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  • Python web frameworks comparisons

    - by stupidLearner
    I recently asked a question on SO about Python web frameworks: http://stackoverflow.com/questions/4909306/python-web-frameworks-vs-java-web-frameworks-how-is-web-development-in-python-do I want to learn one just for fun but it also has to be able to help me deliver a proper working application. I am looking for a framework with lots of features, powerful, mature, with large community, good documentation, books etc. I need something that will help me be more productive in developing my app and not waste time figuring out how to do a certain thing in the framework or how to write workaround around the limitations of the framework. I was thinking one of the following: django, zope, turbogears, pylons. Off course the war is raging out there and there are other alternatives but seems Django is at the top... or is it just hype? I am interested in pros and cons of each. What was the best feature you think the framework has? What is the thing it lacks? What could have been done differently. Help me chose one to learn for starters.

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  • Algorithm to optimize grouping

    - by Jeroen
    I would like to know if there's a known algorithm or best practice way to do the following: I have a collection with a subcollection, for example: R1 R2 R3 -- -- -- M M M N N L L A What i need is an algorithm to get the following result: R1, R2: M N L R2: A R3: M This is -not- what i want, it has more repeating values for R than the above: R1, R2, R3: M R1, R2: N L R2: A I need to group in way that i get the most optimized groups of R. The least amount of groups of R the better so i get the largest sub collections. Another example (with the most obvious result): R1 R2 R3 -- -- -- M M A V V B L L C Should result in: R1, R2: M V L R3: A B C I need to do this in LINQ/C#. Any solutions? Tips? Links?

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  • Appropriate level of granularity for component-based architecture

    - by Jon Purdy
    I'm working on a game with a component-based architecture. An Entity owns a set of Component instances, each of which has a set of Slot instances with which to store, send, and receive values. Factory functions such as Player produce entities with the required components and slot connections. I'm trying to determine the best level of granularity for components. For example, right now Position, Velocity, and Acceleration are all separate components, connected in series. Velocity and Acceleration could easily be rewritten into a uniform Delta component, or Position, Velocity, and Acceleration could be combined alongside such components as Friction and Gravity into a monolithic Physics component. Should a component have the smallest responsibility possible (at the cost of lots of interconnectivity) or should related components be combined into monolithic ones (at the cost of flexibility)? I'm leaning toward the former, but I could use a second opinion.

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  • Local Entities with NHibernate

    - by Ricardo Peres
    You may know that Entity Framework Code First has a nice property called Local which lets you iterate through all the entities loaded by the current context (first level cache). This comes handy at times, so I decided to check if it would be difficult to have it on NHibernate. It turned out it is not, so here it is! Another nice addition to an NHibernate toolbox! public static class SessionExtensions { public static IEnumerable<T> Local<T>(this ISession session) { ISessionImplementor impl = session.GetSessionImplementation(); IPersistenceContext pc = impl.PersistenceContext; foreach (Object key in pc.EntityEntries.Keys) { if (key is T) { yield return ((T) key); } } } } //simple usage IEnumerable<Post> localPosts = session.Local<Post>(); SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.brushes.CSharp.aliases = ['c#', 'c-sharp', 'csharp']; SyntaxHighlighter.all();

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  • The underlying provider failed on Open

    - by aghausman12
    The underlying provider failed on Open is an entity framework error and with a simple fix it is little difficult to sort out what is going wrong. 1) if you are using IIS 7 with Integrated Security in connection string. Make sure your IIS user have appropriate permissions to access database. 2) If you are using Visual Studio built in Web Server and facing this issue. Simple fix is to either re-start Visual Studio or Kill the process of Web Server which is (WebDev.WebServer*.exe). I was in the second...(read more)

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  • delete elements in xml?

