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  • Is writing eSQL database agnostic?

    - by Robert Koritnik
    Using EF we can use LINQ to read data which is rather simple (especialy using fluent calls), but we have less control unless we write eSQL on our own. Is writing eSQL database actually data store independant code? So if we decide to change data store, can the same statements still be used? Is writing eSQL strings in your code pose any serious security threats similar to writing TSQL statements in plain strings? So we moved to SPs. Could we still mode eSQL scripts outside of code as well and use some other technique to make them a bit more secure?

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  • Retrieve EF4 POCOs using WCF REST services starter kit

    - by muruge
    I am using WCF REST service (GET method) to retrieve my EF4 POCOs. The service seem to work just fine. When I query the uri in my browser I get the results as expected. In my client application I am trying to use WCF REST Starter Kit's HTTPExtension method - ReadAsDataContract() to convert the result back into my POCO. This works fine when the POCO's navigation property is a single object of related POCO. The problem is when the navigation property is a collection of related POCOs. The ReadAsDataContract() method throws an exception with message "Object reference not set to an instance of an object." Below are my POCOs. [DataContract(Namespace = "", Name = "Trip")] public class Trip { [DataMember(Order = 1)] public virtual int TripID { get; set; } [DataMember(Order = 2)] public virtual int RegionID { get; set; } [DataMember(Order = 3)] public virtual System.DateTime BookingDate { get; set; } [DataMember(Order = 4)] public virtual Region Region { // removed for brevity } } [DataContract(Namespace = "", Name = "Region")] public class Region { [DataMember(Order = 1)] public virtual int RegionID { get; set; } [DataMember(Order = 2)] public virtual string RegionCode { get; set; } [DataMember(Order = 3)] public virtual FixupCollection<Trip> Trips { // removed for brevity } } [CollectionDataContract(Namespace = "", Name = "{0}s", ItemName = "{0}")] [Serializable] public class FixupCollection<T> : ObservableCollection<T> { protected override void ClearItems() { new List<T>(this).ForEach(t => Remove(t)); } protected override void InsertItem(int index, T item) { if (!this.Contains(item)) { base.InsertItem(index, item); } } } And this is how I am trying retrieve a Region POCO. static void GetRegion() { string uri = "http://localhost:8080/TripService/Regions?id=1"; HttpClient client = new HttpClient(uri); using (HttpResponseMessage response = client.Get(uri)) { Region region; response.EnsureStatusIsSuccessful(); try { region = response.Content.ReadAsDataContract<Region>(); // this line throws exception because Region returns a collection of related trips Console.WriteLine(region.RegionName); } catch (Exception ex) { Console.WriteLine(ex.Message); } } } Would appreciate any pointers.

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  • .DBML file and LINQ to SQL

    - by Rishabh Ohri
    In my DBML file I have mapped some tables and stored procedures, and the stored procedures return type is ISingleResult . T is some mapped table. But I want to take the data into my own created entities rather than LINQ to SQL created entites. The entites created by me are also the same as the mapped table entities and their use lies when we send data across the a web service. So , how can I proceed by creating a wrapper around the DBML file so that I always get data in my own created entites.

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  • IEditableCollectionView.AddNew() Throwing ArgumentNullException

    - by Eugarps
    In the context of Silverlight RIA using DomainContext and, the code as follows: private void AddProductButton_Click(object sender, RoutedEventArgs e) { var target = (Web.LocatorProduct)((IEditableCollectionView)ProductSource.DataView).AddNew(); target.Locator = LocatorID; target.Product = NewProduct.Text.ToUpper(); ((IEditableCollectionView)ProductSource.DataView).CommitNew(); } Is throwing ArgumentNullException in AddNew(), CreateIdentity() further up on the stack (a generated method) due to product being null. Product and LocatorID are, in combination, the primary key. I'm guessing that EF is not allowing me to generate a new item without meeting database contraints? How does this make sense if I need to obtain a primary key from the user? I have control over all tiers of the application, so suggestions on database design if needed are also welcomed.

