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  • Using an existing IQueryable to create a new dynamic IQueryable

    - by dnoxs
    I have a query as follows: var query = from x in context.Employees where (x.Salary > 0 && x.DeptId == 5) || x.DeptId == 2 order by x.Surname select x; The above is the original query and returns let's say 1000 employee entities. I would now like to use the first query to deconstruct it and recreate a new query that would look like this: var query = from x in context.Employees where ((x.Salary > 0 && x.DeptId == 5) || x.DeptId == 2) && (x,i) i % 10 == 0 order by x.Surname select x.Surname; This query would return 100 surnames. The syntax is probably incorrect, but what I need to do is attach an additional where clause and modify the select to a single field. I've been looking into the ExpressionVisitor but I'm not entirely sure how to create a new query based on an existing query. Any guidance would be appreciated. Thanks you.

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  • Settings variable values in a Moq Callback() call

    - by Adam Driscoll
    I think I may be a bit confused on the syntax of the Moq Callback methods. When I try to do something like this: IFilter filter = new Filter(); List<IFoo> objects = new List<IFoo> { new Foo(), new Foo() }; IQueryable myFilteredFoos = null; mockObject.Setup(m => m.GetByFilter(It.IsAny<IFilter>())).Callback( (IFilter filter) => myFilteredFoos = filter.FilterCollection(objects)).Returns(myFilteredFoos.Cast<IFooBar>()); This throws a exception because myFilteredFoos is null during the Cast<IFooBar>() call. Is this not working as I expect? I would think FilterCollection would be called and then myFilteredFoos would be non-null and allow for the cast. FilterCollection is not capable of returning a null which draws me to the conclusion it is not being called. Also, when I declare myFilteredFoos like this: Queryable myFilteredFoos; The Return call complains that myFilteredFoos may be used before it is initialized.

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  • how to use Foreign key in L2E or EF?

    - by 5YrsLaterDBA
    I have a User table which has a PrivilegeId foreign key points to a Privilege table and is the primary key there. In Entity Framework, the VS will not generate a PrivilegeId variable under Users for you. It will generate a Privilege property and PrivilegeReference property for you instead. When I load a User, the Privilege property is null by default. That means EF does not load refered entity for you automatically. I think I may did something wrong? I cannot load Privilege separatedly because I have no info about the Privilege at that time. I guess EF should load the refered entities for me but I missed something. anybody can help me?

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  • How can I combine several Expressions into a fast method?

    - by chillitom
    Suppose I have the following expressions: Expression<Action<T, StringBuilder>> expr1 = (t, sb) => sb.Append(t.Name); Expression<Action<T, StringBuilder>> expr2 = (t, sb) => sb.Append(", "); Expression<Action<T, StringBuilder>> expr3 = (t, sb) => sb.Append(t.Description); I'd like to be able to compile these into a method/delegate equivalent to the following: void Method(T t, StringBuilder sb) { sb.Append(t.Name); sb.Append(", "); sb.Append(t.Description); } What is the best way to approach this? I'd like it to perform well, ideally with performance equivalent to the above method. UPDATE So, whilst it appears that there is no way to do this directly in C#3 is there a way to convert an expression to IL so that I can use it with System.Reflection.Emit?

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  • Expression Tree Binary Expression for an 'In' operation

    - by Adam Driscoll
    I'm trying to build an expression tree (still) but getting further! I need to create a BinaryExpression to perform an 'In' comparison between a Member and a collection of items. Hence, the expression should return true if the member is contained within the items. This obviously does not exist: Expression.MakeBinary(ExpressionType.In, memberExpression, constantExpression); constantExpression is a ConstantExpression of type IEnumerable while memberExpression is a MemberExpression of type T. How would I create such an expression?

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  • Removing table prefixes on ASP.NET MVC DataModel entities

    - by Tim Shults
    My database tables have prefixes on them and when the DataModel generates the EntityObjects they have the prefixes at the beginning of the class name. Is there anyway that I can have those prefixes ignored when the DataModel is updating/creating the classes? I've found the below question, but with no solution. http://stackoverflow.com/questions/1800065/removing-table-prefix-in-linq2sql-setup/2525827#2525827 Thanks in advance, Tim Shults

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  • XML to Type - Quick way?