    - by fayer
    i've got some elements in a xml document i want to delete. so i want to create another xml document without those elements. here is an example of how it looks like at the moment: <entity id="1000070"> <name>apple</name> <type>category</type> <entities> <entity id="7002870"> <name>mac</name> <type>category</type> <entities> <entity id="7002907"> <name>leopard</name> <type>sub-category</type> <entities> <entity id="7024080"> <name>safari</name> <type>subject</type> </entity> <entity id="7024701"> <name>finder</name> <type>subject</type> </entity> </entities> </entity> </entities> </entity> <entity id="7024080"> <name>iphone</name> <type>category</type> <entities> <entity id="7024080"> <name>3g</name> <type>sub-category</type> </entity> <entity id="7024701"> <name>3gs</name> <type>sub-category</type> </entity> </entities> </entity> <entity id="7024080"> <name>ipad</name> <type>category</type> </entity> </entities> </entity> i want to create another xml document without the sub-category and subject elements. so the new one will look like this: <entity id="1000070"> <name>apple</name> <type>category</type> <entities> <entity id="7002870"> <name>mac</name> <type>category</type> </entity> <entity id="7024080"> <name>iphone</name> <type>category</type> </entity> <entity id="7024080"> <name>ipad</name> <type>category</type> </entity> </entities> </entity> should i use simplexml/php or xslt to do this? are there other ways? would be great with some code examples...thanks!

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  • Anyone got Twitter xAuth working with the Compact Framework yet?

    - by peSHIr
    This question is related to a number of other questions on oAuth on the Compact Framework (one, two) but seems slightly more specific to me, as it specifically involves getting Twitters xAuth API call (meant for non web applications to be able to do oAuth) working on the Compact Framework. Are SSL HTTP connections and the encryption methods needed for xAuth needed part of Compact Framework 3.5? Did anyone get the Twitter xAuth working on Windows Mobile already? If so, what libraries did you use for this? Any tips are welcome.

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  • Expand in linq not loading inner data collections from service.

    - by Kit
    I am seeing odd behavior with service queries! I am using MVVM pattern for a silverlight 3 app on 3.5 framework and Dataservices 1.5. The following code eager loads correctly the parent object and the child heirarchy perfectly IF and ONLY IF I am preloading the data. But I would like to fetch a different set of the parent object (and its child heirarchy) on different button clicks. What I am seeing is that on button click, only the parent object is retrieved, and the child heirarchy contains nothing. Any suggestions? Any ideas how to tackle this? Thanks all. The method: DataServiceQuery serviceQuery = (DataServiceQuery)(from m1 in dbEntities.gis_Region.Expand("gis_RegionValue/gis_Measure") where m1.RegionGuid == new Guid(regionGuid) select m1); serviceQuery.BeginExecute(GetRegionDetailAsyncResult, serviceQuery); The wired Async Result: DataServiceQuery query = (DataServiceQuery)result.AsyncState; gis_Region region = query.EndExecute(result).First();

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  • PHP / Zend Framework: Which object would handle a complex table join?

    - by Thomas
    I think one of the more difficult concepts to understand in the Zend Framework is how the Table Data Gateway pattern is supposed to handle multi-table joins. Most of the suggestions I've seen claim that you simply handle the joins using a $db-select()... Zend DB Select with multiple table joins Joining Tables With Zend Framework PHP Joining tables wthin a model in Zend Php Zend Framework Db Select Join table help Zend DB Select with multiple table joins My question is: Which object is best suited to handle this kind of multi-table select statement? I feel like putting it in the model would break the 1-1 Table Data Gateway pattern between the class and the db table. Yet putting it in the controller seems wrong because why would a controller handle a SQL statement? Anyway, I feel like ZF makes handling datasets from multiple tables more difficult than it needs to be. Any help you can provide is great... Thanks!

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  • What features do you expect from a Java (Rich) Client Framework?

    - by Peter Walser
    I'm intending to design (and provide a reference implementation for) a new Swing Rich Client Framework. My job and personal experience covers many project-specific Swing client frameworks as well as the Eclipse RCP, and every one of them had some original and clever concepts, but also drawbacks and rigid realizations. My plan is to incorporate the best of those concepts and features into a new framework whose core is very open and extendable. For my must-have-features list, I'm counting on your input and hope you can share some concept pearls & diamonds you've encountered in other frameworks, or features you always wanted to have or have in a better way. The framework is intended for very simple to very complex and sophisticated projects for clients that need full i18n for richt clients that execute some or all of the non-presentation logic on the server to be very lightweight to be easy to learn and use Thanks in advance for sharing your insights :)

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  • How can I catch connection requests in my framework?