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  • EF OrderBy method doesn't work with joins

    - by dudeNumber4
    Following works (ordered by name): from t in context.Table1.OrderBy( "it.Name" ) select t This doesn't work (no ordering): from t in context.Table1.OrderBy( "it.Name" ) join t2 in context.Table2 on t.SomeId equals t2.SomeId select t Nor does this (trying to reference the parent table to order): from t in context.Table1 join t2 in context.Table2.OrderBy( "it.Table1.Name" ) on t.SomeId equals t2.SomeId select t Nor does this (trying to order on the child table): from t in context.Table1 join t2 in context.Table2.OrderBy( "it.ChildName" ) on t.SomeId equals t2.SomeId select t How do I cause OrderBy not to be ignored while joining?

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  • L2E delete exception

    - by 5YrsLaterDBA
    I have following code to delete an user from database: try { var user = from u in db.Users where u.Username == username select u; if (user.Count() > 0) { db.DeleteObject(user.First()); db.SaveChanges(); } } but I got exception like this: at System.Data.Mapping.Update.Internal.UpdateTranslator.Update(IEntityStateManager stateManager, IEntityAdapter adapter) at System.Data.EntityClient.EntityAdapter.Update(IEntityStateManager entityCache) at System.Data.Objects.ObjectContext.SaveChanges(Boolean acceptChangesDuringSave) at System.Data.Objects.ObjectContext.SaveChanges() at MyCompany.SystemSoftware.DQMgr.User.DeleteUser(String username) in C:\workspace\SystemSoftware\SystemSoftware\src\dqm\User.cs:line 479 The Users table is referenced by few other tables. It is probably caused by the foreign key constraint?

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  • Why can't I see the 'dataset project' property in Visual Studio DataSet designer?

    - by Ryan
    Hi, I am trying to follow 'n tier app design' tutorials and they tell me to set the DataSet Project property from the Data Set Designer in VS, to split table adaptors and entities into seprate projects. I can't see that property! (I'm looking in the same place shown on the videos... all other properties match) Does anybody know why? The video is here http://windowsclient.net/learn/video.aspx?v=14625 (4:36 is where the property is set) I'm using VS c# 2008 Express, with SQL Server Express 2008. Thanks a lot for any help Ryan

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  • MVC ASP.NET, ObjectContext and Ajax. Weird Behaviour

    - by fabianadipolo
    Hi, i've been creating a web application in mvc asp.net. I have three different project/solutions. One solution contains the model in EF (DAL) and all the methods to add, update, delete and query the objects in the model, the objectcontext is managed here in a per request basis. Other solution contains a content management system in wich authorized users insert, delete, update and access objects through the DAL mentioned before. And the last solution contains the web page that is accessed by all users and where the only operations executed are selects, no update, inserts or deletes here. All the selects are executed against the DAL mentioned before (the first solution). The problem here is that i'm not sure whether an HttpContext lifespan ObjectContext is the best solution. I have a lot of ajax calls in my web app and i'm not sure if an httpcontext could interfere with the performance of the application. I've been noticed that in some cases, specially when someone is working in the content manager inserting, updating or deleting, when you try to click on any link of the user web application (the web app that is accessed by any user - the third one that i mentioned before) the web page freezes and it remains stucked transferring data. In order to stop that behaviour you have to stop and refresh or click several times on the link. Excuse me for my bad english. I hope you could understand and could help me to solve this issue. Thanx in advance.

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  • Linq 2 Sybase ASE database? What are the options?

    - by Scott Weinstein
    I have a need to query an existing Sybase ASE database and would like to use Linq syntax for my data retrival. I don't need write access, nor do I need the full set of Linq operators, just Select(), SelectMany(), Where(), and GroupJoin() What are options are available? In particular, I'm wondering about nHibernate and building a new Linq2Sybase provider based on the IQ toolkit.

