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  • Is there such a thing as a MemberExpression that handles a many-to-many relationship?

    - by Jaxidian
    We're trying to make it easy to write strongly-typed code in all areas of our system, so rather than setting var sortColumn = "FirstName" we'd like to say sortOption = (p => p.FirstName). This works great if the sortOption is of type Expression<Func<Person, object>> (we actually use generics in our code but that doesn't matter). However, we run into problems for many-to-many relationships because this notation breaks down. Consider this simple code: internal class Business { public IQueryable<Address> Addresses { get; set; } public string Name { get; set; } } internal class Address { public State MyState { get; set; } } internal class State { public string Abbreviation { get; set; } public int StateID { get; set; } } Is it possible to have this sort of MemberExpression to identify the StateID column off of a business? Again, the purpose of using this is not to return a StateID object, it's to just identify that property off of that entity (for sorting, filtering, and other purposes). It SEEMS to me that there should be some way to do this, even if it's not quite as pretty as foo = business.Addresses.SomeExtension(a => a.State.StateID);. Is this really possible? If more background is needed, take a look at this old question of mine. We've since updated the code significantly, but this should give you the general detailed idea of the context behind this question.

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  • How to Export data to Excel using LINQ to Entity?

    - by Rita
    Hi I have the data coming from Entity Data model table on my ASP.NET page. Now I have to export this data into Excel on button click. If it is using OLEDB, it is straight forward as it is here: http://csharp.net-informations.com/excel/csharp-excel-oledb-insert.htm Here is my function to read data from inquiries table: var model = from i in myEntity.Inquiries where i.User_Id == 5 orderby i.TX_Id descending select new { RequestID = i.TX_Id, CustomerName = i.CustomerMaster.FirstName, RequestDate = i.RequestDate, Email = i.CustomerMaster.MS_Id, DocDescription = i.Document.Description, ProductName = i.Product.Name

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  • LINQ to SQL - Save an entity without creating a new DataContext?

    - by aximili
    I get this error Cannot add an entity with a key that is already in use when I try to save an Item [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(Item item) { Global.DataContext.Items.Attach(item); Global.DataContext.SubmitChanges(); return View(item); } That's because I cannot attach the item to the static global DataContext. Is it possible to save an item without creating a new DataContext? (I am very new to LINQ)

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  • How do I merge a transient entity with a session using Castle ActiveRecordMediator?

    - by Daniel T.
    I have a Store and a Product entity: public class Store { public Guid Id { get; set; } public int Version { get; set; } public ISet<Product> Products { get; set; } } public class Product { public Guid Id { get; set; } public int Version { get; set; } public Store ParentStore { get; set; } public string Name { get; set; } } In other words, I have a Store that can contain multiple Products in a bidirectional one-to-many relationship. I'm sending data back and forth between a web browser and a web service. The following steps emulates the communication between the two, using session-per-request. I first save a new instance of a Store: using (new SessionScope()) { // this is data from the browser var store = new Store { Id = Guid.Empty }; ActiveRecordMediator.SaveAndFlush(store); } Then I grab the store out of the DB, add a new product to it, and then save it: using (new SessionScope()) { // this is data from the browser var product = new Product { Id = Guid.Empty, Name = "Apples" }); var store = ActiveRecordLinq.AsQueryable<Store>().First(); store.Products.Add(product); ActiveRecordMediator.SaveAndFlush(store); } Up to this point, everything works well. Now I want to update the Product I just saved: using (new SessionScope()) { // data from browser var product = new Product { Id = Guid.Empty, Version = 1, Name = "Grapes" }; var store = ActiveRecordLinq.AsQueryable<Store>().First(); store.Products.Add(product); // throws exception on this call ActiveRecordMediator.SaveAndFlush(store); } When I try to update the product, I get the following exception: a different object with the same identifier value was already associated with the session: 00000000-0000-0000-0000-000000000000, of entity:Product" As I understand it, the problem is that when I get the Store out of the database, it also gets the Product that's associated with it. Both entities are persistent. Then I tried to save a transient Product (the one that has the updated info from the browser) that has the same ID as the one that's already associated with the session, and an exception is thrown. However, I don't know how to get around this problem. If I could get access to a NHibernate.ISession, I could call ISession.Merge() on it, but it doesn't look like ActiveRecordMediator has anything similar (SaveCopy threw the same exception). Does anyone know the solution? Any help would be greatly appreciated!