    - by MRFerocius
    Team; How are you doing? Im breaking my head trying to do this that seems simple but I can't figure it out... Suppose I have this XML as a string: <calles> <calle> <nombre>CALLAO AV.</nombre> <altura>1500</altura> <longitud>-58.3918617027</longitud> <latitud>-34.5916734896</latitud> <barrio>Recoleta</barrio> </calle> </calles> And and have this Type I created to map that XML: public class Ubicacion { public string Latitud { get; set; } public string Longitud { get; set; } public string Nombre { get; set; } public string Altura { get; set; } public string Barrio { get; set; } public Ubicacion() { } } I need to take that XML file and create an object with those values... Does somebody know a quick way to do it? with C#? I have been trying this but is not working at all... XElement dir = XElement.Parse(text); Ubicacion informacion = from d in dir.Elements("calle"). select new Ubicacion { Longitud = d.Element("longitud").Value, Latitud = d.Element("latitud").Value, Altura = d.Element("altura").Value, Nombre = d.Element("nombre").Value, Barrio = d.Element("barrio").Value, }; return informacion.Cast<Ubicacion>(); } Any ideas? Thanks!!!

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  • How to avoid "The name 'ConfigurationManager' does not exist in the current context" error?

    - by 5YrsLaterDBA
    I am using VS2008. I have a project connect with a database and the connection string is read from App.config via ConfigurationManager. We are using L2E. Now I added a helper project, AndeDataViewer, to have a simple UI to display data from the database for testing/verification purpose. I don't want to create another set of Entity Data Model in the helper project. I just added all related files as a link in the new helper project. When I compile, I got the following error: Error 15 The name 'ConfigurationManager' does not exist in the current context C:\workspace\SystemSoftware\SystemSoftware\src\systeminfo\RuntimeInfo.cs 24 40 AndeDataViewer I think I may need to add another project setting/config related file's link to the helper project from the main project? There is no App.config file in the new helper project. But it looks I cannot add that file's link to the helper project. Any ideas?

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  • Linq2XML not getting content of a node that contains html tags

    - by Dante
    Hi, I have an XML file that I'm trying to parse with Linq2XML. One of the nodes contains a bit of html, that I cannot retrieve. The XML resembles to: <?xml version="1.0" encoding="ISO-8859-1"?> <root> <image><img src="/Images/m1cznk4a6fh7.jpg" /></image> <contentType>Banner</contentType> </root> The code is: XDocument document = XDocument.Parse(content.XML); XElement imageElement = document.Descendants("image").SingleOrDefault(); image = imageElement.Value; // Doesn't get the content, while if I specify .Descendants("contentType") it works Any ideas? Thank you in advance

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  • Add WhereParameters to LinqDataSource in Selecting event

    - by Steven
    I have a repeater using a LinqDataSource as a data source. When a query string is entered, I'd like to filter the results, but ONLY when a query string is entered. If there is no query string, the results should not be filtered, all results should be returned. I'm trying to add a WhereParameter to my LinqDataSource in the Selecting event of the LinqDataSource, but it's not working. Here's my code: protected void ldsImages_Selecting(object sender, LinqDataSourceSelectEventArgs e) { if (Request.QueryString["id"] != null) { e.WhereParameters.Add("ImageTypeID", Request.QueryString["id"]); } }

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  • XElement Path Validation

    - by cw
    Hello, I am trying to validate Elements and Attributes exist in an XElement. Basically, I was wondering if anyone had a generic way to check if a give path is null. I don't have access to System.Xml.XPath (doing this for compact framework). Basically what I have is: <root value"1000"> <element1>test<element1> <element2>1<element2> .... <element30> <subElement1>stuff</subElement1> </element30> </root> Now I know you can "if this is null do this and that". But since there is upwards of 30 elements that can be under root, which are optional elements, I need a way to grab the value if it exists and convert it to the correct type (which I know) in a nice compact way. Any suggestions?

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  • jQuery find file extension (from string)

    - by SoulieBaby
    Hi all, I was wondering if it was possible for jQuery to find a file extension based on a returned string? A filename (string) will be passed to a function (openFile) and I wanted that function to do different things based on what file has been passed through, it could be image files or pdf files. function openFile(file) { //if .jpg/.gif/.png do something //if .zip/.rar do something else //if .pdf do something else }; I've been looking for something that will find the file's extension but I can't seem to find anything.

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  • Dictionary<string,string> to Dictionary<Control,object> using IEnumerable<T>.Select()

    - by abatishchev
    I have a System.Collections.Generic.Dictionary<string, string> containing control ID and appropriate data column to data bind: var dic = new Dictionary<string, string> { { "Label1", "FooCount" }, { "Label2", "BarCount" } }; I use it that way: var row = ((DataRowView)FormView1.DataItem).Row; Dictionary<Control, object> newOne = dic.ToDictionary( k => FormView1.FindControl(k.Key)), k => row[k.Value]); So I'm using IEnumerable<T>.ToDictionary(Func<T>, Func<T>). Is it possbile to do the same using IEnumerable<T>.Select(Func<T>) ?