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  • Linq query challenge

    - by vdh_ant
    My table structure is as follows: Person 1-M PesonAddress Person 1-M PesonPhone Person 1-M PesonEmail Person 1-M Contract Contract M-M Program Contract M-1 Organization At the end of this query I need a populated object graph where each person has their: PesonAddress's PesonPhone's PesonEmail's PesonPhone's Contract's - and this has its respective Program's Now I had the following query and I thought that it was working great, but it has a couple of problems: from people in ctx.People.Include("PersonAddress") .Include("PersonLandline") .Include("PersonMobile") .Include("PersonEmail") .Include("Contract") .Include("Contract.Program") where people.Contract.Any( contract => (param.OrganizationId == contract.OrganizationId) && contract.Program.Any( contractProgram => (param.ProgramId == contractProgram.ProgramId))) select people; The problem is that it filters the person to the criteria but not the Contracts or the Contract's Programs. It brings back all Contracts that each person has not just the ones that have an OrganizationId of x and the same goes for each of those Contract's Programs respectively. What I want is only the people that have at least one contract with an OrgId of x with and where that contract has a Program with the Id of y... and for the object graph that is returned to have only the contracts that match and programs within that contract that match. I kinda understand why its not working, but I don't know how to change it so it is working... This is my attempt thus far: from people in ctx.People.Include("PersonAddress") .Include("PersonLandline") .Include("PersonMobile") .Include("PersonEmail") .Include("Contract") .Include("Contract.Program") let currentContracts = from contract in people.Contract where (param.OrganizationId == contract.OrganizationId) select contract let currentContractPrograms = from contractProgram in currentContracts let temp = from x in contractProgram.Program where (param.ProgramId == contractProgram.ProgramId) select x where temp.Any() select temp where currentContracts.Any() && currentContractPrograms.Any() select new Person { PersonId = people.PersonId, FirstName = people.FirstName, ..., ...., MiddleName = people.MiddleName, Surname = people.Surname, ..., ...., Gender = people.Gender, DateOfBirth = people.DateOfBirth, ..., ...., Contract = currentContracts, ... }; //This doesn't work But this has several problems (where the Person type is an EF object): I am left to do the mapping by myself, which in this case there is quite a lot to map When ever I try to map a list to a property (i.e. Scholarship = currentScholarships) it says I can't because IEnumerable is trying to be cast to EntityCollection Include doesn't work Hence how do I get this to work. Keeping in mind that I am trying to do this as a compiled query so I think that means anonymous types are out.

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  • ADO.NET Known Issues?

    - by Israel Rodriguez
    So, I'm starting a new Project in my company, and it's kinda big. We are going to use .NET 3.5, and I wish to known if there are any know bugs or perfomance issues that could give weird behaviour for my project? I'm reading some things about EFv4 and all they say is that EFv3.5 have too many problems. After all, what's the best and fastest way, ADO.NET Entities or extract the data from my DB directly to a DataReader? The EF Oracle provider is stable? The project will be .NET 3.5 and Oracle.

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  • How can I handle UTF-8 while posting to a vBulletin board with WWW::Mechanize?

    - by MrMirror
    I have a problem with some automating posting to bulletin board... If I send the posting form to the vBulletin board, I get corrupted entities. Feel free to copy-paste the script and try it... It looks like the board's expecting some decoded utf8, but if I send the message decoded the entities are still wrong. #!/usr/bin/perl use strict; use warnings; use WWW::Mechanize; use Digest::MD5 qw(md5_hex); my $mech = WWW::Mechanize->new(); my $base_url = 'http://www.boerse.bz/'; my $username = 'MrMirror'; my $password = 'test'; $mech->get($base_url); print "Login\n"; $mech->form_number(1); $mech->field('vb_login_username' => $username); $mech->field('vb_login_password' => $password); $mech->field('vb_login_md5password' => md5_hex($password)); $mech->field('vb_login_md5password_utf' => md5_hex($password)); $mech->submit(); unless ($mech->content() =~ m!Weiterleitung!gi) { print "No Rediction!\n"; exit; } print "Redict\n"; $mech->get($base_url); unless ($mech->content() =~ m!Logout!gi) { print "Login Failed!\n"; exit; } $mech->get($base_url .'/newthread.php?do=newthread&f=173'); $mech->form_number(3); $mech->field('subject' => 'MrMirror makes some testing ä ö ü ß'); $mech->field('message' => "ä ö ü ß"); ### everything allright here $mech->dump_forms(); ### preview submit, don't wanna spam around ;) $mech->click('preview'); print "\n\n\n---------------------------------------------------------------------\n\n\n"; ### same form, wrong entities :( $mech->dump_forms();