    - by Falx
    I'm building a framework (OSGi-like) where other parties can program a bundle for. But I want my framework to manage the QoS of the connection-requests that the other parties will do. The easy solution would be to ask them to use (or enforce them to use - although I don't know how) a specific ConnectionRequest bundle of the framework. The problem with this approach is that they wouldn't be able to use any of their own preferred libraries that is counting on the standard Java libraries to make a connection(request). So I wondered if there is a way in Java to catch all the requested connections, so I can add some code about my QoS handling, before its is sent of to the underlaying layer?

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  • How to check the compatibility between my program and the .net framework versions?

    - by Jack
    Hi all I am writing a program which is targeted to run on .net framework 2.0. I have chosen 2.0 in my VS project. It runs fine on my machine (mine has 2.0 SP2), so there is no compile error. but when I tried to run it on another machine (only with 2.0, no sp), it cannot run. I am aware that I used some method which is supported by 2.0 but only with 2.0 SP2. .net framework 2.0 SP2 seems not being listed in VS IDE, that's why VS cannot give me any warning when I compiled it on my machine. How can I easily check the compatibility of my codes with .net framework 2.0 SP2? or I just have to look at msdn to check every method I have used??? thanks

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  • Is there any real advantage to use zend ce server over just referencing (include) the zend framework library?

    - by Marcos Roriz
    Hi, I'm new to PHP frameworks, and currently I'm trying Zend Framework (ZF). I'm old fashioned when it comes to installing software, I like to install apache/mysql/php all separetely since I find easier and it gives me more control of it. It seems that the "encouraged" way to develop with Zend Framework is using the Zend (CE) Server. I personally don't like this idea of a app install everything else (PHP/Apache and so on). From what I've seen if I include Zend Framework Library in php.ini path I'm ready to go. So is there any real advantage to use the Full Zend (CE) Server??

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  • VB.NET IF() Coalesce and “Expression Expected” Error

    - by Jeff Widmer
    I am trying to use the equivalent of the C# “??” operator in some VB.NET code that I am working in. This StackOverflow article for “Is there a VB.NET equivalent for C#'s ?? operator?” explains the VB.NET IF() statement syntax which is exactly what I am looking for... and I thought I was going to be done pretty quickly and could move on. But after implementing the IF() statement in my code I started to receive this error: Compiler Error Message: BC30201: Expression expected. And no matter how I tried using the “IF()” statement, whenever I tried to visit the aspx page that I was working on I received the same error. This other StackOverflow article Using VB.NET If vs. IIf in binding/rendering expression indicated that the VB.NET IF() operator was not available until VS2008 or .NET Framework 3.5.  So I checked the Web Application project properties but it was targeting the .NET Framework 3.5: So I was still not understanding what was going on, but then I noticed the version information in the detailed compiler output of the error page: This happened to be a C# project, but with an ASPX page with inline VB.NET code (yes, it is strange to have that but that is the project I am working on).  So even though the project file was targeting the .NET Framework 3.5, the ASPX page was being compiled using the .NET Framework 2.0.  But why?  Where does this get set?  How does ASP.NET know which version of the compiler to use for the inline code? For this I turned to the web.config.  Here is the system.codedom/compilers section that was in the web.config for this project: <system.codedom>     <compilers>         <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">             <providerOption name="CompilerVersion" value="v3.5" />             <providerOption name="WarnAsError" value="false" />         </compiler>     </compilers> </system.codedom> Keep in mind that this is a C# web application project file but my aspx file has inline VB.NET code.  The web.config does not have any information for how to compile for VB.NET so it defaults to .NET 2.0 (instead of 3.5 which is what I need). So the web.config needed to include the VB.NET compiler option.  Here it is with both the C# and VB.NET options (I copied the VB.NET config from a new VB.NET Web Application project file).     <system.codedom>         <compilers>             <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">                 <providerOption name="CompilerVersion" value="v3.5" />                 <providerOption name="WarnAsError" value="false" />             </compiler>       <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" warningLevel="4" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">         <providerOption name="CompilerVersion" value="v3.5"/>         <providerOption name="OptionInfer" value="true"/>         <providerOption name="WarnAsError" value="false"/>       </compiler>     </compilers>     </system.codedom>   So the inline VB.NET code on my aspx page was being compiled using the .NET Framework 2.0 when it really needed to be compiled with the .NET Framework 3.5 compiler in order to take advantage of the VB.NET IF() coalesce statement.  Without the VB.NET web.config compiler option, the default is to compile using the .NET Framework 2.0 and the VB.NET IF() coalesce statement does not exist (at least in the form that I want it in).  FYI, there is an older IF statement in VB.NET 2.0 compiler which is why it is giving me the unusual “Expression Expected” error message – see this article for when VB.NET got the new updated version. EDIT (2011-06-20): I had made a wrong assumption in the first version of this blog post.  After a little more research and investigation I was able to figure out that the issue was in the web.config and not with the IIS App Pool.  Thanks to the comment from James which forced me to look into this again.

