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  • Custom keys for Google App Engine models (Python)

    - by Cameron
    First off, I'm relatively new to Google App Engine, so I'm probably doing something silly. Say I've got a model Foo: class Foo(db.Model): name = db.StringProperty() I want to use name as a unique key for every Foo object. How is this done? When I want to get a specific Foo object, I currently query the datastore for all Foo objects with the target unique name, but queries are slow (plus it's a pain to ensure that name is unique when each new Foo is created). There's got to be a better way to do this! Thanks.

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  • Trying and expand the contrib.auth.user model and add a "relatipnships" manage

    - by dotty
    I have the following model setup. from django.db import models from django.contrib.auth.models import User class SomeManager(models.Manager): def friends(self): # return friends bla bla bla class Relationship(models.Model): """(Relationship description)""" from_user = models.ForeignKey(User, related_name='from_user') to_user = models.ForeignKey(User, related_name='to_user') has_requested_friendship = models.BooleanField(default=True) is_friend = models.BooleanField(default=False) objects = SomeManager() relationships = models.ManyToManyField(User, through=Relationship, symmetrical=False) relationships.contribute_to_class(User, 'relationships') Here i take the User object and use contribute_to_class to add 'relationships' to the User object. The relationship show up, but if call User.relationships.friends it should run the friends() method, but its failing. Any ideas how i would do this? Thanks

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  • Problems Enforcing Referential Integrity on SQL Server Tables

    - by SidC
    Hello All, I have a SQL Server 2005 database comprised of Customer, Quote, QuoteDetail tables. I want/need to enforce referential integrity such that when an insert is made on quotedetail, the quote and customer tables are also affected. I have tried my best to set up primary/foreign keys on my tables but need some help. Here's the scripts for my tables as they stand now (please don't laugh): Customers: USE [Diel_inventory] GO /****** Object: Table [dbo].[Customers] Script Date: 05/08/2010 03:39:04 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[Customers]( [pkCustID] [int] IDENTITY(1,1) NOT NULL, [CompanyName] [nvarchar](50) NULL, [Address] [nvarchar](50) NULL, [City] [nvarchar](50) NULL, [State] [nvarchar](2) NULL, [ZipCode] [nvarchar](5) NULL, [OfficePhone] [nvarchar](12) NULL, [OfficeFAX] [nvarchar](12) NULL, [Email] [nvarchar](50) NULL, [PrimaryContactName] [nvarchar](50) NULL, CONSTRAINT [PK_Customers] PRIMARY KEY CLUSTERED ([pkCustID] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] Quotes: USE [Diel_inventory] GO /****** Object: Table [dbo].[Quotes] Script Date: 05/08/2010 03:30:46 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[Quotes]( [pkQuoteID] [int] IDENTITY(1,1) NOT NULL, [fkCustomerID] [int] NOT NULL, [QuoteDate] [timestamp] NOT NULL, [NeedbyDate] [datetime] NULL, [QuoteAmt] [decimal](6, 2) NOT NULL, [QuoteApproved] [bit] NOT NULL, [fkOrderID] [int] NOT NULL, CONSTRAINT [PK_Bids] PRIMARY KEY CLUSTERED ( [pkQuoteID] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO ALTER TABLE [dbo].[Quotes] WITH CHECK ADD CONSTRAINT [fkCustomerID] FOREIGN KEY([fkCustomerID]) REFERENCES [dbo].[Customers] ([pkCustID]) GO ALTER TABLE [dbo].[Quotes] CHECK CONSTRAINT [fkCustomerID] QuoteDetail: USE [Diel_inventory] GO /****** Object: Table [dbo].[QuoteDetail] Script Date: 05/08/2010 03:31:58 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE TABLE [dbo].[QuoteDetail]( [ID] [int] IDENTITY(1,1) NOT NULL, [fkQuoteID] [int] NOT NULL, [fkCustomerID] [int] NOT NULL, [fkPartID] [int] NULL, [PartNumber1] [float] NOT NULL, [Qty1] [int] NOT NULL, [PartNumber2] [float] NULL, [Qty2] [int] NULL, [PartNumber3] [float] NULL, [Qty3] [int] NULL, [PartNumber4] [float] NULL, [Qty4] [int] NULL, [PartNumber5] [float] NULL, [Qty5] [int] NULL, [PartNumber6] [float] NULL, [Qty6] [int] NULL, [PartNumber7] [float] NULL, [Qty7] [int] NULL, [PartNumber8] [float] NULL, [Qty8] [int] NULL, [PartNumber9] [float] NULL, [Qty9] [int] NULL, [PartNumber10] [float] NULL, [Qty10] [int] NULL, [PartNumber11] [float] NULL, [Qty11] [int] NULL, [PartNumber12] [float] NULL, [Qty12] [int] NULL, [PartNumber13] [float] NULL, [Qty13] [int] NULL, [PartNumber14] [float] NULL, [Qty14] [int] NULL, [PartNumber15] [float] NULL, [Qty15] [int] NULL, [PartNumber16] [float] NULL, [Qty16] [int] NULL, [PartNumber17] [float] NULL, [Qty17] [int] NULL, [PartNumber18] [float] NULL, [Qty18] [int] NULL, [PartNumber19] [float] NULL, [Qty19] [int] NULL, [PartNumber20] [float] NULL, [Qty20] [int] NULL, CONSTRAINT [PK_QuoteDetail] PRIMARY KEY CLUSTERED ( [ID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] GO ALTER TABLE [dbo].[QuoteDetail] WITH CHECK ADD CONSTRAINT [FK_QuoteDetail_Customers] FOREIGN KEY ([fkCustomerID]) REFERENCES [dbo].[Customers] ([pkCustID]) GO ALTER TABLE [dbo].[QuoteDetail] CHECK CONSTRAINT [FK_QuoteDetail_Customers] GO ALTER TABLE [dbo].[QuoteDetail] WITH CHECK ADD CONSTRAINT [FK_QuoteDetail_PartList] FOREIGN KEY ([fkPartID]) REFERENCES [dbo].[PartList] ([RecID]) GO ALTER TABLE [dbo].[QuoteDetail] CHECK CONSTRAINT [FK_QuoteDetail_PartList] GO ALTER TABLE [dbo].[QuoteDetail] WITH CHECK ADD CONSTRAINT [FK_QuoteDetail_Quotes] FOREIGN KEY([fkQuoteID]) REFERENCES [dbo].[Quotes] ([pkQuoteID]) GO ALTER TABLE [dbo].[QuoteDetail] CHECK CONSTRAINT [FK_QuoteDetail_Quotes] Your advice/guidance on how to set these up so that customer ID in Customers is the same as in Quotes (referential integrity) and that CustomerID is inserted on Quotes and Customers when an insert is made to QuoteDetial would be much appreciated. Thanks, Sid

