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  • Efficient retrieval of lists over WebServices

    - by Chris
    I have a WCF WebService that uses LINQ and EF to connect to an SQL database. I have an ASP.NET MVC front end that collects its data from the webservice. It currently has functions such as List<Customer> GetCustomers(); As the number of customers increases massively the amount of data being passed increases also reducing efficiency. What is the best way to "page data" across WebServices etc. My current idea is to implement a crude paging system such as List<Customer> GetCustomers(int start, int length); This, however, means I would have to replicate such code for all functions returning List types. It is unfortunate that I cannot use LINQ as it would be much nicer. Does anyone have any advice or ideas of patterns to implement that would be "as nice as possible" Thanks

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  • DataContext Doesn't Exist in Dynamic Data Project?

    - by davemackey
    This is really annoying...and I know it is something extremely simple... 1. I create a new Dynamic Data project. 2. I add a LINQ-to-SQL class and drag and drop some tables onto the class. 3. I open the global.asax.vb and uncomment the line: DefaultModel.RegisterContext(GetType(YourDataContext), New ContextConfiguration() With {.ScaffoldAllTables = True}) I remove YourDataContext and replace it with the DataContext from my LINQ-to-SQL class: DefaultModel.RegisterContext(GetType(NorthwindDataContext), New ContextConfiguration() With {.ScaffoldAllTables = True}) I then try to debug/build/etc. and receive the following error: Type 'NorthwindDataContext' is not defined Why is it not defined? It seems like its not recognizing I created the DBML file.

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  • Getting \ building latest NHibernate build

    - by Alex Yakunin
    I'd like to get the latest NHibernate build or build it by my own. The build available at SourceForge is dated by Nov 2009, although I see there was a lot of activity later, especially related to LINQ development. So what is the best option? I can: Get the latest source code and try to build it. Are there any instructions for this? Get one of latest builds shared by someone else. Are there any people maintaining such builds? Please note, that I'm not interested in 8-month old builds - I need the latest code for tests (LINQ, performance). I know there is a similar question, but it looks like top answers there are outdated.

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  • InvalidArgument=Value of '3' is not valid for 'rowIndex'

    - by Devendra Dwivedi
    Hi all This is my code It is working for if 1 terminal that is having 3 services but it is not working for more than 3 services when I do then I have got following error message: InvalidArgument=Value of '3' is not valid for 'rowIndex' I have so tired to find this problem but couldn't get any solutions. Anybody please help me. MySqlCommand command = new MySqlCommand("VTerminalsLoad");//Procedure MySqlDataAdapter terminalAdapter = this.Database.ExecuteCommand(command); terminalAdapter.Fill(dataSet, "Terminals"); command = new MySqlCommand("VTServicesLoad");//Procedure command.Parameters.Add(new MySqlParameter("pVesselID", 1)); MySqlDataAdapter serviceAdapter = this.Database.ExecuteCommand(command);//Return Adaptor serviceAdapter.Fill(dataSet, "Services"); DataColumn[] parentColumns = { dataSet.Tables[0].Columns["SerialNo"], dataSet.Tables[0].Columns["VesselID"], dataSet.Tables[0].Columns["TerminalID"] }; DataColumn[] childColumns = { dataSet.Tables[1].Columns["SerialNo"], dataSet.Tables[1].Columns["VesselID"], dataSet.Tables[1].Columns["TerminalID"] }; DataRelation relationTS = new DataRelation("TerminalsServices", parentColumns, childColumns); dataSet.Relations.Add(relationTS); //Parent Table ListTerminal.DataSource = dataSet; //ListTerminal Parent datagridview ListTerminal.DataMember = "Terminals"; //Child Table ListServices.DataSource = dataSet;// ListServices Child datagridview ListServices.DataMember = "Terminals.TerminalsServices";

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  • Entity Framework many-to-many using VB.Net Lambda