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  • how to insert using linq to entity foreign key value?

    - by Gamble
    I have a table (TestTable) for example: ID Name Parentid (FK) and I would like to insert a new record like ID(1) Name(Test) ParentID(5) FK. How can insert a new record into TestTable with linq to entity? var testTable = new TestTable(); testTable.ID = 1; testTable.Name = "TestName"; testTable ... thank you for the working example.

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  • How do I check if a Linq to SQL entity has grandchildren?

    - by EdenMachine
    How can I find out if a Linq to SQL entity has grandchildren or not? Pseudo-code below: Return From p In dc.Processes Where p.Signers.Count > 0 and p.Signers.Signatures.Count > 0 Obviously I can't run the code above but I need to make sure that all the returning Processes have at least one Signer and that all of those Signers have at least one Signature. TIA!

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  • Is a many-to-many relationship with extra fields the right tool for my job?

    - by whichhand
    Previously had a go at asking a more specific version of this question, but had trouble articulating what my question was. On reflection that made me doubt if my chosen solution was correct for the problem, so this time I will explain the problem and ask if a) I am on the right track and b) if there is a way around my current brick wall. I am currently building a web interface to enable an existing database to be interrogated by (a small number of) users. Sticking with the analogy from the docs, I have models that look something like this: class Musician(models.Model): first_name = models.CharField(max_length=50) last_name = models.CharField(max_length=50) dob = models.DateField() class Album(models.Model): artist = models.ForeignKey(Musician) name = models.CharField(max_length=100) class Instrument(models.Model): artist = models.ForeignKey(Musician) name = models.CharField(max_length=100) Where I have one central table (Musician) and several tables of associated data that are related by either ForeignKey or OneToOneFields. Users interact with the database by creating filtering criteria to select a subset of Musicians based on data the data on the main or related tables. Likewise, the users can then select what piece of data is used to rank results that are presented to them. The results are then viewed initially as a 2 dimensional table with a single row per Musician with selected data fields (or aggregates) in each column. To give you some idea of scale, the database has ~5,000 Musicians with around 20 fields of related data. Up to here is fine and I have a working implementation. However, it is important that I have the ability for a given user to upload there own annotation data sets (more than one) and then filter and order on these in the same way they can with the existing data. The way I had tried to do this was to add the models: class UserDataSets(models.Model): user = models.ForeignKey(User) name = models.CharField(max_length=100) description = models.CharField(max_length=64) results = models.ManyToManyField(Musician, through='UserData') class UserData(models.Model): artist = models.ForeignKey(Musician) dataset = models.ForeignKey(UserDataSets) score = models.IntegerField() class Meta: unique_together = (("artist", "dataset"),) I have a simple upload mechanism enabling users to upload a data set file that consists of 1 to 1 relationship between a Musician and their "score". Within a given user dataset each artist will be unique, but different datasets are independent from each other and will often contain entries for the same musician. This worked fine for displaying the data, starting from a given artist I can do something like this: artist = Musician.objects.get(pk=1) dataset = UserDataSets.objects.get(pk=5) print artist.userdata_set.get(dataset=dataset.pk) However, this approach fell over when I came to implement the filtering and ordering of query set of musicians based on the data contained in a single user data set. For example, I could easily order the query set based on all of the data in the UserData table like this: artists = Musician.objects.all().order_by(userdata__score) But that does not help me order by the results of a given single user dataset. Likewise I need to be able to filter the query set based on the "scores" from different user data sets (eg find all musicians with a score 5 in dataset1 and < 2 in dataset2). Is there a way of doing this, or am I going about the whole thing wrong?

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  • Best practice? - Array/Dictionary as a Core Data Entity Attribute

    - by Run Loop
    I am new to Core Data. I have noticed that collection types are not available as attribute types and would like to know what the most efficient way is of storing array/dictionary type data as an attribute (e.g. the elements that make up an address like street, city, etc. does not require a separate entity and is more conveniently stored as a dictionary/array than separate attributes/fields). Thank you.