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  • Manipulating individual rows of a datagrid

    - by pfranchise
    Hey, recently I started working on a webpage that has a datagrid. I understand how to add datasources and that sort of thing, or at least I am starting to get it. But my question is about manipulating individual rows or cells. Is that only possible during the databind event handler, that is the only place I have been able to do it so far. I am sure there is a more abstract way of doing the things I want to do, but there are times where I just want to say Datagrid.add(row). I mean, if the datagrid is made up of a certain object type, can I make a new object of that type and just chuck it on the end? I am still new to this stuff, so perhaps what I want to do would defeat the purpose of this added abstraction, but figured I would ask around. Thanks for any advice, tips, or tricks people feel like sharing. Edit: for clarification I am using c#, entity framework, asp.net, and an SQL database.

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  • Find the right parameters for an event without using Design Mode in Visual Studio 2010

    - by Jason
    Is there a way to know what parameters are needed by an event in Visual Studio 2010? Let's say I have a DropDownList control and I want to bind a method to the "OnSelectedIndexChanged", I would do something like this In the ASPX File: <asp:DropDownList ID="lstMyList" runat="server" OnSelectedIndexChanged="lstMyList_SelectedIndexChanged"></asp:DropDownList> In the codebehind: protected void lstMyList_SelectedIndexChanged(object sender, EventArgs e) { ... } Is there a way to know what parameters the method needs? (In this case, an object for the sender and an EventArgs parameter for the event.) I know you can easily create the method by double-clicking the right event in Design Mode, but it does a mess with your code so I prefer not to use it. Thanks!

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  • Linq query challenge - can this be done?

    - 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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  • Dashcode Web App: How to programmatically manipulate bound array in dataSource?

