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• Is there an API for listing queues and exchanges on RabbitMQ?

  - by parsenome

  I've looked quite a bit, but I haven't been able to find a good programmatic way to list the queues on a RabbitMQ server. This is important because I need to clean up my queues and exchanges when I'm done with them. I don't always have a good "done" event that can be used to trigger a cleanup, so I'd like to do it with more of a garbage collection model. If I can list the queues, I can verify that the objects that they're related to shouldn't be producing more entries and clean them up. I know I can use rabbitmqctl to do it, but that needs elevated privileges. Since I haven't been able to find a way to list the queues programmatically, I've been keeping a list of names in the database. That works, but it's ugly.

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• Can you explain this odd behavior with dragging items into nested sortables?

  - by RDL

  I have the following setup: A sortable list where one of the <li> has a table with lists in each cell. All of the lists are sortable with each other. Draggable items that can be added to any of the sortables Issue: When adding a draggable item ('drag 1', 'drag 2', 'drag 3') to one of the lists in the horizontal lists (table of lists) it duplicates the draggable when dropped. Sometimes it will create both copies in the same list or one in the item list and one in the column list. Here is a demo: http://jsfiddle.net/MQTgA/ Question: How do I prevent the second item being created when dropping the draggable?

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• Is HTTP 404 appropriate for out of range page number on paged content?

  - by WooYek

  I have a site that is mainly showing a paged list of content (articles, data element's, etc.), and I'm wondering about returning HTTP 404 when user navigates outside of the available list range. Some sites just display "No results/Page number out of range" and some return additionally return HTTP 404 status. What's your take on that, and why? UPDATE It's not and api response. This question is in regard to user viewed pages that among other things show a list/table in the main area.

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• LINQ to Entity: using Contains in the "select" portion throws unexpected error

  - by Chu

  I've got a LINQ query going against an Entity Framework object. Here's a summary of the query: //a list of my allies List<int> allianceMembers = new List<int>() { 1,5,10 }; //query for fleets in my area, including any allies (and mark them as such) var fleets = from af in FleetSource select new Fleet { fleetID = af.fleetID, fleetName = af.fleetName, isAllied = (allianceMembers.Contains(af.userID) ? true : false) }; Basically, what I'm doing is getting a set of fleets. The allianceMembers list contains INTs of all users who are allied with me. I want to set isAllied = true if the fleet's owner is part of that list, and false otherwise. When I do this, I am seeing an exception: "LINQ to Entities does not recognize the method 'Boolean Contains(Int32)' method" I can understand getting this error if I had used the contains in the where portion of the query, but why would I get it in the select? By this point I would assume the query would have executed and returned the results. This little ditty of code does nothing to constrain my data at all. Any tips on how else I can accomplish what I need to with setting the isAllied flag? Thanks

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• c# event fires windows form incorrectly