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  • EntityDataSource Control Basics

    The Entity Framework can be easily used to create websites based on ASP.NET. The EntityDataSource control, which is one of a set of Web Server Datasource controls, can be used to to bind an Entity Data Model (EDM) to data-bound controls on the page. Thse controls can be editable grids, forms, drop-down list controls and master-detail pages which can then be used to create, read, update, and delete data. Joydip tells you what you need to get started.

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  • Linq The specified type 'string' is not a valid provider type.

    - by Joe Pitz
    Using Linq to call a stored procedure that passes a single string, The stored procedure returns a data set row that contains a string and an int. Code: PESQLDataContext pe = new PESQLDataContext(strConnStr); pe.ObjectTrackingEnabled = false; gvUnitsPassed.DataSource = pe.PassedInspection(Line); gvUnitsPassed.DataBind(); pe.dispose(); When the code runs an exception gets called below: The exception is thrown at the IExecuteResult result = statement: Enclosed is my result class in the designer.cs file. [Function(Name = "dbo.PassedInspection")] public ISingleResult<PassedInspectionResult> PassedInspection([Parameter(Name = "Model", DbType = "VarChar(4)")] string model) { IExecuteResult result = this.ExecuteMethodCall(this, ((MethodInfo)(MethodInfo.GetCurrentMethod())), model); return ((ISingleResult<PassedInspectionResult>)(result.ReturnValue)); } public partial class PassedInspectionResult { private string _Date; private int _Passed; public PassedInspectionResult() { } [Column(Storage = "_Date", DbType = "string NULL")] public string Date { get { return this._Date; } set { if ((this._Date != value)) { this._Date = value; } } } [Column(Storage = "_Passed", DbType = "Int NULL")] public int Passed { get { return this._Passed; } set { if ((this._Passed != value)) { this._Passed = value; } } } } } I have other stored procedures with similar arguments that run just fine. Thanks

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  • Validate MVC 2 form using Data annotations and Linq-to-SQL, before the model binder kicks in (with D

    - by Stefanvds
    I'm using linq to SQL and MVC2 with data annotations and I'm having some problems on validation of some types. For example: [DisplayName("Geplande sessies")] [PositiefGeheelGetal(ErrorMessage = "Ongeldige ingave. Positief geheel getal verwacht")] public string Proj_GeplandeSessies { get; set; } This is an integer, and I'm validating to get a positive number from the form. public class PositiefGeheelGetalAttribute : RegularExpressionAttribute { public PositiefGeheelGetalAttribute() : base(@"\d{1,7}") { } } Now the problem is that when I write text in the input, I don't get to see THIS error, but I get the errormessage from the modelbinder saying "The value 'Tomorrow' is not valid for Geplande sessies." The code in the controller: [HttpPost] public ActionResult Create(Projecten p) { if (ModelState.IsValid) { _db.Projectens.InsertOnSubmit(p); _db.SubmitChanges(); return RedirectToAction("Index"); } else { SelectList s = new SelectList(_db.Verbonds, "Verb_ID", "Verb_Naam"); ViewData["Verbonden"] = s; } return View(); } What I want is being able to run the Data Annotations before the Model binder, but that sounds pretty much impossible. What I really want is that my self-written error messages show up on the screen. I have the same problem with a DateTime, which i want the users to write in the specific form 'dd/MM/yyyy' and i have a regex for that. but again, by the time the data-annotations do their job, all i get is a DateTime Object, and not the original string. So if the input is not a date, the regex does not even run, cos the data annotations just get a null, cos the model binder couldn't make it to a DateTime. Does anyone have an idea how to make this work?