    - by bgs264
    Hello, I'm a newbie to StackOverflow so please be kind ;) I'm using Entity Framework in Visual Studio 2010 Beta 2 (.NET framework 4.0 Beta 2). I have created an entity framework .edmx model from my database and I have a handful of many-to-many relationships. A trivial example of my database schema is Roles (ID, Name, Active) Members (ID, DateOfBirth, DateCreated) RoleMembership(RoleID, MemberID) I am now writing the custom role provider (Inheriting System.Configuration.Provider.RoleProvider) and have come to write the implementation of IsUserInRole(username, roleName). The LINQ-to-Entity queries which I wrote, when SQL-Profiled, all produced CROSS JOIN statements when what I want is for them to INNER JOIN. Dim query = From m In dc.Members From r In dc.Roles Where m.ID = 100 And r.Name = "Member" Select m My problem is almost exactly described here: http://stackoverflow.com/questions/553918/entity-framework-and-many-to-many-queries-unusable I'm sure that the solution presented there works well, but whilst I studied Java at uni and I can mostly understand C# I cannot understand this Lambda syntax provided and I need to get a similar example in VB. I've looked around the web for the best part of half a day but I'm not closer to my answer. So please can somebody advise how, in VB, I can construct a LINQ statement which would do this equivalent in SQL: SELECT rm.RoleID FROM RoleMembership rm INNER JOIN Roles r ON r.ID = rm.RoleID INNER JOIN Members m ON m.ID = rm.MemberID WHERE r.Name = 'Member' AND m.ID = 101 I would use this query to see if Member 101 is in Role 3. (I appreciate I probably don't need the join to the Members table in SQL but I imagine in LINQ I'd need to bring in the Member object?) UPDATE: I'm a bit closer by using multiple methods: Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load Dim count As Integer Using dc As New CBLModel.CBLEntities Dim persons = dc.Members.Where(AddressOf myTest) count = persons.Count End Using System.Diagnostics.Debugger.Break() End Sub Function myTest(ByVal m As Member) As Boolean Return m.ID = "100" AndAlso m.Roles.Select(AddressOf myRoleTest).Count > 0 End Function Function myRoleTest(ByVal r As Role) As Boolean Return r.Name = "Member" End Function SQL Profiler shows this: SQL:BatchStarting SELECT [Extent1].[ID] AS [ID], ... (all columns from Members snipped for brevity) ... FROM [dbo].[Members] AS [Extent1] RPC:Completed exec sp_executesql N'SELECT [Extent2].[ID] AS [ID], [Extent2].[Name] AS [Name], [Extent2].[Active] AS [Active] FROM [dbo].[RoleMembership] AS [Extent1] INNER JOIN [dbo].[Roles] AS [Extent2] ON [Extent1].[RoleID] = [Extent2].[ID] WHERE [Extent1].[MemberID] = @EntityKeyValue1',N'@EntityKeyValue1 int',@EntityKeyValue1=100 SQL:BatchCompleted SELECT [Extent1].[ID] AS [ID], ... (all columns from Members snipped for brevity) ... FROM [dbo].[Members] AS [Extent1] I'm not certain why it is using sp_execsql for the inner join statement and why it's still running a select to select ALL members though. Thanks. UPDATE 2 I've written it by turning the above "multiple methods" into lambda expressions then all into one query, like this: Dim allIDs As String = String.Empty Using dc As New CBLModel.CBLEntities For Each retM In dc.Members.Where(Function(m As Member) m.ID = 100 AndAlso m.Roles.Select(Function(r As Role) r.Name = "Doctor").Count > 0) allIDs &= retM.ID.ToString & ";" Next End Using But it doesn't seem to work: "Doctor" is not a role that exists, I just put it in there for testing purposes, yet "allIDs" still gets set to "100;" The SQL in SQL Profiler this time looks like this: SELECT [Project1].* FROM ( SELECT [Extent1].*, (SELECT COUNT(1) AS [A1] FROM [dbo].[RoleMembership] AS [Extent2] WHERE [Extent1].[ID] = [Extent2].[MemberID]) AS [C1] FROM [dbo].[Members] AS [Extent1] ) AS [Project1] WHERE (100 = [Project1].[ID]) AND ([Project1].[C1] > 0) For brevity I turned the list of all the columns from the Members table into * As you can see it's just ignoring the "Role" query... :/

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  • C# LINQ Where Predicate Type Arguments

    - by blu
    I have an XElement with values for mock data. I have an expression to query the xml: Expression<Func<XElement, bool>> simpleXmlFunction = b => int.Parse(b.Element("FooId").Value) == 12; used in: var simpleXml = xml.Elements("Foo").Where(simpleXmlFunction).First(); The design time error is: The type arguments for method 'System.Linq.Enumerable.Where(System.Collections.Generic.IEnumerable, System.Func)' cannot be inferred from the usage. Try specifying the type arguments explicitly' The delegate supplied to Where should take in an XElement and return a bool, marking if the item matches the query, I am not sure how to add anything more to the delegate or the where clause to mark the type. Also, the parallel method for the real function against the Entity Framework does not have this issue. What is not correct with the LINQ-to-XML version?