  - by MikeW

  I'm trying to understand what's happening here. I have a CheckedListBox which contains some ticked and some un-ticked items. I'm trying to find a way of determining the delta in the selection of controls. I've tried some cumbersome like this - but only works part of the time, I'm sure there's a more elegant solution. A maybe related problem is the myCheckBox_ItemCheck event fires on form load - before I have a chance to perform an ItemCheck. Here's what I have so far: void clbProgs_ItemCheck(object sender, ItemCheckEventArgs e) { // i know its awful System.Windows.Forms.CheckedListBox cb = (System.Windows.Forms.CheckedListBox)sender; string sCurrent = e.CurrentValue.ToString(); int sIndex = e.Index; AbstractLink lk = (AbstractLink)cb.Items[sIndex]; List<ILink> _links = clbProgs.DataSource as List<ILink>; foreach (AbstractLink lkCurrent in _links) { if (!lkCurrent.IsActive) { if (!_groupValues.ContainsKey(lkCurrent.Linkid)) { _groupValues.Add(lkCurrent.Linkid, lkCurrent); } } } if (_groupValues.ContainsKey(lk.Linkid)) { AbstractLink lkDirty = (AbstractLink)lk.Clone(); CheckState newValue = (CheckState)e.NewValue; if (newValue == CheckState.Checked) { lkDirty.IsActive = true; } else if (newValue == CheckState.Unchecked) { lkDirty.IsActive = false; } if (_dirtyGroups.ContainsKey(lk.Linkid)) { _dirtyGroups[lk.Linkid] = lkDirty; } else { CheckState oldValue = (CheckState)e.NewValue; if (oldValue == CheckState.Checked) { lkDirty.IsActive = true; } else if (oldValue == CheckState.Unchecked) { lkDirty.IsActive = false; } _dirtyGroups.Add(lk.Linkid, lk); } } else { if (!lk.IsActive) { _dirtyGroups.Add(lk.Linkid, lk); } else { _groupValues.Add(lk.Linkid, lk); } } } Then onclick of a save button - I check whats changed before sending to database: private void btSave_Click(object sender, EventArgs e) { List<AbstractLink> originalList = new List<AbstractLink>(_groupValues.Values); List<AbstractLink> changedList = new List<AbstractLink>(_dirtyGroups.Values); IEnumerable<AbstractLink> dupes = originalList.ToArray<AbstractLink>().Intersect(changedList.ToArray<AbstractLink>()); foreach (ILink t in dupes) { MessageBox.Show("Changed"); } if (dupes.Count() == 0) { MessageBox.Show("No Change"); } } For further info. The definition of type AbstractLink uses: public bool Equals(ILink other) { if (Object.ReferenceEquals(other, null)) return false; if (Object.ReferenceEquals(this, other)) return true; return IsActive.Equals(other.IsActive) && Linkid.Equals(other.Linkid); }

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• designing an ASP.NET MVC partial view - showing user choices within a large set of choices

  - by p.campbell

  Consider a partial view whose job is to render markup for a pizza order. The desire is to reuse this partial view in the Create, Details, and Update views. It will always be passed an IEnumerable<Topping>, and output a multitude of checkboxes. There are lots... maybe 40 in all (yes, that might smell). A-OK so far. Problem The question is around how to include the user's choices on the Details and Update views. From the datastore, we've got a List<ChosenTopping>. The goal is to have each checkbox set to true for each chosen topping. What's the easiest to read, or most maintainable way to achieve this? Potential Solutions Create a ViewModel with the List and List. Write out the checkboxes as per normal. While writing each, check whether the ToppingID exists in the list of ChosenTopping. Create a new ViewModel that's a hybrid of both. Perhaps call it DisplayTopping or similar. It would have property ID, Name and IsUserChosen. The respective controller methods for Create, Update, and Details would have to create this new collection with respect to the user's choices as they see fit. The Create controller method would basically set all to false so that it appears to be a blank slate. The real application isn't pizza, and the organization is a bit different from the fakeshot, but the concept is the same. Is it wise to reuse the control for the 3 different scenarios? How better can you display the list of options + the user's current choices? Would you use jQuery instead to show the user selections? Any other thoughts on the potential smell of splashing up a whole bunch of checkboxes?

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• How to do client callback for each item in a foreach statement using c#?

  - by Mike108

  I want to show each item Id that is doing now dynamically in a foreach statement. How to do some kind of client callback to show the item Id in a foreach statement? <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label> <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" /> . protected void Button1_Click(object sender, EventArgs e) { List<int> list = new List<int>() { 1,2,3,4,5 }; foreach (var item in list) { Label1.Text = string.Format("I'm doing item {0} now.", item.ToString()); Page.RegisterStartupScript("", string.Format("<script>alert('doing item {0} now')</script>", item.ToString())); Thread.Sleep(1 * 1000); } }

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• is using private shared objects/variables on class level harmful ?

