; set; } public class Waypoint { public int Zone { get; set; } public int SubID { get; set; } public int Heading { get; set; } public float PosX { get; set; } public float PosY { get; set; } public float PosZ { get; set; } } public List<Waypoint> Routes = new List<Waypoint>(); } I have a list of items using the above class and now I need to group it by ItemID and join the first entry of Routes of each iqual ItemID. So for example, let's say on my list I have: GUID ItemID ListOfRoutes 1 23 first entry only 2 23 first entry only 3 23 first entry only 4 23 first entry only 5 23 first entry only 6 23 first entry only 7 23 first entry only Means I have to group entries 1 to 7 as 1 Item with all the Routes entries. So I would have one ItemID 23 with 7 Routes on it where those routes are the first element of that given GUID Routes List. My question is if it is possible using LINQ to make a statment to do something like that this: var query = from ItemList entry in myList where status.Contains(entry.Status) group entry by entry.ItemID into result select new { items = new { ID = entry.ItemID, Name = entry.Name }, routes = from ItemList m in entry group m.Routes.FirstOrDefault() by n.NpcID into m2 }; So basicly I would have list of unique IDS information with a inner list of all the first entry of each GUID route that had the same ItemID.

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  • Error when calling SQL SP via LINQ

    - by PaulC
    Newbie problem: I have a SQL SP with ten parameters (eight input, two output) but when I attempt to call it via LINQ from code I get the following error message: "The best overloaded method match for 'DataClassesDataContext.ST_CR_CREATE_CASE_BASIS(string, string, string, string, System.DateTime?, string, string, string, ref int?, ref int?)' has some invalid arguments". The params with ? appear to be unrecognized, but I'm baffled: the data types match the SQL types, the number of parameters match, the other parmeters don't exhibit the same behaviour. Can anyone tell me what's going on? Thanks in advance. -- SQL SP: create procedure ST_CR_CREATE_CASE_BASIS @p_Pers_No nvarchar (50), @p_Subject nvarchar (255), @p_RQ_XML nvarchar(max), @p_RQ_XSL nvarchar(max), @p_Date_Submit smalldatetime, @p_User_ID_Submit nvarchar (255), @p_RQ_Status nvarchar (50), @p_User_ID_OnBehalf nvarchar (255), @p_Case_Number int output, @p_RQ_ID int output as begin -- ... etc.; the SP works fine when called from SSMS The code-behind proc from the aspx page looks like this: protected void cmdSubmit_Click(object sender, EventArgs e) { using (DataClassesDataContext vDataCont = new DataClassesDataContext()) { Int32 vNewCaseNr; Int32 vNewReqNr; DateTime vNow = System.DateTime.Now; vDataCont.ST_CR_CREATE_CASE_BASIS("101", "Test Subject Late Wed", null, null, vNow , "101", "1", "101", ref vNewCaseNr, vNewReqNr); } }

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