    - by Kross
    Hi Everyone, I've started using Dashcode to write an interface for presenting the report data for some of our Cocoa tools. I am using a Dashcode data source and bindings to populate the elements in the WebView, and it all seems to be working well so far. One of the objects in my dataSource is an array of objects that I would like to manipulate programmatically. I can change the object values in the array just fine but if I want to replace the array, or any objects in the array, my bound table isn't able to observe the added objects. Here is the code that I thought would let me easily replace the bound array with new content: var dataSource = dashcode.getDataSource("reportData"); var newDetailArray = testArray(); dataSource.setValueForKeyPath(newDetailArray, "content.detailArray"); But this throws the exception: Exception while binding "content" to keypath "arrangedObjects " TypeError: Result of expression 'this.object.valueForKeyPath' [undefined] is not a function. Is there something I'm missing that will let me easily manipulate the array's contents programmatically?

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  • Pass Alot of Parameters on a Form to Action Struts2

    - by Neeraj
    I have been working on migrating a web application from Struts1 to Struts2. I have a simple Form with around 45 Fields (basically a grid with data). I have to capture all those in Struts2 Action.I noticed that in struts2 we have OGNL through which we just write getters setters in action itself by declaring fields locally to get those variables flowing in the request. I cannot write 45 getters/setters in my action, there must be a way to pass whole object(a POJO) from jsp to Action layer. In Struts 1, we normally get a ActionForm Object and/or get request parameters in a map and then populate. Any help or suggestions will be appreciated.

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  • ASP.NET Forms automation/serialization/binding

    - by creo
    I need to implement many forms in ASP.NET application (for IRS mostly). There are will be a lot of standard controls for each form (textboxes, dropdowns, checkboxes, radio). And business entity assigned to each. What's the best solution to automate this process? I need to: Have layout stored in DB (in XML). Layout must support several columns, tabbed interface Automatically bind business object values to the form Automatically read form values and write to business object Must support automatic validation Some basic workflows support would be good I used to work with TFS and saw how they implemented WorkItem templates (.wit files). In general this is all I need. But what framework did they build it on? How can I utilize this solution? I know about Dynamic Data only: http://www.asp.net/dynamicdata

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  • Django or Drupal, which one should I use that suits best my needs ?

    - by HJ-INCPP
    Hello, I want to learn and use Drupal or Django for the following: dynamic web sites, medium database, multi-level users, paypal integration, content managment, speed (developing), security I like MVC, ORM and object-oriented prg. Which is better to jump into ? Which one is more mature, powerful, understandable, object-oriented and easier to use by the time ? What about Python Spring ... Also, which of these 3 are better documented, are better for a cv and have more extensions? Known languages: php, java, mysql Thank you !

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  • Javascript: Passing large objects or strings between function considered a bad practice

    - by Mr. Smee
    Is it considered a bad practice to pass around a large string or object (lets say from an ajax response) between functions? Would it be beneficial in any way save the response in a variable and keep reusing that variable? So in the code it would be something like this: var response; $.post(url, function(resp){ response = resp; }) function doSomething() { // do something with the response here } vs $.post(url, function(resp){ doSomething(resp); }) function doSomething(resp) { // do something with the resp here } Assume resp is a large object or string and it can be passed around between multiple functions.

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  • Tying PyQt4 QAction triggered() to local class callable doesn't seem to work. How to debug this?

    - by Jon Watte
    I create this object when I want to create a QAction. I then add this QAction to a menu: class ActionObject(object): def __init__(self, owner, command): action = QtGui.QAction(command.name, owner) self.action = action self.command = command action.setShortcut(command.shortcut) action.setStatusTip(command.name) QtCore.QObject.connect(action, QtCore.SIGNAL('triggered()'), self.triggered) def triggered(self): print("got triggered " + self.command.id + " " + repr(checked)) Unfortunately, when the menu item is selected, the 'triggered' function is not called. QtCore.QObject.connect() returns True. Nothing is printed on the console to indicate that anything is wrong, and no exception is thrown. How can I debug this? (or, what am I doing wrong?)