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  • I have a feeling that adding fields marked with @Transient annotation to entity is very bug-prone. A

    - by Roman
    I have some philosophical feeling that adding to an entity fields which doesn't mapped to the DB is a wrong way of solving problems. But are there any concrete situations where using @Transient fields leads to implicit and hard fixing problems? For example, is it possible that adding/removing 2nd level cache will break our app when there are @Transient fields in our entities?

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  • How to get HTML5 canvas text to show html entity?

    - by mrollinsiv
    I'm parsing an xml file that stores image/caption data both of which I need to display on my canvas. However occasionally there's an entity in the file and when drawing the text to the canvas it interprets it as flat text. How can i get &copy; to show up as © on the canvas? Is this even possible, or does anyone know of a good work around?

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  • How to select with Linq to Entity from one table with two different variables?

    - by George
    I have a table where I have items under two different types as you can see below: How can I select from this table with Linq to Entity to get the result with two variables? where ItemType = Type1 and ItemType == Type2 .... select new {typeOne == "", typeTwo == ""}; ID ItemName ItemType 1 ItemOne Type1 2 ItemTwo Type1 3 ItemThree Type1 4 ItemFour Type1 5 ItemTFive Type2 6 ItemSix Type2 7 ItemSeven Type2 8 ItemEight Type2

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  • Hibernate fails with NullPointerException in EntityTuplizerFactory.constructTuplizer? Why?

    - by Subtwo
    I have a problem when I try to instantiate Hibernate and connect with a MySQL database (see error message below). Curiously enough the connection works fine using the exact same hibernate.cfg.xml file when running Junit tests but it refuses to work when run from Tomcat... I am starting to run out of ideas. Any clues or tip where to look? Caused by: org.hibernate.HibernateException: Unable to instantiate default tuplizer [org.hibernate.tuple.entity.DynamicMapEntityTuplizer] at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:110) at org.hibernate.tuple.entity.EntityTuplizerFactory.constructDefaultTuplizer(EntityTuplizerFactory.java:135) at org.hibernate.tuple.entity.EntityEntityModeToTuplizerMapping.(EntityEntityModeToTuplizerMapping.java:69) at org.hibernate.tuple.entity.EntityMetamodel.(EntityMetamodel.java:323) at org.hibernate.persister.entity.AbstractEntityPersister.(AbstractEntityPersister.java:456) at org.hibernate.persister.entity.SingleTableEntityPersister.(SingleTableEntityPersister.java:131) at org.hibernate.persister.PersisterFactory.createClassPersister(PersisterFactory.java:84) at org.hibernate.impl.SessionFactoryImpl.(SessionFactoryImpl.java:267) at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1341) at se.fmt.atlantism.util.HibernateUtil.buildSessionFactory(HibernateUtil.java:16) ... 38 more Caused by: java.lang.NullPointerException at org.hibernate.tuple.entity.EntityTuplizerFactory.constructTuplizer(EntityTuplizerFactory.java:107) ... 47 more

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  • How do I implement repository pattern and unit of work when dealing with multiple data stores?

    - by Jason
    I have a unique situation where I am building a DDD based system that needs to access both Active Directory and a SQL database as persistence. Initially this wasnt a problem because our design was setup where we had a unit of work that looked like this: public interface IUnitOfWork { void BeginTransaction() void Commit() } and our repositories looked like this: public interface IRepository<T> { T GetByID() void Save(T entity) void Delete(T entity) } In this setup our load and save would handle the mapping between both data stores because we wrote it ourselves. The unit of work would handle transactions and would contain the Linq To SQL data context that the repositories would use for persistence. The active directory part was handled by a domain service implemented in infrastructure and consumed by the repositories in each Save() method. Save() was responsible with interacting with the data context to do all the database operations. Now we are trying to adapt it to entity framework and take advantage of POCO. Ideally we would not need the Save() method because the domain objects are being tracked by the object context and we would just need to add a Save() method on the unit of work to have the object context save the changes, and a way to register new objects with the context. The new proposed design looks more like this: public interface IUnitOfWork { void BeginTransaction() void Save() void Commit() } public interface IRepository<T> { T GetByID() void Add(T entity) void Delete(T entity) } This solves the data access problem with entity framework, but does not solve the problem with our active directory integration. Before, it was in the Save() method on the repository, but now it has no home. The unit of work knows nothing other than the entity framework data context. Where should this logic go? I argue this design only works if you only have one data store using entity framework. Any ideas how to best approach this issue? Where should I put this logic?