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  • How can I access the group of a linq group-by query from a nested repeater control?

    - by Duke
    I'm using a linq group by query (with two grouping parameters) and would like to use the resulting data in a nested repeater. var dateGroups = from row in data.AsEnumerable() group row by new { StartDate = row["StartDate"], EndDate = row["EndDate"] }; "data" is a DataTable from an SqlDataAdapter-filled DataSet. "dateGroups" is used in the parent repeater, and I can access the group keys using Eval("key.StartDate") and Eval("key.EndDate"). Since dateGroups actually contains all the data rows grouped neatly by Start/End date, I'd like to access those rows to display the data in a child repeater. To what would I set the child repeater's DataSource? I have tried every expression in markup I could think of; I think the problem is that I'm trying to access an anonymous member (and I don't know how.) In case it doesn't turn out to be obvious, what would be the expression to access the elements in each iteration of the child repeater? Is there an expression that would let me set the DataSource in the markup, or will it have to be in the codebehind on some event in the parent repeater?

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  • LINQ-to-SQL: How can I prevent 'objects you are adding to the designer use a different data connecti

    - by Timothy Khouri
    I am using Visual Studio 2010, and I have a LINQ-to-SQL DBML file that my colleagues and I are using for this project. We have a connection string in the web.config file that the DBML is using. However, when I drag a new table from my "Server Explorer" onto the DBML file... I get presented with a dialog that demands that do one of these two options: Allow visual studio to change the connection string to match the one in my solution explorer. Cancel the operation (meaning, I don't get my table). I don't really care too much about the debate as why the PMs/devs who made this tool didn't allow a third option - "Create the object anyway - don't worry, I'm a developer!" What I am thinking would be a good solution is if I can create a connection in the Server Explorer - WITHOUT A WIZARD. If I can just paste a connection string, that would be awesome! Because then the DBML designer won't freak out on me :O) If anyone knows the answer to this question, or how to do the above, please lemme know!

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  • Can someone help me refactor this C# linq business logic for efficiency?

    - by Russell
    I feel like this is not a very efficient way of using linq. I was hoping somebody on here would have a suggestion for a refactor. I realize this code is not very pretty, as I was in a complete rush. public class Workflow { public void AssignForms() { using (var cntx = new ProjectBusiness.Providers.ProjectDataContext()) { var emplist = (from e in cntx.vw_EmployeeTaskLists where e.OwnerEmployeeID == null select e).ToList(); foreach (var emp in emplist) { // if employee has a form assigned: break; if (emp.GRADE > 15 || (emp.Pay_Plan.ToLower().Contains("al") || emp.Pay_Plan.ToLower().Contains("ex"))) { //Assign278(); } else if ((emp.Series.Contains("0905") || emp.Series.Contains("0511") || emp.Series.Contains("0110") || emp.Series.Contains("1801")) || (emp.GRADE >= 12 && emp.GRADE <= 15)) { var emptask = new ProjectBusiness.Providers.EmployeeTask(); emptask.TimespanID = cntx.Timespans.SingleOrDefault(t => t.BeginDate.Year == DateTime.Today.Year & t.EndDate.Year == DateTime.Today.Year).TimespanID; var FormID = (from f in cntx.Forms where f.FormName.Contains("450") select f.FormID).FirstOrDefault(); var TaskStatusID = (from s in cntx.TaskStatus where s.StatusDescription.ToLower() == "not started" select s.TaskStatusID).FirstOrDefault(); Assign450((int)emp.EmployeeID, FormID, TaskStatusID, emptask); cntx.EmployeeTasks.InsertOnSubmit(emptask); } else { //Assign185(); } } cntx.SubmitChanges(); } } private void Assign450(int EmployeeID, int FormID, int TaskStatusID, ProjectBusiness.Providers.EmployeeTask emptask) { emptask.FormID = FormID; emptask.OwnerEmployeeID = EmployeeID; emptask.AssignedToEmployeeID = EmployeeID; emptask.TaskStatusID = TaskStatusID; emptask.DueDate = DateTime.Today; } }

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  • Getting minimum - Min() - for DateTime column in a DataTable using LINQ to DataSets?