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  • Mailer issue, PHP values do not change

    - by Roland
    I have a script that runs once every month and send out stats to clients, now the stats are displayed in normal text and in the shape of a Pie Graph, now if I run the script mannually from the command line all info on the graphs are correct, but when the cron job executes the script the values for the first client are displaying on the graphs of all clients. but the text is correct. I'm using domDocument to build the HTML and PHPMailer to send out the email with the Graphs embedded into the mail also use pChart to generate the Graph My code that generates the PIE graph is below include_once "pChart.1.26e/pChart/pData.class"; include_once "pChart.1.26e/pChart/pChart.class"; // Dataset definition unset($DataSet); $DataSet = new pData; $DataSet->AddPoint(array($data['total_clicks'],$remaining),"Serie1"); if($remaining < 0){ $DataSet->AddPoint(array("Clicks delivered todate","Clicks remaining = 0"),"Serie2"); }else{ $DataSet->AddPoint(array("Clicks delivered todate","Clicks remaining"),"Serie2"); } $DataSet->AddAllSeries(); $DataSet->SetAbsciseLabelSerie("Serie2"); // Initialise the graph $pie = new pChart(492,292); $pie->drawBackground(255,255,254); $pie->LineWidth = 1.1; $pie->Values = 2; // $pie->drawRoundedRectangle(5,5,375,195,5,230,230,230); //$pie->drawRectangle(0,0,480,288,169,169,169); $pie->drawRectangle(5,5,487,287,169,169,169); $pie->loadColorPalette('pChart.1.26e/color/tones-3.txt',','); // Draw the pie chart $pie->setFontProperties("pChart.1.26e/Fonts/calibrib.ttf",18); $pie->drawTitle(140,33,"Campaign Overview",0,0,0); $pie->setFontProperties("pChart.1.26e/Fonts/calibrib.ttf",11); $pie->drawTitle(343,125,"Total clicks : ".$total_clicks,0,0,0); $pie->setFontProperties("pChart.1.26e/Fonts/calibri.ttf",10); if($remaining < 0){ $pie->setFontProperties("pChart.1.26e/Fonts/calibrib.ttf",10); $pie->drawTitle(260,250,"Campaign over-delivered by ".substr($remaining,1)." clicks",205,53,53); $pie->setFontProperties("pChart.1.26e/Fonts/calibri.ttf",10); } $pie->drawPieLegend(328,140,$DataSet->GetData(),$DataSet->GetDataDescription(),255,255,255); $pie->drawPieGraph($DataSet->GetData(),$DataSet->GetDataDescription(),170,150,130,PIE_VALUE,FALSE,50,30,0); $pie->Render("generated/3dpie.png"); unset($pie); unset($DataSet); $mail->AddEmbeddedImage("/var/www/html/stats/generated/3dpie.png","5"); I just can't understand why this only happens when the cronjob runs?

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  • Would you use WCF Linq and JSON for an API

    - by Rico
    Ok Im building AN API but also wanting to have that API used by my own Application. I am pondering WCF, LinQ and JSON for my Webservices and Data and Silverlight for my application. I have a few questions. 1) would you recommend XML over JSON or Json over XML? a) is Json going to transfer and deserialize faster natively or is XML going to transfer and deserialize faster? 2) would Using LINQ hinder anyone connecting to my Service form PHP? 3) Would you recommend something different?