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  • manyToOne is creating new products

    - by user788721
    I am trying to implement Sylius Cart Bundle, but every time I add a product to the cart, a new product is created. This is probably link to my line: cascade: ["persist", "remove"] In my YAML File: Pharmacie\FrontBundle\Entity\CartItem: type: entity table: app_cart_item manyToOne: produit: targetEntity: Pharmacie\FrontBundle\Entity\Product cascade: ["persist", "remove"] joinColumn: name: product_id referencedColumnName: id But if take it off, I get an error: A new entity was found through the relationship 'Pharmacie\FrontBundle\Entity\CartItem#produit' that was not configured to cascade persist operations for entity: 3test2. To solve this issue: Either explicitly call EntityManager#persist() on this unknown entity or configure cascade persist this association in the mapping for example @ManyToOne(..,cascade={"persist"}) According to the doctrine doc, this error occurs when you set a new object. But I am only getting an existing object By ID: $product = $this->getProductRepository()->find($productId); $item->setProduit($product); //this generates the error $item->setUnitPrice(5); //this works fine I don't understand why it's save as a new object. If I use merge instead of persist, I get the same error: A new entity was found through the relationship...

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  • ADO Entity Framework 4 to WPF Datagrid. DatagridComboBox nightmare.

    - by Jason
    The WPF datagrid -seems- like it's going to work, but the combobox implementation does not work straight from the designer. So I'm left wandering around in the XAML randomly changing things trying to get it to work. The problems are numerous. I want to display a foreign key relationship (with drop down) instead of a bunch of numbers for a selection. It seems like it shouldn't be this hard. I can get the right values to show up (their description instead of an ID), but the table freaks out thinking that all the values have been modified. If I select a drop down, it refuses to allow me to edit anything else. I want to chalk this up as a .NET bug, but since I'm new to WPF datagrids, it's probably just me. Here is the code. <DataGridComboBoxColumn Header="Make Up" ItemsSource="{Binding Source={StaticResource materialMakeUpTypesViewSource}}" DisplayMemberPath="Description" TextBinding="{Binding Path=MaterialMakeUpType.Description}" SelectedItemBinding="{Binding Path=MaterialMakeUpType.Description}" SelectedValueBinding="{Binding Path=MaterialMakeUpType.ID}" />

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  • Introduction to LinqPad Driver for StreamInsight 2.1