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  • VS2010 Using SQL Server 2000

    - by Chris M
    Is there a way to use the SQL Model (dbml) builder in VS2010 using SQLServer2000? It works fine in VSExpress2008 + VS2008 but throws an "Upgrade SQL to 2005" error in VS2010 which seems a tad unreasonable.

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  • Error compiling Visual Studio 2010 EditorClassifier Extension Template

    - by nick.ueda
    I'm trying to create an Editor Classifier Template project and run it. When I attempt to build I get an error message stating: "Error trying to read the VSIX manifest file 'extension.vsixmanifest'. Exception has been thrown by target of invocation." Any thoughts? I've tried googling this but didn't have any luck. I am working with Visual Studio 2010 Ultimate and the VS 2010 SDK Beta 1. Thanks, Nick

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  • the best way to convert delimited to fixed width

    - by ehosca
    What is the BEST way to convert this : FirstName,LastName,Title,BirthDate,HireDate,City,Region Nancy,Davolio,Sales Representative,1948-12-08,1992-05-01,Seattle,WA Andrew,Fuller,Vice President Sales,1952-02-19,1992-08-14,Tacoma,WA Janet,Leverling,Sales Representative,1963-08-30,1992-04-01,Kirkland,WA Margaret,Peacock,Sales Representative,1937-09-19,1993-05-03,Redmond,WA Steven,Buchanan,Sales Manager,1955-03-04,1993-10-17,London,NULL Michael,Suyama,Sales Representative,1963-07-02,1993-10-17,London,NULL Robert,King,Sales Representative,1960-05-29,1994-01-02,London,NULL Laura,Callahan,Inside Sales Coordinator,1958-01-09,1994-03-05,Seattle,WA Anne,Dodsworth,Sales Representative,1966-01-27,1994-11-15,London,NULL to this : FirstName LastName Title BirthDate HireDate City Region ---------- -------------------- ------------------------------ ----------- ---------- --------------- --------------- Nancy Davolio Sales Representative 1948-12-08 1992-05-01 Seattle WA Andrew Fuller Vice President, Sales 1952-02-19 1992-08-14 Tacoma WA Janet Leverling Sales Representative 1963-08-30 1992-04-01 Kirkland WA Margaret Peacock Sales Representative 1937-09-19 1993-05-03 Redmond WA Steven Buchanan Sales Manager 1955-03-04 1993-10-17 London NULL Michael Suyama Sales Representative 1963-07-02 1993-10-17 London NULL Robert King Sales Representative 1960-05-29 1994-01-02 London NULL Laura Callahan Inside Sales Coordinator 1958-01-09 1994-03-05 Seattle WA Anne Dodsworth Sales Representative 1966-01-27 1994-11-15 London NULL

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  • Can I remove items from a ConcurrentDictionary from within an enumeration loop of that dictionary?

    - by the-locster
    So for example: ConcurrentDictionary<string,Payload> itemCache = GetItems(); foreach(KeyValuePair<string,Payload> kvPair in itemCache) { if(TestItemExpiry(kvPair.Value)) { // Remove expired item. Payload removedItem; itemCache.TryRemove(kvPair.Key, out removedItem); } } Obviously with an ordinary Dictionary this will throw an exception because removing items changes the dictionary's internal state during the life of the enumeration. It's my understanding that this is not the case for a ConcurrentDictionary as the provided IEnumerable handles internal state changing. Am I understanding this right? Is there a better pattern to use?

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  • How to perform a Linq2Sql query on the following dataset

    - by Bas
    I have the following tables: Person(Id, FirstName, LastName) { (1, "John", "Doe"), (2, "Peter", "Svendson") (3, "Ola", "Hansen") (4, "Mary", "Pettersen") } Sports(Id, Name) { (1, "Tennis") (2, "Soccer") (3, "Hockey") } SportsPerPerson(Id, PersonId, SportsId) { (1, 1, 1) (2, 1, 3) (3, 2, 2) (4, 2, 3) (5, 3, 2) (6, 4, 1) (7, 4, 2) (8, 4, 3) } Looking at the tables, we can conclude the following facts: John plays Tennis John plays Hockey Peter plays Soccer Peter plays Hockey Ola plays Soccer Mary plays Tennis Mary plays Soccer Mary plays Hockey Now I would like to create a Linq2Sql query which retrieves the following: Get all Persons who play Hockey and Soccer Executing the query should return: Peter and Mary Anyone has any idea's on how to approach this in Linq2Sql?