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  • DataSets and XML - The Simplistic Approach

    One of the first ways I learned how to read xml data from external data sources was by using a DataSet’s ReadXML function. This function takes file path for an XML document and then converts it to a Dataset. This functionality is great when you need a simple way to process an XML document.  In addition the DataSet object also offers a simple way to save data in an xml format by using the WriteXML function. This function saves the current data in the DataSet to an XML file to be used later. DataSet ds  = New DataSet();String filePath = “http://www.yourdomain.com/someData.xml”;String fileSavePath = “C:\Temp\Test.xml”//Read file for this locationds.readxml(filePath);//Save file to this locationds.writexml(fileSavePath); I have used the ReadXML function before when consuming data from external Rss feeds to display on one of my sites.  It allows me to quickly pull in data from external sites with little to no processing. Example site: MyCreditTech.com

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  • Listview of items from a object selected in another listview

    - by Ingó Vals
    Ok the title maybe a little confusing. I have a database with the table Companies wich has one-to-many relotionship with another table Divisions ( so each company can have many divisions ) and division will have many employees. I have a ListView of the companies. What I wan't is that when I choose a company from the ListView another ListView of divisions within that company appears below it. Then I pick a division and another listview of employees within that division appaers below that. You get the picture. Is there anyway to do this mostly inside the XAML code declaritively (sp?). I'm using linq so the Company entity objects have a property named Division wich if I understand linq correctly should include Division objects of the divisions connected to the company. So after getting all the companies and putting them as a itemsource to CompanyListView this is where I currently am. <ListView x:Name="CompanyListView" DisplayMemberPath="CompanyName" Grid.Row="0" Grid.Column="0" /> <ListView DataContext="{Binding ElementName=CompanyListView, Path=SelectedItem}" DisplayMemberPath="Division.DivisionName" Grid.Row="1" Grid.Column="0" /> I know I'm way off but I was hoping by putting something specific in the DataContext and DisplayMemberPath I could get this to work. If not then I have to capture the Id of the company I guess and capture a select event or something. Another issue but related is the in the seconde column besides the lisview I wan't to have a details/edit view for the selected item. So when only a company is selected details about that will appear then when a division under the company is picked It will go there instead, any ideas?

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  • XElement.Load("~/App_Data/file.xml") Could not find a part of the path

    - by mahdiahmadirad
    hi everybody, I am new in LINQtoXML. I want to use XElement.Load("") Method. but the compiler can't find my file. can you help me to write correct path for my XML file? Note that: I defined a Class in App_Code and I want to use the XML file data in one of methods and my XML file Located in App_Data. settings = XElement.Load("App_Data/AppSettings.xml"); i cant Use Request.ApplicationPath and Page.MapPath() or Server.MapPath() to get the physical path for my file because i am not in a class Inherited form Page class. Brief error Message: *Could not find a part of the path 'C:\Program Files\Microsoft Visual Studio 9.0\Common7\IDE\App_Data\AppSettings.xml'*. you see the path compiled is fully different from my project path(G:\MyProjects\ASP.net Projects\VistaComputer\Website\App_Data\AppSettings.xml) Full error Message is here: System.IO.DirectoryNotFoundException was unhandled by user code Message="Could not find a part of the path 'C:\\Program Files\\Microsoft Visual Studio 9.0\\Common7\\IDE\\App_Data\\AppSettings.xml'." Source="mscorlib" StackTrace: at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath) at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy) at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize) at System.Xml.XmlDownloadManager.GetStream(Uri uri, ICredentials credentials) at System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn) at System.Xml.XmlReader.Create(String inputUri, XmlReaderSettings settings, XmlParserContext inputContext) at System.Xml.XmlReader.Create(String inputUri, XmlReaderSettings settings) at System.Xml.Linq.XElement.Load(String uri, LoadOptions options) at System.Xml.Linq.XElement.Load(String uri) at ProductActions.Add(Int32 catId, String title, String price, String website, String shortDesc, String fullDesc, Boolean active, Boolean editorPick, String fileName, Stream image) in g:\MyProjects\ASP.net Projects\VistaComputer\Website\App_Code\ProductActions.cs:line 67 at CMS_Products_Operations.Button1_Click(Object sender, EventArgs e) in g:\MyProjects\ASP.net Projects\VistaComputer\Website\CMS\Products\Operations.aspx.cs:line 72 at System.Web.UI.WebControls.Button.OnClick(EventArgs e) at System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) at System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) InnerException:

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  • LinqToSql - Parallel - DataContext and Parallel

    - by Gregoire
    In .NET 4 and multicore environment, does the linq to sql datacontext object take advantage of the new parallels if we use DataLoadOptions.LoadWith? EDIT I know linq to sql does not parallelize ordinary queries. What I want to know is when we specify DataLoadOption.LoadWith, does it use parallelization to perform the match between each entity and its sub entities? Example: using(MyDataContext context = new MyDataContext()) { DataLaodOptions options =new DataLoadOptions(); options.LoadWith<Product>(p=>p.Category); return this.DataContext.Products.Where(p=>p.SomeCondition); } generates the following sql: Select Id,Name from Categories Select Id,Name, CategoryId from Products where p.SomeCondition when all the products are created, will we have a categories.ToArray(); Parallel.Foreach(products, p => { p.Category == categories.FirstOrDefault(c => c.Id == p.CategoryId); }); or categories.ToArray(); foreach(Product product in products) { product.Category = categories.FirstOrDefault(c => c.Id == product.CategoryId); } ?