    - by Roman Schindlauer
    We are announcing the availability of the LinqPad driver for StreamInsight 2.1. The purpose of this blog post is to offer a quick introduction into the new features that we added to the StreamInsight LinqPad driver. We’ll show you how to connect to a remote server, how to inspect the entities present of that server, how to compose on top of them and how to manage their lifetime. Installing the driver Info on how to install the driver can be found in an earlier blog post here. Establishing connections As you click on the “Add Connection” link in the left pane you will notice that now it’s possible to build the data context automatically. The new driver appears as an option in the upper list, and if you pick it you will open a connection dialog that lets you connect to a remote StreamInsight server. The connection dialog lets you specify the address of the remote server. You will notice that it’s possible to pick up the binding information from the configuration file of the LinqPad application (which is normally in the same folder as LinqPad.exe and is called LinqPad.exe.config). In order for the context to be generated you need to pick an application from the server. The control is editable hence you can create a new application if you don’t want to make changes to an existing application. If you choose a new application name you will be prompted for confirmation before this gets created. Once you click OK the connection is created and you can start issuing queries against the remote server. If there’s any connectivity error the connection is marked with a red X and you can see the error message informing you what went wrong (i.e., the remote server could not be reached etc.). The context for remote servers Let’s take a look at what happens after we are connected successfully. Every LinqPad query runs inside a context – think of it as a class that wraps all the code that you’re writing. If you’re connecting to a live server the context will contain the following: The application object itself. All entities present in this application (sources, sinks, subjects and processes). The picture below shows a snapshot of the left pane of LinqPad after a successful connection. Every entity on the server has a different icon which will allow users to figure out its purpose. You will also notice that some entities have a string in parentheses following the name. It should be interpreted as such: the first name is the name of the property of the context class and the second name is the name of the entity as it exists on the server. Not all valid entity names are valid identifier names so in cases where we had to make a transformation you see both. Note also that as you hover over the entities you get IntelliSense with their types – more on that later. Remoting is not supported As you play with the entities exposed by the context you will notice that you can’t read and write directly to/from them. If for instance you’re trying to dump the content of an entity you will get an error message telling you that in the current version remoting is not supported. This is because the entity lives on the remote server and dumping its content means reading the events produced by this entity into the local process. ObservableSource.Dump(); Will yield the following error: Reading from a remote 'System.Reactive.Linq.IQbservable`1[System.Int32]' is not supported. Use the 'Microsoft.ComplexEventProcessing.Linq.RemoteProvider.Bind' method to read from the source using a remote observer. This basically tells you that you can call the Bind() method to direct the output of this source to a sink that has to be defined on the remote machine as well. You can’t bring the results to the LinqPad window unless you write code specifically for that. Compose queries You may ask – what's the purpose of all that? After all the same information is present in the EventFlowDebugger, why bother with showing it in LinqPad? First of all, What gets exposed in LinqPad is not what you see in the debugger. In LinqPad we have a property on the context class for every entity that lives on the server. Because LinqPad offers IntelliSense we in fact have much more information about the entity, and more importantly we can compose with that entity very easily. For example, let’s say that this code creates an entity: using (var server = Server.Connect(...)) {     var a = server.CreateApplication("WhiteFish");     var src = a         .DefineObservable<int>(() => Observable.Range(0, 3))         .Deploy("ObservableSource"); If later we want to compose with the source we have to fetch it and then we can bind something to     a.GetObservable<int>("ObservableSource)").Bind(... This means that we had to know a bunch of things about this: that it’s a source, that it’s an observable, it produces a result with payload Int32 and it’s named “ObservableSource”. Only the second and last bits of information are present in the debugger, by the way. As you type in the query window you see that all the entities are present, you get IntelliSense support for them and it’s much easier to make sense of what’s available. Let’s look at a scenario where composition is plausible. With the new programming model it’s possible to create “cold” sources that are parameterized. There was a way to accomplish that even in the previous version by passing parameters to the adapters, but this time it’s much more elegant because the expression declares what parameters are required. Say that we hover the mouse over the ThrottledSource source – we will see that its type is Func<int, int, IQbservable<int>> - this in effect means that we need to pass two int parameters before we can get a source that produces events, and the type for those events is int – in the particular case of my example I had the source produce a range of integers and the two parameters were the start and end of the range. So we see how a developer can create a source that is not running yet. Then someone else (e.g. an administrator) can pass whatever parameters appropriate and run the process. Proxy Types Here’s an interesting scenario – what if someone created a source on a server but they forgot to tell you what type they used. Worse yet, they might have used an anonymous type and even though they can refer to it by name you can’t figure out how to use that type. Let’s walk through an example that shows how you can compose against types you don’t need to have the definition of. This is how we can create a source that returns an anonymous type: Application.DefineObservable(() => Observable.Range(1, 10).Select(i => new { I = i })).Deploy("O1"); Now if we refresh the connection we can see the new source named O1 appear in the list. But what’s more important is that we now have a type to work with. So we can compose a query that refers to the anonymous type. var threshold = new StreamInsightDynamicDriver.TypeProxies.AnonymousType1_0<int>(5); var filter = from i in O1              where i > threshold              select i; filter.Deploy("O2"); You will notice that the anonymous type defined with this statement: new { I = i } can now be manipulated by a client that does not have access to it because the LinqPad driver has generated another type in its stead, named StreamInsightDynamicDriver.TypeProxies.AnonymousType1_0. This type has all the properties and fields of the type defined on the server, except in this case we can instantiate values and use it to compose more queries. It is worth noting that the same thing works for types that are not anonymous – the test is if the LinqPad driver can resolve the type or not. If it’s not possible then a new type will be generated that approximates the type that exists on the server. Control metadata In addition to composing processes on top of the existing entities we can do other useful things. We can delete them – nothing new here as we simply access the entities through the Entities collection of the application class. Here is where having their real name in parentheses comes handy. There’s another way to find out what’s behind a property – dump its expression. The first line in the output tells us what’s the name of the entity used to build this property in the context. Runtime information So let’s create a process to see what happens. We can bind a source to a sink and run the resulting process. If you right click on the connection you can refresh it and see the process present in the list of entities. Then you can drag the process to the query window and see that you can have access to process object in the Processes collection of the application. You can then manipulate the process (delete it, read its diagnostic view etc.). Regards, The StreamInsight Team