  - by haansi

  Hello, Thanks for your attention and time. I need your opinion on an basic architectural issue please. In page behind classes I am using a private and shared object and variables (list or just client or simplay int id) to temporary hold data coming from database or class library. This object is used temporarily to catch data and than to return, pass to some function or binding a control. 1st: Can this approach harm any way ? I couldn't analyze it but a thought was using such shared variables may replace data in it when multiple users may be sending request at a time? 2nd: Please comment also on using such variables in BLL (to hold data coming from DAL/database). In this example every time new object of BLL class will be made. Here is sample code: public class ClientManager { Client objclient = new Client(); //Used in 1st and 2nd method List<Client> clientlist = new List<Client>();// used in 3rd and 4th method ClientRepository objclientRep = new ClientRepository(); public List<Client> GetClients() { return clientlist = objclientRep.GetClients(); } public List<Client> SearchClients(string Keyword) { return clientlist = objclientRep.SearchClients(Keyword); } public Client GetaClient(int ClientId) { return objclient = objclientRep.GetaClient(ClientId); } public Client GetClientDetailForConfirmOrder(int UserId) { return objclientRep.GetClientDetailForConfirmOrder(UserId); } } I am really thankful to you for sparing time and paying kind attention.

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• Dealing with array of IntPtr

  - by Padu Merloti

  I think I'm close and I bet the solution is something stupid. I have a C++ native DLL where I define the following function: DllExport bool __stdcall Open(const char* filePath, int *numFrames, void** data); { //creates the list of arrays here... don't worry, lifetime is managed somewhere else //foreach item of the list: { BYTE* pByte = GetArray(i); //here's where my problem lives *(data + i * sizeofarray) = pByte; } *numFrames = total number of items in the list return true; } Basically, given a file path, this function creates a list of byte arrays (BYTE*) and should return a list of pointers via the data param. Each pointing to a different byte array. I want to pass an array of IntPtr from C# and be able to marshal each individual array in order. Here's the code I'm using: [DllImport("mydll.dll",EntryPoint = "Open")] private static extern bool MyOpen( string filePath, out int numFrames, out IntPtr[] ptr); internal static bool Open( string filePath, out int numFrames, out Bitmap[] images) { var ptrList = new IntPtr[512]; MyOpen(filePath, out numFrames, out ptrList); images = new Bitmap[numFrames]; var len = 100; //for sake of simplicity for (int i=0; i<numFrames;i++) { var buffer = new byte[len]; Marshal.Copy(ptrList[i], buffer, 0, len); images[i] = CreateBitmapFromBuffer(buffer, height, width); } return true; } Problem is in my C++ code. When I assign *(data + i * sizeofarray) = pByte; it corrupts the array of pointers... what am I doing wrong?

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• Javascript Prototype Best Practice Event Handlers

  - by nahum

  Hi this question is more a consulting of best practice, Sometimes when I'm building a complete ajax application I usually add elements dynamically for example. When you'r adding a list of items, I do something like: var template = new Template("<li id='list#{id}'>#{value}</li>"); var arrayTemplate = []; arrayOfItem.each(function(item, index){ arrayTemplate.push(template.evaluate( id : index, value : item)) }); after this two options add the list via "update" or "insert" ----- $("elementToUpdate").update("<ul>" + arrayTemplate.join("") + "</ul">); the question is how can I add the event handler without repeat the process of read the array, this is because if you try add a Event before the update or insert you will get an Error because the element isn't still on the DOM. so what I'm doing by now is after insert or update: arrayOfItem.each(function(item, index){ $("list" + index).observe("click", function(){ alert("I see the world"); }) }); so the question is exist a better way to doing this??????