    - by Jay Stevens
    I need to get the minimum DateTime value of a column in a DataTable. The DataTable is generated dynamically from a CSV file, therefore I don't know the name of that column until runtime. Here is code I've got that doesn't work... private DateTime GetStartDateFromCSV(string inputFile, string date_attr) { EnumerableRowCollection<DataRow> table = CsvStreamReader.GetDataTableFromCSV(inputFile, "input", true).AsEnumerable(); DateTime dt = table.Select(record => record.Field<DateTime>(date_attr)).Min(); return dt; } The variable table is broken out just for clarity. I basically need to find the minimum value as a DateTime for one of the columns (to be chosen at runtime and represented by date_attr). I have tried several solutions from SO (most deal with known columns and/or non-DateTime fields). What I've got throws an error at runtime telling me that it can't do the DateTime conversion (that seems to be a problem with Linq?) I've confirmed that the data for the column name that is in the string date_attr is a date value.

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  • How can I get this dynamic WHERE statement in my LINQ-to-XML to work?

    - by Edward Tanguay
    In this question Jon Skeet offered a very interesting solution to making a LINQ-to-XML statement dynamic, but my knowledge of lambdas and delegates is not yet advanced enough to implement it: I've got it this far, but of course I get the error "smartForm does not exist in the current context": private void LoadWithId(int id) { XDocument xmlDoc = null; try { xmlDoc = XDocument.Load(FullXmlDataStorePathAndFileName); } catch (Exception ex) { throw new Exception(String.Format("Cannot load XML file: {0}", ex.Message)); } Func<XElement, bool> whereClause = (int)smartForm.Element("id") == id"; var smartForms = xmlDoc.Descendants("smartForm") .Where(whereClause) .Select(smartForm => new SmartForm { Id = (int)smartForm.Element("id"), WhenCreated = (DateTime)smartForm.Element("whenCreated"), ItemOwner = smartForm.Element("itemOwner").Value, PublishStatus = smartForm.Element("publishStatus").Value, CorrectionOfId = (int)smartForm.Element("correctionOfId"), IdCode = smartForm.Element("idCode").Value, Title = smartForm.Element("title").Value, Description = smartForm.Element("description").Value, LabelWidth = (int)smartForm.Element("labelWidth") }); foreach (SmartForm smartForm in smartForms) { _collection.Add(smartForm); } } Ideally I want to be able to just say: var smartForms = GetSmartForms(smartForm=> (int) smartForm.Element("DisplayOrder").Value > 50); I've got it this far, but I'm just not grokking the lambda magic, how do I do this? public List<SmartForm> GetSmartForms(XDocument xmlDoc, XElement whereClause) { var smartForms = xmlDoc.Descendants("smartForm") .Where(whereClause) .Select(smartForm => new SmartForm { Id = (int)smartForm.Element("id"), WhenCreated = (DateTime)smartForm.Element("whenCreated"), ItemOwner = smartForm.Element("itemOwner").Value, PublishStatus = smartForm.Element("publishStatus").Value, CorrectionOfId = (int)smartForm.Element("correctionOfId"), IdCode = smartForm.Element("idCode").Value, Title = smartForm.Element("title").Value, Description = smartForm.Element("description").Value, LabelWidth = (int)smartForm.Element("labelWidth") }); }

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  • How does Select statement works in a Dynamic Linq Query?