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  • Custom RoleProvider: Can't insert record in UsersInRole Table

    - by mahr.g.mohyuddin
    Hi, I have implemented a LINQ to SQL based RoleProvider, when I assign role to a user following exception is thrown while AddUsersToRoles method is called. I have defined a composite primary key userid & roleId on this table, it still throwing this exception: Can't perform Create, Update or Delete operations on 'Table(UsersInRole)' because it has no primary key. My LinQ to SQL implementation of AddUsersToRoles method is as follows. It breaks at db.UsersInRoles.InsertOnSubmit(userInRole); using (RussarmsDataContext db = new RussarmsDataContext()) { List<UsersInRole> usersInRole = new List<UsersInRole>(); foreach (string username in usernames) { foreach (string rolename in rolenames) { UsersInRole userInRole = new UsersInRole(); object userId = ProvidersUtility.GetUserIdByUserName(username,applicationName); object roleId = ProvidersUtility.GetRoleIdByRoleName(rolename,applicationName); if (userId != null && roleId != null) { userInRole.UserId = (Guid)userId; userInRole.RoleId = (Guid)roleId; db.UsersInRoles.InsertOnSubmit(userInRole); } } } try { // db.UsersInRoles.InsertAllOnSubmit(usersInRole); db.SubmitChanges(); } catch (ChangeConflictException) { db.ChangeConflicts.ResolveAll(RefreshMode.OverwriteCurrentValues); db.SubmitChanges(); } } Any help will be appreciated. Thanks.

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  • Cross join (pivot) with n-n table containing values

    - by Styx31
    I have 3 tables : TABLE MyColumn ( ColumnId INT NOT NULL, Label VARCHAR(80) NOT NULL, PRIMARY KEY (ColumnId) ) TABLE MyPeriod ( PeriodId CHAR(6) NOT NULL, -- format yyyyMM Label VARCHAR(80) NOT NULL, PRIMARY KEY (PeriodId) ) TABLE MyValue ( ColumnId INT NOT NULL, PeriodId CHAR(6) NOT NULL, Amount DECIMAL(8, 4) NOT NULL, PRIMARY KEY (ColumnId, PeriodId), FOREIGN KEY (ColumnId) REFERENCES MyColumn(ColumnId), FOREIGN KEY (PeriodId) REFERENCES MyPeriod(PeriodId) ) MyValue's rows are only created when a real value is provided. I want my results in a tabular way, as : Column | Month 1 | Month 2 | Month 4 | Month 5 | Potatoes | 25.00 | 5.00 | 1.60 | NULL | Apples | 2.00 | 1.50 | NULL | NULL | I have successfully created a cross-join : SELECT MyColumn.Label AS [Column], MyPeriod.Label AS [Period], ISNULL(MyValue.Amount, 0) AS [Value] FROM MyColumn CROSS JOIN MyPeriod LEFT OUTER JOIN MyValue ON (MyValue.ColumnId = MyColumn.ColumnId AND MyValue.PeriodId = MyPeriod.PeriodId) Or, in linq : from p in MyPeriods from c in MyColumns join v in MyValues on new { c.ColumnId, p.PeriodId } equals new { v.ColumnId, v.PeriodId } into values from nv in values.DefaultIfEmpty() select new { Column = c.Label, Period = p.Label, Value = nv.Amount } And seen how to create a pivot in linq (here or here) : (assuming MyDatas is a view with the result of the previous query) : from c in MyDatas group c by c.Column into line select new { Column = line.Key, Month1 = line.Where(l => l.Period == "Month 1").Sum(l => l.Value), Month2 = line.Where(l => l.Period == "Month 2").Sum(l => l.Value), Month3 = line.Where(l => l.Period == "Month 3").Sum(l => l.Value), Month4 = line.Where(l => l.Period == "Month 4").Sum(l => l.Value) } But I want to find a way to create a resultset with, if possible, Month1, ... properties dynamic. Note : A solution which results in a n+1 query : from c in MyDatas group c by c.Column into line select new { Column = line.Key, Months = from l in line group l by l.Period into period select new { Period = period.Key, Amount = period.Sum(l => l.Value) } }

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  • LinqKit System.InvalidCastException When Invoking method-provided expression on member property.