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• How to build unlimited level of menu through PHP and mysql

  - by Starx

  Well, to build my menu my menu I use a db similar structure like this To assign another submenu for existing submenu I simply assign its parent's id as its value of parent field. parent 0 means top menu now there is not problem while creating submenu inside another submenu now this is way I fetch the submenu for the top menu <ul class="topmenu"> <? $list = $obj -> childmenu($parentid); //this list contains the array of submenu under $parendid foreach($list as $menu) { extract($menu); echo '<li><a href="#">'.$name.'</a></li>'; } ?> </ul> What I want to do is. I want to check if a new menu has other child menu and I want to keep on checking until it searches every child menu that is available and I want to display its child menu inside its particular list item like this Home ........

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• is there a better way to write this frankenstein LINQ query that searches for values in a child tabl

  - by MRV

  I have a table of Users and a one to many UserSkills table. I need to be able to search for users based on skills. This query takes a list of desired skills and searches for users who have those skills. I want to sort the users based on the number of desired skills they posses. So if a users only has 1 of 3 desired skills he will be further down the list than the user who has 3 of 3 desired skills. I start with my comma separated list of skill IDs that are being searched for: List<short> searchedSkillsRaw = skills.Value.Split(',').Select(i => short.Parse(i)).ToList(); I then filter out only the types of users that are searchable: List<User> users = (from u in db.Users where u.Verified == true && u.Level > 0 && u.Type == 1 && (u.UserDetail.City == city.SelectedValue || u.UserDetail.City == null) select u).ToList(); and then comes the crazy part: var fUsers = from u in users select new { u.Id, u.FirstName, u.LastName, u.UserName, UserPhone = u.UserDetail.Phone, UserSkills = (from uskills in u.UserSkills join skillsJoin in configSkills on uskills.SkillId equals skillsJoin.ValueIdInt into tempSkills from skillsJoin in tempSkills.DefaultIfEmpty() where uskills.UserId == u.Id select new { SkillId = uskills.SkillId, SkillName = skillsJoin.Name, SkillNameFound = searchedSkillsRaw.Contains(uskills.SkillId) }), UserSkillsFound = (from uskills in u.UserSkills where uskills.UserId == u.Id && searchedSkillsRaw.Contains(uskills.SkillId) select uskills.UserId).Count() } into userResults where userResults.UserSkillsFound > 0 orderby userResults.UserSkillsFound descending select userResults; and this works! But it seems super bloated and inefficient to me. Especially the secondary part that counts the number of skills found. Thanks for any advice you can give. --r

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• For loop index out of range ArgumentOutOfRangeException when multithreading

  - by Lirik

  I'm getting some strange behavior... when I iterate over the dummyText List in the ThreadTest method I get an index out of range exception (ArgumentOutOfRangeException), but if I remove the threads and I just print out the text, then everything works fine. This is my main method: public static Object sync = new Object(); static void Main(string[] args) { ThreadTest(); Console.WriteLine("Press any key to continue."); Console.ReadKey(); } This method throws the exception: private static void ThreadTest() { Console.WriteLine("Running ThreadTest"); Console.WriteLine("Running ThreadTest"); List<String> dummyText = new List<string>() { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"}; for (int i = 0; i < dummyText.Count; i++) { Thread t = new Thread(() => PrintThreadName(dummyText[i])); // <-- Index out of range?!? t.Name = ("Thread " + (i)); t.IsBackground = true; t.Start(); } } private static void PrintThreadName(String text) { Random rand = new Random(DateTime.Now.Millisecond); while (true) { lock (sync) { Console.WriteLine(Thread.CurrentThread.Name + " running " + text); Thread.Sleep(1000+rand.Next(0,2000)); } } } This does not throw the exception: private static void ThreadTest() { Console.WriteLine("Running ThreadTest"); List<String> dummyText = new List<string>() { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten"}; for (int i = 0; i < dummyText.Count; i++) { Console.WriteLine(dummyText[i]); // <-- No exception here } } Does anybody know why this is happening?