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  • How do you cast a LinqToSql Table<TEntity> as a Table<IEntity> where TEntity : IEntity?

    - by DanM
    I'm trying to use DbLinq with a SQLite database, but I'm running into a problem when I try to cast an ITable as a Queryable<TEntity>. There is a known bug in DbLinq (Issue 211), which might be the source of my problem, but I wanted to make sure my code is sound and, if it is, find out if there might be something I can do to work around the bug. Here is the generic repository method that attempts to do the cast: public IQueryable<TEntity> GetAll() { return Table.Cast<TEntity>(); // Table is an ITable } This compiles, but if I pass in the interface IPerson for TEntity and the type of the entities in the table is Person (where Person : IPerson), I'm getting this error from DbLinq: S0133: Implement QueryMethod Queryable.Cast. Why am I trying to do this? I have a library project that doesn't know the type of the entity until runtime, but it does know the interface for the entity. So, I'm trying to cast to the interface type so that my library project can consume the data. Questions: Am I attempting an impossible cast or is this definitely a bug in DbLinq? How else could I go about solving my problem?

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  • Is there a way to create a SyndicationFeed from a String?

    - by Roberto Bonini
    Hi, I'm trying to recreate a SyndicationFeed object (System.ServiceModel.Syndication) from XML data that has been stored locally. If I were working with XMLDocument, this would be easy.I'd call LoadXml(string). The SyndicationFeed will only load from an XMLReader. The XMLReader will only take a Stream or another XMLReader or a TextReader. Since XMLDocument will load a string, I've tried to do this as follows (in the form of a Extension Method): public static SyndicationFeed ToSyndicationFeed(this XmlDocument document) { Stream thestream = Stream.Null; XmlWriter thewriter = XmlWriter.Create(thestream); document.WriteTo(thewriter); thewriter.Flush(); XmlReader thereader = XmlReader.Create(thestream); SyndicationFeed thefeed = SyndicationFeed.Load(thereader); return thefeed; } I can't get this to work. The Stream is always empty even though the XMLDocument is populated with the Feed to be loaded into the SyndicationFeed. Any help or pointers you can give would be most helpful. Thanks, Roberto

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  • Linq2Sql relationships and WCF serialization problem

    - by devmania
    hi, here is my scenario i got Table1 id name Table2 id family fid with one to many relationship set between Table1. id and Table2.fid now here is my WCF service Code [OperationContract] public List<Table1> GetCustomers(string numberToFetch) { using (DataClassesDataContext context = new DataClassesDataContext()) { return context.Table1s.Take(int.Parse(numberToFetch)).ToList( ); } } and my ASPX page Code <body xmlns:sys="javascript:Sys" xmlns:dataview="javascript:Sys.UI.DataView"> <div id="CustomerView" class="sys-template" sys:attach="dataview" dataview:autofetch="true" dataview:dataprovider="Service2.svc" dataview:fetchParameters="{{ {numberToFetch: 2} }}" dataview:fetchoperation="GetCustomers"> <ul> <li>{{family}}</li> </ul> </div> though i set serialization mode to Unidirectional in Linq2Sql designer i am not able to get the family value and all what i get is this in firebug {"d":[{"__type":"Table1:#","id":1,"name":"asd"},{"__type":"Table1:#","id":2,"name":"wewe"}]} any help would be totally appreciated

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  • retrieve newly inserted record ID with Linq2SQL

    - by devmania
    hi, i am using the following private BlogDataContext db = new BlogDataContext (); article.Created = DateTime.UtcNow; article.Modified = DateTime.UtcNow; db.Articles.InsertOnSubmit(article); db.SubmitChanges( ); int id = article.Id; i am wondering is this save, i mean will it give me the Id of the article user inserted or will there be case of concurrences if another user update the article in fraction of second after this user ? thanks in advanced.

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  • speed: XmlTextReader vs LinqtoXml

    - by Michel
    Hi, i'm about to read some xml (who isn't :-)) This time however it's a lot of data: about 30.000 records with 5 properties, all in one file. Till now i've always read that the XmlTextReader is the fastest way to read xml data, but now there also is the (nice sytax of) linqtoXml. Does anybody know any performance issues, or that there aren't any, with LinqToXml? Michel

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