    - by mdworkin
    Given a simple parent/child class structure. I want to use linqkit to apply a child lambda expression on the parent. I also want the Lambda expression to be provided by a utility method. public class Foo { public Bar Bar { get; set; } } public class Bar { public string Value { get; set; } public static Expression<Func<Bar, bool>> GetLambdaX() { return c => c.Value == "A"; } } ... Expression<Func<Foo, bool>> lx = c => Bar.GetLambdaX().Invoke(c.Bar); Console.WriteLine(lx.Expand()); The above code throws System.InvalidCastException: Unable to cast object of type 'System.Linq.Expressions.MethodCallExpression' to type 'System.Linq.Expressions.LambdaExpression'. at LinqKit.ExpressionExpander.VisitMethodCall(MethodCallExpression m) at LinqKit.ExpressionVisitor.Visit(Expression exp) at LinqKit.ExpressionVisitor.VisitLambda(LambdaExpression lambda) at LinqKit.ExpressionVisitor.Visit(Expression exp) at LinqKit.Extensions.Expand<TDelegate>(Expression`1 expr) .... Please help!

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  • Problem with .Contains

    - by Rene
    Hello there, I have a little problem which i can't solve. I want to use an SQL-In-Statement in Linq. I've read in this Forum and in other Forums that I have to use the .Contains (with reverse-thinking-notation :-)). As input i have a List of Guids. I first copied them into an array and then did something like that : datatoget = (from p in objectContext.MyDataSet where ArrayToSearch.Contains(p.Subtable.Id.ToString()) select p).ToList(); datatoget is the result in which all records matching the Subtable.Id (which is a Guid) should be stored. Subtable is a Detail-Table from MyData, and the Id is a Guid-Type. I've tried several things (Convert Guid to String, and then using .Contains, etc), but I always get an Exception which says : 'Linq to Entities' doesn't recognize the Method 'Boolean Contains(System.Guid) and is not able to Translate this method into a memory expression. (Something like that, because I'm using the German Version of VS2008) I am using L2E with .NET 3.5 and am programming in C# with VS 2008. I've read several Examples, but it doesn't work. Is it perhaps because of using Guid's instead of strings ? I've also tried to write my own compare-function, but I don't know how to integrate it so that .NET calls my function for comparing.

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  • Entity Framework 4 / POCO - Where to start?

    - by Basiclife
    Hi, I've been programming for a while and have used LINQ-To-SQL and LINQ-To-Entities before (although when using entities it has been on a Entity/Table 1-1 relationship - ie not much different than L2SQL) I've been doing a lot of reading about Inversion of Control, Unit of Work, POCO and repository patterns and would like to use this methodology in my new applications. Where I'm struggling is finding a clear, concise beginners guide for EF4 which doesn't assume knowledge of EF1. The specific questions I need answered are: Code first / model first? Pros/cons in regards to EF4 (ie what happens if I do code first, change the code at a later date and need to regenerate my DB model - Does the data get preserved and transformed or dropped?) Assuming I'm going code-first (I'd like to see how EF4 converts that to a DB schema) how do I actually get started? Quite often I've seen articles with entity diagrams stating "So this is my entity model, now I'm going to ..." - Unfortunately, I'm unclear if they're created the model in the designer, saved it to generate code then stopped any further auto-code generation -or- They've coded (POCO)? classes and the somehow imported them into the deisgner view? I suppose what I really need is an understanding of where the "magic" comes from and how to add it myself if I'm not just generating an EF model directly from a DB. I'm aware the question is a little vague but I don't know what I don't know - So any input / correction / clarification appreciated. Needless to say, I don't expect anyone to sit here and teach me EF - I'd just like some good tutorials/forums/blogs/etc. for complete entity newbies Many thanks in advance

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  • How to find unique values in jagged array