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  • Introduction to LinqPad Driver for StreamInsight 2.1

    - by Roman Schindlauer
    We are announcing the availability of the LinqPad driver for StreamInsight 2.1. The purpose of this blog post is to offer a quick introduction into the new features that we added to the StreamInsight LinqPad driver. We’ll show you how to connect to a remote server, how to inspect the entities present of that server, how to compose on top of them and how to manage their lifetime. Installing the driver Info on how to install the driver can be found in an earlier blog post here. Establishing connections As you click on the “Add Connection” link in the left pane you will notice that now it’s possible to build the data context automatically. The new driver appears as an option in the upper list, and if you pick it you will open a connection dialog that lets you connect to a remote StreamInsight server. The connection dialog lets you specify the address of the remote server. You will notice that it’s possible to pick up the binding information from the configuration file of the LinqPad application (which is normally in the same folder as LinqPad.exe and is called LinqPad.exe.config). In order for the context to be generated you need to pick an application from the server. The control is editable hence you can create a new application if you don’t want to make changes to an existing application. If you choose a new application name you will be prompted for confirmation before this gets created. Once you click OK the connection is created and you can start issuing queries against the remote server. If there’s any connectivity error the connection is marked with a red X and you can see the error message informing you what went wrong (i.e., the remote server could not be reached etc.). The context for remote servers Let’s take a look at what happens after we are connected successfully. Every LinqPad query runs inside a context – think of it as a class that wraps all the code that you’re writing. If you’re connecting to a live server the context will contain the following: The application object itself. All entities present in this application (sources, sinks, subjects and processes). The picture below shows a snapshot of the left pane of LinqPad after a successful connection. Every entity on the server has a different icon which will allow users to figure out its purpose. You will also notice that some entities have a string in parentheses following the name. It should be interpreted as such: the first name is the name of the property of the context class and the second name is the name of the entity as it exists on the server. Not all valid entity names are valid identifier names so in cases where we had to make a transformation you see both. Note also that as you hover over the entities you get IntelliSense with their types – more on that later. Remoting is not supported As you play with the entities exposed by the context you will notice that you can’t read and write directly to/from them. If for instance you’re trying to dump the content of an entity you will get an error message telling you that in the current version remoting is not supported. This is because the entity lives on the remote server and dumping its content means reading the events produced by this entity into the local process. ObservableSource.Dump(); Will yield the following error: Reading from a remote 'System.Reactive.Linq.IQbservable`1[System.Int32]' is not supported. Use the 'Microsoft.ComplexEventProcessing.Linq.RemoteProvider.Bind' method to read from the source using a remote observer. This basically tells you that you can call the Bind() method to direct the output of this source to a sink that has to be defined on the remote machine as well. You can’t bring the results to the LinqPad window unless you write code specifically for that. Compose queries You may ask – what's the purpose of all that? After all the same information is present in the EventFlowDebugger, why bother with showing it in LinqPad? First of all, What gets exposed in LinqPad is not what you see in the debugger. In LinqPad we have a property on the context class for every entity that lives on the server. Because LinqPad offers IntelliSense we in fact have much more information about the entity, and more importantly we can compose with that entity very easily. For example, let’s say that this code creates an entity: using (var server = Server.Connect(...)) {     var a = server.CreateApplication("WhiteFish");     var src = a         .DefineObservable<int>(() => Observable.Range(0, 3))         .Deploy("ObservableSource"); If later we want to compose with the source we have to fetch it and then we can bind something to     a.GetObservable<int>("ObservableSource)").Bind(... This means that we had to know a bunch of things about this: that it’s a source, that it’s an observable, it produces a result with payload Int32 and it’s named “ObservableSource”. Only the second and last bits of information are present in the debugger, by the way. As you type in the query window you see that all the entities are present, you get IntelliSense support for them and it’s much easier to make sense of what’s available. Let’s look at a scenario where composition is plausible. With the new programming model it’s possible to create “cold” sources that are parameterized. There was a way to accomplish that even in the previous version by passing parameters to the adapters, but this time it’s much more elegant because the expression declares what parameters are required. Say that we hover the mouse over the ThrottledSource source – we will see that its type is Func<int, int, IQbservable<int>> - this in effect means that we need to pass two int parameters before we can get a source that produces events, and the type for those events is int – in the particular case of my example I had the source produce a range of integers and the two parameters were the start and end of the range. So we see how a developer can create a source that is not running yet. Then someone else (e.g. an administrator) can pass whatever parameters appropriate and run the process. Proxy Types Here’s an interesting scenario – what if someone created a source on a server but they forgot to tell you what type they used. Worse yet, they might have used an anonymous type and even though they can refer to it by name you can’t figure out how to use that type. Let’s walk through an example that shows how you can compose against types you don’t need to have the definition of. This is how we can create a source that returns an anonymous type: Application.DefineObservable(() => Observable.Range(1, 10).Select(i => new { I = i })).Deploy("O1"); Now if we refresh the connection we can see the new source named O1 appear in the list. But what’s more important is that we now have a type to work with. So we can compose a query that refers to the anonymous type. var threshold = new StreamInsightDynamicDriver.TypeProxies.AnonymousType1_0<int>(5); var filter = from i in O1              where i > threshold              select i; filter.Deploy("O2"); You will notice that the anonymous type defined with this statement: new { I = i } can now be manipulated by a client that does not have access to it because the LinqPad driver has generated another type in its stead, named StreamInsightDynamicDriver.TypeProxies.AnonymousType1_0. This type has all the properties and fields of the type defined on the server, except in this case we can instantiate values and use it to compose more queries. It is worth noting that the same thing works for types that are not anonymous – the test is if the LinqPad driver can resolve the type or not. If it’s not possible then a new type will be generated that approximates the type that exists on the server. Control metadata In addition to composing processes on top of the existing entities we can do other useful things. We can delete them – nothing new here as we simply access the entities through the Entities collection of the application class. Here is where having their real name in parentheses comes handy. There’s another way to find out what’s behind a property – dump its expression. The first line in the output tells us what’s the name of the entity used to build this property in the context. Runtime information So let’s create a process to see what happens. We can bind a source to a sink and run the resulting process. If you right click on the connection you can refresh it and see the process present in the list of entities. Then you can drag the process to the query window and see that you can have access to process object in the Processes collection of the application. You can then manipulate the process (delete it, read its diagnostic view etc.). Regards, The StreamInsight Team