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• Lookup Field as a Site Column via CAML

  - by Rob Windsor

  I'm trying to create a Lookup Field as a Site Column via CAML. The list I want to use as the source of the lookup is created in the Feature Receiver so I don't know it's ID. I've read several blog posts that indicate that I can just put the path to the list in the List attribute. It seems from the comments on these post that this solution works for some people but not for others. I'm in the latter group. When I try to associate a content type that uses the lookup site column I: "Exception from HRESULT: 0x80040E07" <Field ID="{da94e56b-428f-4b95-b4c6-24aed0256475}" Name="Test_x0020_Lookup_x0020_Column" StaticName="Test_x0020_Lookup_x0020_Column" DisplayName="Test Lookup Column" Type="Lookup" Required="FALSE" List="Lists/Test" ShowField="Title" PrependId="TRUE" Group="Test Site Columns" /> <ContentType ID="0x0100B6D92594DDCE8E479D0EB0C414C463B0" Name="Test Lookup Content Type" Version="0" Group="Test Content Types"> <FieldRefs> <FieldRef ID="{da94e56b-428f-4b95-b4c6-24aed0256475}" Name="Test_x0020_Lookup_x0020_Column" Required="TRUE" /> </FieldRefs> </ContentType>

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• Access the internal phonebook

  - by L0rdAli3n

  For more than two days now, I'm trying to grab a list of all contacts, from the internal phonebook (no facebook-, gmail- or twittercontacts) with their family- and givenname. I managed to get a list with all contacts, socialcontacts included. So I looked at the account_type and saw that on my HTC Desire they were all "com.htc.android.pcsc" and I was like "Great, I just have to filter the whole list". But then all people with non-htc android cellphones would be unable to use my app, if I would hardcode this filter. Next idea was to let the user choose which account he wants to use, but unfortunately the "com.htc.android.pcsc" didn't appear in the list I got from the AccountManager?!? So my question is: Is there any standardized way to access the internal phonebook? I'm really stuck with that and any hint is highly appreciated!

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• What human learning techniques can be applied to improve code layout?

  - by David Sykes

  Is it possible to use the results of studies made into human learning in order to identify how code might be laid out to improve comprehension? Code layout wars almost always end up defending consistency and the prevailing style, but could there be ways of laying out code that are provably better than others?

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• JPA/Hibernate Parent/Child relationship

  - by NubieJ

  Hi I am quite new to JPA/Hibernate (Java in general) so my question is as follows (note, I have searched far and wide and have not come across an answer to this): I have two entities: Parent and Child (naming changed). Parent contains a list of Children and Children refers back to parent. e.g. @Entity public class Parent { @Id @Basic @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "PARENT_ID", insertable = false, updatable = false) private int id; /* ..... */ @OneToMany(cascade = { CascadeType.ALL }, fetch = FetchType.LAZY) @JoinColumn(name = "PARENT_ID", referencedColumnName = "PARENT_ID", nullable = true) private Set<child> children; /* ..... */ } @Entity public class Child { @Id @Basic @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "CHILD_ID", insertable = false, updatable = false) private int id; /* ..... */ @ManyToOne(cascade = { CascadeType.REFRESH }, fetch = FetchType.EAGER, optional = false) @JoinColumn(name = "PARENT_ID", referencedColumnName = "PARENT_ID") private Parent parent; /* ..... */ } I want to be able to do the following: Retrieve a Parent entity which would contain a list of all its children (List), however, when listing Parent (getting List, it of course should omit the children from the results, therefore setting FetchType.LAZY. Retrieve a Child entity which would contain an instance of the Parent entity. Using the code above (or similar) results in two exceptions: Retrieving Parent: A cycle is detected in the object graph. This will cause infinitely deep XML... Retrieving Child: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: xxxxxxxxxxx, no session or session was closed When retrieving the Parent entity, I am using a named query (i.e. calling it specifically) @NamedQuery(name = "Parent.findByParentId", query = "SELECT p FROM Parent AS p LEFT JOIN FETCH p.children where p.id = :id") Code to get Parent (i.e. service layer): public Parent findByParentId(int parentId) { Query query = em.createNamedQuery("Parent.findByParentId"); query.setParameter("id", parentId); return (Parent) query.getSingleResult(); } Why am I getting a LazyInitializationException event though the List property on the Parent entity is set as Lazy (when retrieving the Child entity)?