    - by David Liddle
    I would like to know how I can count the number of unique values in a jagged array. My domain object contains a string property that has space delimitered values. class MyObject { string MyProperty; //e.g = "v1 v2 v3" } Given a list of MyObject's how can I determine the number of unique values? The following linq code returns an array of jagged array values. A solution would be to store a temporary single array of items, looped through each jagged array and if values do not exist, to add them. Then a simple count would return the unique number of values. However, was wondering if there was a nicer solution. db.MyObjects.Where(t => !String.IsNullOrEmpty(t.MyProperty)) .Select(t => t.Categories.Split(new char[] { ' ' }, StringSplitOptions.RemoveEmptyEntries)) .ToArray() Below is a more readable example: array[0] = { "v1", "v2", "v3" } array[1] = { "v1" } array[2] = { "v4", "v2" } array[3] = { "v1", "v5" } From all values the unique items are v1, v2, v3, v4, v5. The total number of unique items is 5. Is there a solution, possibly using linq, that returns either only the unique values or returns the number of unique values?

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  • XDocument.Parse fails due to resolution error, how to disable resolution

    - by Frank Krueger
    I am trying to parse the contents of http://feeds.feedburner.com/riabiz using XDocument.Parse(string) (because it gets cached in a DB.) However, it keeps failing with the below stack trace when it tries to resolve some URIs in that XML. I don't care about validation or any of that XML nonsense, I just want the structure parsed. How can I use XDocument without this URI resolution? System.ArgumentException: The specified path is not of a legal form (empty). at System.IO.Path.InsecureGetFullPath (System.String path) [0x00000] in :0 at System.IO.Path.GetFullPath (System.String path) [0x00000] in :0 at System.Xml.XmlResolver.ResolveUri (System.Uri baseUri, System.String relativeUri) [0x00000] in :0 at System.Xml.XmlUrlResolver.ResolveUri (System.Uri baseUri, System.String relativeUri) [0x00000] in :0 at Mono.Xml2.XmlTextReader.ReadStartTag () [0x00000] in :0 at Mono.Xml2.XmlTextReader.ReadContent () [0x00000] in :0 at Mono.Xml2.XmlTextReader.Read () [0x00000] in :0 at System.Xml.XmlTextReader.Read () [0x00000] in :0 at Mono.Xml.XmlFilterReader.Read () [0x00000] in :0 at Mono.Xml.XmlFilterReader.Read () [0x00000] in :0 at System.Xml.XmlReader.ReadEndElement () [0x00000] in :0 at System.Xml.Linq.XElement.LoadCore (System.Xml.XmlReader r, LoadOptions options) [0x00000] in :0 at System.Xml.Linq.XNode.ReadFrom (System.Xml.XmlReader r, LoadOptions options) [0x00000] in :0 ...

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  • Understanding many to many relationships and Entity Framework

    - by Anders Svensson
    I'm trying to understand the Entity Framework, and I have a table "Users" and a table "Pages". These are related in a many-to-many relationship with a junction table "UserPages". First of all I'd like to know if I'm designing this relationship correctly using many-to-many: One user can visit multiple pages, and each page can be visited by multiple users..., so am I right in using many2many? Secondly, and more importantly, as I have understood m2m relationships, the User and Page tables should not repeat information. I.e. there should be only one record for each user and each page. But then in the entity framework, how am I able to add new visits to the same page for the same user? That is, I was thinking I could simply use the Count() method on the IEnumerable returned by a LINQ query to get the number of times a user has visited a certain page. But I see no way of doing that. In Linq to Sql I could access the junction table and add records there to reflect added visits to a certain page by a certain user, as many times as necessary. But in the EF I can't access the junction table. I can only go from User to a Pages collection and vice versa. I'm sure I'm misunderstanding relationships or something, but I just can't figure out how to model this. I could always have a Count column in the Page table, but as far as I have understood you're not supposed to design database tables like that, those values should be collected by queries... Please help me understand what I'm doing wrong...