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  • How does TransactionScope guarantee data integrity across multiple databases?

    - by Bas Smit
    Hey guys, Can someone tell me the principle of how TransactionScope guarantees data integrity across multiple databases? I imagine it first sends the commands to the databases and then waits for the databases to respond before sending them a message to apply the command sent earlier. However when execution is stopped abruptly when sending those apply messages we could still end up with a database that has applied the command and one that has not. Can anyone shed some light on this? Edit: I guess what Im asking is can I rely on TransactionScope to guarantee data integrity when writing to multiple databases in case of a power outage or a sudden shutdown. Thanks, Bas Example: using(var scope=new TransactionScope()) { using (var context = new FirstEntities()) { context.AddToSomethingSet(new Something()); context.SaveChanges(); } using (var context = new SecondEntities()) { context.AddToSomethingElseSet(new SomethingElse()); context.SaveChanges(); } scope.Complete(); }

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  • Linq guru - filtering related entities...

    - by vdh_ant
    My table structure is as follows: Person 1-M PesonAddress Person 1-M PesonPhone Person 1-M PesonEmail Person 1-M Contract Contract M-M Program Contract M-1 Organization At the end of this query I need a populated object graph where each person has their: PesonAddress's PesonPhone's PesonEmail's PesonPhone's Contract's - and this has its respective Program's Now I had the following query and I thought that it was working great, but it has a couple of problems: from people in ctx.People.Include("PersonAddress") .Include("PersonLandline") .Include("PersonMobile") .Include("PersonEmail") .Include("Contract") .Include("Contract.Program") where people.Contract.Any( contract => (param.OrganizationId == contract.OrganizationId) && contract.Program.Any( contractProgram => (param.ProgramId == contractProgram.ProgramId))) select people; The problem is that it filters the person to the criteria but not the Contracts or the Contract's Programs. It brings back all Contracts that each person has not just the ones that have an OrganizationId of x and the same goes for each of those Contract's Programs respectively. What I want is only the people that have at least one contract with an OrgId of x with and where that contract has a Program with the Id of y... and for the object graph that is returned to have only the contracts that match and programs within that contract that match. I kinda understand why its not working, but I don't know how to change it so it is working... This is my attempt thus far: from people in ctx.People.Include("PersonAddress") .Include("PersonLandline") .Include("PersonMobile") .Include("PersonEmail") .Include("Contract") .Include("Contract.Program") let currentContracts = from contract in people.Contract where (param.OrganizationId == contract.OrganizationId) select contract let currentContractPrograms = from contractProgram in currentContracts let temp = from x in contractProgram.Program where (param.ProgramId == contractProgram.ProgramId) select x where temp.Any() select temp where currentContracts.Any() && currentContractPrograms.Any() select new Person { PersonId = people.PersonId, FirstName = people.FirstName, ..., ...., MiddleName = people.MiddleName, Surname = people.Surname, ..., ...., Gender = people.Gender, DateOfBirth = people.DateOfBirth, ..., ...., Contract = currentContracts, ... }; //This doesn't work But this has several problems (where the Person type is an EF object): I am left to do the mapping by myself, which in this case there is quite a lot to map When ever I try to map a list to a property (i.e. Scholarship = currentScholarships) it says I can't because IEnumerable is trying to be cast to EntityCollection Include doesn't work Hence how do I get this to work. Keeping in mind that I am trying to do this as a compiled query so I think that means anonymous types are out.