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• Best way to return result from business layer to presentation layer when using LINQ-to-SQL

  - by samsur

  I have a business layer that has DTOs that are used in the presentation layer. This application uses entity framework. Here is an example of a class called RoleDTO: public class RoleDTO { public Guid RoleId { get; set; } public string RoleName { get; set; } public string RoleDescription { get; set; } public int? OrganizationId { get; set; } } In the BLL I want to have a method that returns a list of DTO. I would like to know which is the better approach: returning IQueryable or list of DTOs. Although I feel that returning IQueryable is not a good idea because the connection needs to be open. Here are the 2 different methods using the different approaches: First approach public class RoleBLL { private servicedeskEntities sde; public RoleBLL() { sde = new servicedeskEntities(); } public IQueryable<RoleDTO> GetAllRoles() { IQueryable<RoleDTO> role = from r in sde.Roles select new RoleDTO() { RoleId = r.RoleID, RoleName = r.RoleName, RoleDescription = r.RoleDescription, OrganizationId = r.OrganizationId }; return role; } Note: in the above method the DataContext is a private attribute and set in the constructor, so that the connection stays opened. Second approach public static List<RoleDTO> GetAllRoles() { List<RoleDTO> roleDTO = new List<RoleDTO>(); using (servicedeskEntities sde = new servicedeskEntities()) { var roles = from pri in sde.Roles select new { pri.RoleID, pri.RoleName, pri.RoleDescription }; //Add the role entites to the DTO list and return. This is necessary as anonymous types can be returned acrosss methods foreach (var item in roles) { RoleDTO roleItem = new RoleDTO(); roleItem.RoleId = item.RoleID; roleItem.RoleDescription = item.RoleDescription; roleItem.RoleName = item.RoleName; roleDTO.Add(roleItem); } return roleDTO; } } Please let me know, if there is a better approach.

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• Refresh a ListView if I change the content of the ListItem

  - by michael

  Hi, I have a ListView in my android activity. And I populate the ListView by sub-class the BaseAdaptor (which returns a View in getView() method). What if in my click listener of a button in a list item view, I change the text of the TextView in the List item view or change the dimension of the list item view by adding/removing children of the list item view What is an efficient to refresh my listView? I don't want the listView to re-trigger a query since there is no data change. Thank you.

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• Returning pointers in a thread-safe way.

  - by Roddy

  Assume I have a thread-safe collection of Things (call it a ThingList), and I want to add the following function. Thing * ThingList::findByName(string name) { return &item[name]; // or something similar.. } But by doing this, I've delegated the responsibility for thread safety to the calling code, which would have to do something like this: try { list.lock(); // NEEDED FOR THREAD SAFETY Thing *foo = list.findByName("wibble"); foo->Bar = 123; list.unlock(); } catch (...) { list.unlock(); throw; } Obviously a RAII lock/unlock object would simplify/remove the try/catch/unlocks, but it's still easy for the caller to forget. There are a few alternatives I've looked at: Return Thing by value, instead of a pointer - fine unless you need to modify the Thing Add function ThingList::setItemBar(string name, int value) - fine, but these tend to proliferate Return a pointerlike object which locks the list on creation and unlocks it again on destruction. Not sure if this is good/bad practice... What's the right approach to dealing with this?

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• ASP.NET MVC - How to Unit Test boundaries in the Repository pattern?