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  • Problems finding classes in namespace and testing extend expected parent

    - by Matt
    So I am in the process of building a site in ASP.Net MVC, and in the process I am adding certain things to my Site.Master I want to make sure that all of my model classes extend a certain base class that contains all of the pieces the Site.Master needs to be operable. I want to test to make sure this assumption isn't broken (I believe this will save me time when I forget about it and can't figure out why a new combination isn't working.) I wrote a test that I thought would help with this, but I am running into two problems. First it isn't finding the one example model class I have so far in the LINQ call all of a sudden, I am admittedly still a bit new to LINQ. Second, I had it finding the class earlier, but I couldn't get it to verify that the class inherits from the base class. Here is the example test. [Test] public void AllModelClassesExtendAbstractViewModel() { var abstractViewModelType = typeof (AbstractViewModel); Assembly baseAssembly = Assembly.GetAssembly(abstractViewModelType); var modelTypes = baseAssembly.GetTypes() .Where(assemblyType => (assemblyType.Namespace.EndsWith("Models") && assemblyType.Name != "AbstractViewModel")) .Select(assemblyType => assemblyType); foreach (var modelType in modelTypes) { Assert.That(modelType.IsSubclassOf(abstractViewModelType), Is.True , modelType.Name + " does not extend AbstractViewModel"); } }

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  • How can you pre-define a variable that will contain an anonymous type?

    - by HitLikeAHammer
    In the simplified example below I want to define result before it is assinged. The linq queries below return lists of anonymous types. result will come out of the linq queries as an IEnumerable<'a but I can't define it that way at the top of the method. Is what I am trying to do possible (in .NET 4)? bool large = true; var result = new IEnumerable(); //This is wrong List<int> numbers = new int[]{1,2,3,4,5,6,7,8,9,10}.ToList<int>(); if (large) { result = from n in numbers where n > 5 select new { value = n }; } else { result = from n in numbers where n < 5 select new { value = n }; } foreach (var num in result) { Console.WriteLine(num.value); } EDIT: To be clear I know that I do not need anonymous types in the example above. It is just to illustrate my question with a small, simple example.

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  • Entity Framework: Auto-updating foreign key when setting a new object reference

    - by Adrian Grigore
    Hi, I am porting an existing application from Linq to SQL to Entity Framework 4 (default code generation). One difference I noticed between the two is that a foreign key property are not updated when resetting the object reference. Now I need to decide how to deal with this. For example supposing you have two entity types, Company and Employee. One Company has many Employees. In Linq To SQL, setting the company also sets the company id: var company=new Company(ID=1); var employee=new Employee(); Debug.Assert(employee.CompanyID==0); employee.Company=company; Debug.Assert(employee.CompanyID==1); //Works fine! In Entity Framework (and without using any code template customization) this does not work: var company=new Company(ID=1); var employee=new Employee(); Debug.Assert(employee.CompanyID==0); employee.Company=company; Debug.Assert(employee.CompanyID==1); //Throws, since CompanyID was not updated! How can I make EF behave the same way as LinqToSQL? I had a look at the default code generation T4 template, but I could not figure out how to make the necessary changes.

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  • How can I have 2 ADO access methods use the same Transaction?

    - by KevinDeus
    I'm writing a test to see if my LINQ to Entity statement works.. I'll be using this for others if I can get this concept going.. my intention here is to INSERT a record with ADO, then verify it can be queried with LINQ, and then ROLLBACK the whole thing at the end. I'm using ADO to insert because I don't want to use the object or the entity model that I am testing. I figure that a plain ADO INSERT should do fine. problem is.. they both use different types of connections. is it possible to have these 2 different data access methods use the same TRANSACTION so I can roll it back?? _conn = new SqlConnection(_connectionString); _conn.Open(); _trans = _conn.BeginTransaction(); var x = new SqlCommand("INSERT INTO Table1(ID, LastName, FirstName, DateOfBirth) values('127', 'test2', 'user', '2-12-1939');", _conn); x.ExecuteNonQuery(); //So far, so good. Adding a record to the table. //at this point, we need to do **_trans.Commit()** here because our Entity code can't use the same connection. Then I have to manually delete in the TestHarness.TearDown.. I'd like to eliminate this step //(this code is in another object, I'll include it for brevity. Imagine that I passed the connection in) //check to see if it is there using (var ctx = new XEntities(_conn)) //can't do this.. _conn is not an EntityConnection! { var retVal = (from m in ctx.Table1 where m.first_name == "test2" where m.last_name == "user" where m.Date_of_Birth == "2-12-1939" where m.ID == 127 select m).FirstOrDefault(); return (retVal != null); } //Do test.. Assert.BlahBlah(); _trans.Rollback();

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