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  • Unable to create installdriver instance

    - by Entity
    When trying to install a program called "AV Grabber", I get the following error message. unable to create installdriver instance Product name is: EZ Grabber Right click on the executable 7.1.79.0 I have tried installing Install Sheild 7, but have no luck trying to remove this error message. Any Ideas? Machine: Windows XP (Home Edition) User Account: Administrator Account Folder version of installshield is visible from: C:\Program Files\Common Files\InstallShield\Driver\7\Intel 32 Have tried the following command, but have not helped. "C:\Program Files\Common Files\InstallShield\Driver\7\Intel 32\IDriver.exe" -Embedding

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  • Explicit construction of entity type [MyClass] in query is not allowed.

    - by Code Sherpa
    Hi. Like the title says, I have the following exception: Description: Event code: 3005 Event message: An unhandled exception has occurred. Exception information: Exception type: NotSupportedException Exception message: Explicit construction of entity type 'Company.Project.Core.Domain.Friend' in query is not allowed. I am using LINQ and have the following code in my datacontext: var friends2 = (dc.Friends .Where(f => f.MyFriendsAccountId == accountId && f.AccountId != accountId) .Select(f => new { f.FriendId, AccountId = f.MyFriendsAccountId, MyFriendsAccountId = f.AccountId, f.CreateDate, f.Timestamp })).Distinct(); result.AddRange(friends2 .Select(o => new Friend { FriendId = o.FriendId, AccountId = o.AccountId, CreateDate = o.CreateDate, MyFriendsAccountId = o.MyFriendsAccountId, Timestamp = o.Timestamp })); the final code block is throwing the error and I am pretty sure it is this statement that is the culprit: .Select( o => **new Friend** How should I be reworking my code to avoid this error? Code illustration appreciated. Thanks.

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