    - by Richard77
    Hello, 1) I've a Product table with 4 columns: ProductID, Name, Category, and Price. Here's the regular linq to query this table. public ActionResult Index() { private ProductDataContext db = new ProductDataContext(); var products = from p in db.Products where p.Category == "Soccer" select new ProductInfo { Name = p.Name, Price = p.Price} return View(products); } Where ProductInfo is just a class that contains 2 properties (Name and Price). The Index page Inherits ViewPage - IEnumerable - ProductInfo. Everything works fine. 2) To dynamicaly execute the above query, I do this: Public ActionResult Index() { var products = db.Products .Where("Category = \"Soccer\"") .Select(/* WHAT SOULD I WRITE HERE TO SELECT NAME & PRICE?*/) return View(products); } I'm using both 'System.Lind.Dynamic' namespace and the DynamicLibrary.cs (downloaded from ScottGu blog). Here are my questions: What expression do I use to select only Name and Price? (Most importantly) How do I retrieve the data in my view? (i.e. What type the ViewPage inherits? ProductInfo?)

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  • Linq-to-SQL: How to shape the data with group by?

    - by Cheeso
    I have an example database, it contains tables for Movies, People and Credits. The Movie table contains a Title and an Id. The People table contains a Name and an Id. The Credits table relates Movies to the People that worked on those Movies, in a particular role. The table looks like this: CREATE TABLE [dbo].[Credits] ( [Id] [int] IDENTITY (1, 1) NOT NULL PRIMARY KEY, [PersonId] [int] NOT NULL FOREIGN KEY REFERENCES People(Id), [MovieId] [int] NOT NULL FOREIGN KEY REFERENCES Movies(Id), [Role] [char] (1) NULL In this simple example, the [Role] column is a single character, by my convention either 'A' to indicate the person was an actor on that particular movie, or 'D' for director. I'd like to perform a query on a particular person that returns the person's name, plus a list of all the movies the person has worked on, and the roles in those movies. If I were to serialize it to json, it might look like this: { "name" : "Clint Eastwood", "movies" : [ { "title": "Unforgiven", "roles": ["actor", "director"] }, { "title": "Sands of Iwo Jima", "roles": ["director"] }, { "title": "Dirty Harry", "roles": ["actor"] }, ... ] } How can I write a LINQ-to-SQL query that shapes the output like that? I'm having trouble doing it efficiently. if I use this query: int personId = 10007; var persons = from p in db.People where p.Id == personId select new { name = p.Name, movies = (from m in db.Movies join c in db.Credits on m.Id equals c.MovieId where (c.PersonId == personId) select new { title = m.Title, role = (c.Role=="D"?"director":"actor") }) }; I get something like this: { "name" : "Clint Eastwood", "movies" : [ { "title": "Unforgiven", "role": "actor" }, { "title": "Unforgiven", "role": "director" }, { "title": "Sands of Iwo Jima", "role": "director" }, { "title": "Dirty Harry", "role": "actor" }, ... ] } ...but as you can see there's a duplicate of each movie for which Eastwood played multiple roles. How can I shape the output the way I want?

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  • Automatic .NET code, nhibernate session, and LINQ datacontext clean-up?

    - by AverageJoe719
    Hi all, in my goal to adopt better coding practices I have a few questions in general about automatic handling of code. I have heard different answers both from online and talking with other developers/programmers at my work. I am not sure if I should have split them into 3 questions, but they all seem sort of related: 1) How does .NET handle instances of classes and other code things that take up memory? I recently found out about using the factory pattern for certain things like service classes so that they are only instantiated once in the entire application, but then I was told that '.NET handles a lot of that stuff automatically when mentioning it.' 2) How does Nhibernate's session handle automatic clean-up of un-used things? I've seen some say that it is great at handling things automatically and you should just use a session factory and that's it, no need to close it. But I have also read and seem many examples where people close the hibernate session. 3) How does LINQ's datacontext handle this? Most of the time I never .disposed my datacontext's and the app didn't see to take a performance hit (though I am not running anything super intensively), but it seems like most people recommend disposing of your datacontext after you are done with it. However, I have seen many many code examples where the dispose method is never called. Also in general I found it kind of annoying that you couldn't access even one-deep child related objects after disposing of the datacontext unless you explicity also grabbed them in the query. Thanks all. I am loving this site so far, I kind of get lost and spend hours just reading things on here. =)

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