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  • MVC and repository pattern data effeciency

    - by Shawn Mclean
    My project is structured as follows: DAL public IQueryable<Post> GetPosts() { var posts = from p in context.Post select p; return posts; } Service public IList<Post> GetPosts() { var posts = repository.GetPosts().ToList(); return posts; } //Returns a list of the latest feeds, restricted by the count. public IList<PostFeed> GetPostFeeds(int latestCount) { List<Post> post - GetPosts(); //CODE TO CREATE FEEDS HERE return feeds; } Lets say the GetPostFeeds(5) is supposed to return the 5 latest feeds. By going up the list, doesn't it pull down every single post from the database from GetPosts(), just to extract 5 from it? If each post is say 5kb from the database, and there is 1 million records. Wont that be 5GB of ram being used per call to GetPostFeeds()? Is this the way it happens? Should I go back to my DAL and write queries that return only what I need?

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  • MVC 2.0 - JqGrid Sorting with Mulitple Tables

    - by Billy Logan
    I am in the process of implementing the jqGrid and would like to be able to use the sorting functionality. I have run into some issues with sorting columns that are related to the base table. Here is the script to load the grid: public JsonResult GetData(GridSettings grid) { try { using (IWE dataContext = new IWE()) { var query = dataContext.LKTYPE.Include("VWEPICORCATEGORY").AsQueryable(); ////sorting query = query.OrderBy<LKTYPE>(grid.SortColumn, grid.SortOrder); //count var count = query.Count(); //paging var data = query.Skip((grid.PageIndex - 1) * grid.PageSize).Take(grid.PageSize).ToArray(); //converting in grid format var result = new { total = (int)Math.Ceiling((double)count / grid.PageSize), page = grid.PageIndex, records = count, rows = (from host in data select new { TYPE_ID = host.TYPE_ID, TYPE = host.TYPE, CR_ACTIVE = host.CR_ACTIVE, description = host.VWEPICORCATEGORY.description }).ToArray() }; return Json(result, JsonRequestBehavior.AllowGet); } } catch (Exception ex) { //send the error email ExceptionPolicy.HandleException(ex, "Exception Policy"); } //have to return something if there is an issue return Json(""); } As you can see the description field is a part of the related table("VWEPICORCATEGORY") and the order by is targeted at LKTYPE. I am trying to figure out how exactly one goes about sorting that particular field or maybe even a better way to implement this grid using multiple tables and it's sorting functionality. Thanks in advance, Billy

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  • Efficiently Determine if EF 4 POCO Already in ObjectSet

    - by Eric J.
    I'm trying EF 4 with POCO's on a small project for the first time. In my Repository implementation, I want to provide a method AddOrUpdate that will add a passed-in POCO to the repository if it's new, else do nothing (as the updated POCO will be saved when SaveChanges is called). My first thought was to do this: public void AddOrUpdate(Poco p) { if (!Ctx.Pocos.Contains<Poco>(p)) { Ctx.Pocos.AddObject(p); } } However that results in a NotSupportedException as documented under Referencing Non-Scalar Variables Not Supported (bonus question: why would that not be supported?) Just removing the Contains part and always calling AddObject results in an InvalidStateException: An object with the same key already exists in the ObjectStateManager. The existing object is in the Unchanged state. An object can only be added to the ObjectStateManager again if it is in the added state. So clearly EF 4 knows somewhere that this is a duplicate based on the key. What's a clean, efficient way for the Repository to update Pocos for either a new or pre-existing object when AddOrUpdate is called so that the subsequent call to SaveChanges() will do the right thing? I did consider carrying an isNew flag on the object itself, but I'm trying to take persistence ignorance as far as practical.