  - by JK

  Given a basic repository interface: public interface IPersonRepository { void AddPerson(Person person); List<Person> GetAllPeople(); } With a basic implementation: public class PersonRepository: IPersonRepository { public void AddPerson(Person person) { ObjectContext.AddObject(person); } public List<Person> GetAllPeople() { return ObjectSet.AsQueryable().ToList(); } } How can you unit test this in a meaningful way? Since it crosses the boundary and physically updates and reads from the database, thats not a unit test, its an integration test. Or is it wrong to want to unit test this in the first place? Should I only have integration tests on the repository? I've been googling the subject and blogs often say to make a stub that implements the IRepository: public class PersonRepositoryTestStub: IPersonRepository { private List<Person> people = new List<Person>(); public void AddPerson(Person person) { people.Add(person); } public List<Person> GetAllPeople() { return people; } } But that doesnt unit test PersonRepository, it tests the implementation of PersonRepositoryTestStub (not very helpful).

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• Memory management of objects returned by methods (iOS / Objective-C)

  - by iOSNewb

  I am learning Objective-C and iOS programming through the terrific iTunesU course posted by Stanford (http://www.stanford.edu/class/cs193p/cgi-bin/drupal/) Assignment 2 is to create a calculator with variable buttons. The chain of commands (e.g. 3+x-y) is stored in a NSMutableArray as "anExpression", and then we sub in random values for x and y based on an NSDictionary to get a solution. This part of the assignment is tripping me up: The final two [methods] “convert” anExpression to/from a property list: + (id)propertyListForExpression:(id)anExpression; + (id)expressionForPropertyList:(id)propertyList; You’ll remember from lecture that a property list is just any combination of NSArray, NSDictionary, NSString, NSNumber, etc., so why do we even need this method since anExpression is already a property list? (Since the expressions we build are NSMutableArrays that contain only NSString and NSNumber objects, they are, indeed, already property lists.) Well, because the caller of our API has no idea that anExpression is a property list. That’s an internal implementation detail we have chosen not to expose to callers. Even so, you may think, the implementation of these two methods is easy because anExpression is already a property list so we can just return the argument right back, right? Well, yes and no. The memory management on this one is a bit tricky. We’ll leave it up to you to figure out. Give it your best shot. Obviously, I am missing something with respect to memory management because I don't see why I can't just return the passed arguments right back. Thanks in advance for any answers!

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• Correct formulation of the A* algorithm

  - by Eli Bendersky

  Hello, I'm looking at definitions of the A* path-finding algorithm, and it seems to be defined somewhat differently in different places. The difference is in the action performed when going through the successors of a node, and finding that a successor is on the closed list. One approach (suggested by Wikipedia, and this article) says: if the successor is on the closed list, just ignore it Another approach (suggested here and here, for example) says: if the successor is on the closed list, examine its cost. If it's higher than the currently computed score, remove the item from the closed list for future examination. I'm confused - which method is correct ? Intuitively, the first makes more sense to me, but I wonder about the difference in definition. Is one of the definitions wrong, or are they somehow isomorphic ?

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• Appending an element to a collection using LINQ

  - by SRKX

  I am trying to process some list with a functional approach in C#. The idea is that I have a collection of Tuple<T,double> and I want to change the Item 2 of some element T. The functional way to do so, as data is immutable, is to take the list, filter for all elements where the element is different from the one to change, and the append a new tuple with the new values. My problem is that I do not know how to append the element at the end. I would like to do: public List<Tuple<T,double>> Replace(List<Tuple<T,double>> collection, T term,double value) { return collection.Where(x=>!x.Item1.Equals(term)).Append(Tuple.Create(term,value)); } But there is no Append method. Is there something else?

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• How to write simple code in LInq

  - by user281180

  I have the following in my NotSelectedList. public List<TestModel> SelectedList = new List<TestModel>(); public List<TestModel>NotSelectedList = new List<TestModel>(); NotificationDetailsModel projects = new NotificationDetailsModel(); projects.ProjectID = Convert.ToInt32(Row["ProjectID"]); projects.Valid= Convert.ToBoolean(Row["Validity"]); NotSelectedList.Add(projects); How can I write a simple code in LINQ to select from the NotSelectedList where Validity == True and store the data in SelectedList?

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