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  • Custom model in ASP.NET MVC controller: Custom display message for Date DataType

    - by Rita
    Hi I have an ASP.NET MVC Page that i have to display the fields in customized Text. For that I have built a CustomModel RequestViewModel with the following fields. Description, Event, UsageDate Corresponding to these my custom Model has the below code. So that, the DisplayName is displayed on the ASP.NET MVC View page. Now being the Description and Event string Datatype, both these fields are displaying Custom DisplayMessage. But I have problem with Date Datatype. Instead of "Date of Use of Slides", it is still displaying UsageDate from the actualModel. Anybody faced this issue with DateDatatype? Appreciate your responses. Custom Model: [Required(ErrorMessage="Please provide a description")] [DisplayName("Detail Description")] [StringLength(250, ErrorMessage = "Description cannot exceed 250 chars")] // also need min length 30 public string Description { get; set; } [Required(ErrorMessage="Please specify the name or location")] [DisplayName("Name/Location of the Event")] [StringLength(250, ErrorMessage = "Name/Location cannot exceed 250 chars")] public string Event { get; set; } [Required(ErrorMessage="Please specify a date", ErrorMessageResourceType = typeof(DateTime))] [DisplayName("Date of Use of Slides")] [DataType(DataType.Date)] public string UsageDate { get; set; } ViewCode: <p> <%= Html.LabelFor(model => model.Description) %> <%= Html.TextBoxFor(model => model.Description) %> <%= Html.ValidationMessageFor(model => model.Description) %> </p> <p> <%= Html.LabelFor(model => model.Event) %> <%= Html.TextBoxFor(model => model.Event) %> <%= Html.ValidationMessageFor(model => model.Event) %> </p> <p> <%= Html.LabelFor(model => model.UsageDate) %> <%= Html.TextBoxFor(model => model.UsageDate) %> <%= Html.ValidationMessageFor(model => model.UsageDate) %> </p>

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  • Performing dynamic sorts on EF4 data

    - by Jaxidian
    I'm attempting to perform dynamic sorting of data that I'm putting into grids into our MVC UI. Since MVC is abstracted from everything else via WCF, I've created a couple utility classes and extensions to help with this. The two most important things (slightly simplified) are as follows: public static IQueryable<T> ApplySortOptions<T, TModel, TProperty>(this IQueryable<T> collection, IEnumerable<ISortOption<TModel, TProperty>> sortOptions) where TModel : class { var sortedSortOptions = (from o in sortOptions orderby o.Priority ascending select o).ToList(); var results = collection; foreach (var option in sortedSortOptions) { var currentOption = option; var propertyName = currentOption.Property.MemberWithoutInstance(); var isAscending = currentOption.IsAscending; if (isAscending) { results = from r in results orderby propertyName ascending select r; } else { results = from r in results orderby propertyName descending select r; } } return results; } public interface ISortOption<TModel, TProperty> where TModel : class { Expression<Func<TModel, TProperty>> Property { get; set; } bool IsAscending { get; set; } int Priority { get; set; } } I've not given you the implementation for MemberWithoutInstance() but just trust me in that it returns the name of the property as a string. :-) Following is an example of how I would consume this (using a non-interesting, basic implementation of ISortOption<TModel, TProperty>): var query = from b in CurrentContext.Businesses select b; var sortOptions = new List<ISortOption<Business, object>> { new SortOption<Business, object> { Property = (x => x.Name), IsAscending = true, Priority = 0 } }; var results = query.ApplySortOptions(sortOptions); As I discovered with this question, the problem is specific to my orderby propertyName ascending and orderby propertyName descending lines (everything else works great as far as I can tell). How can I do this in a dynamic/generic way that works properly?

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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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  • EF4 cross database relationships

    - by Daniel
    Hello all, I was wondering if EF4 support cross-databse relationships? For instance: db1 Author Id Name db2 Posts Id Content db1.Author.Id What ideally I need to do to get this relation in my ef4 model? Do you guys have any idea? Thanks

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