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  • How do I call the methods in a model via controller? Zend Framework

    - by Joel
    Hi guys, I've been searching for tutorials to better understand this, but I'm having no luck. Please forgive the lengthy explination, but I want make sure I explain myself well. First, I'm quite new to the MVC structure, though I have been doing tutorials and learning as best I can. I have been moving over a live site into the Zend Framework model. So far, I have all the views within views/scripts/index/example.phtml. So therefore I'm using one IndexController and I have the code in each Action method for each page: IE public function exampleAction() Because I didn't know how to interact with a model, I put all the methods at the bottom of the controller (a fat controller). So basically, I had a working site by using a View and Controller and no model. ... Now I'm trying to learn how to incorporate the Model. So I created a View at: view/scripts/calendar/index.phtml I created a new Controller at: controller/CalendarControllers.php and a new model at: model/Calendar.php The problem is I think I'm not correctly communication with the model (I'm still new to OOP). Can you look over my controller and model and tell me if you see a problem. I'm needing to return an array from runCalendarScript(), but I'm not sure if I can return an array into the object like I'm trying to? I don't really understand how to "run" the runCalendarScript() from the controller? Thanks for any help! I'm stripping out most of the guts of the methods for the sake of brevity: controller: <?php class CalendarController extends Zend_Controller_Action { public function indexAction() { $finishedFeedArray = new Application_Model_Calendar(); $this->view->googleArray = $finishedFeedArray; } } model: <?php class Application_Model_Calendar { public function _runCalendarScript(){ $gcal = $this->_validateCalendarConnection(); $uncleanedFeedArray = $this->_getCalendarFeed($gcal); $finishedFeedArray = $this->_cleanFeed($uncleanedFeedArray); return $finishedFeedArray; } //Validate Google Calendar connection public function _validateCalendarConnection() { ... return $gcal; } //extracts googles calendar object into the $feed object public function _getCalendarFeed($gcal) { ... return $feed; } //cleans the feed to just text, etc protected function _cleanFeed($uncleanedFeedArray) { $contentText = $this->_cleanupText($event); $eventData = $this->_filterEventDetails($contentText); return $cleanedArray; } //Cleans up all formatting of text from Calendar feed public function _cleanupText($event) { ... return $contentText; } //filterEventDetails protected function _filterEventDetails($contentText) { ... return $data; } }

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  • patching java reflect calls using AOP

    - by Oleg Pavliv
    I don't have a lot of experience with Jboss AOP and I'm just curious if it's possible to replace all calls like Field f = foo.class.getDeclaredField("bar"); f.set(object, value); with something like Field f = foo.class.getDeclaredField("bar"); FieldSetCaller.invoke(f, object, value); using Jboss AOP. FieldSetCaller is my own class. I need to replace all Field.set calls on the fly, without recompiling the code. Some third -party code I even cannot recompile because I don't have the source. I can achieve this using java asm framework and I'm wandering if Jboss AOP can do it as well. Just for information - my code is running on Jboss server 4.3.0

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  • mystified by qr.Q(): what is an orthonormal matrix in "compact" form?

    - by gappy
    R has a qr() function, which performs QR decomposition using either LINPACK or LAPACK (in my experience, the latter is 5% faster). The main object returned is a matrix "qr" that contains in the upper triangular matrix R (i.e. R=qr[upper.tri(qr)]). So far so good. The lower triangular part of qr contains Q "in compact form". One can extract Q from the qr decomposition by using qr.Q(). I would like to find the inverse of qr.Q(). In other word, I do have Q and R, and would like to put them in a "qr" object. R is trivial but Q is not. The goal is to apply to it qr.solve(), which is much faster than solve() on large systems.

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  • hibernate search

    - by Odelya
    Hi! I am using Hibernate. I am looking for a free text engine. Before I investigate into it I need your experience. I have in my applications user, role and object table. Where a user is connected to one or more roles, and a role is connected to one or more objects. In my free text search, the user can reach only data that he is allowed to watch by object table. Can Hibernate search help me with it?

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  • MooTools: How to use responseText directly

    - by Johny
    In following example of code, I want to traverse the responseText object which consist the html code came from request_page.php file. In onSuccess event, i want to check whether < Div with id 'ersDiv' has any errors posted in it. new Request.HTML({ url: 'request_page.php', onSuccess: function(responseText, responseXML) { // My expected code to handle responseText object alert(errorMessage); }, onFailure: function() { } }); request_page.php file is like this : <div align='center'><div id='ersDiv'>Page loaded with insufficient data</div></div>

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  • pyramid traversal resource url no attribute __name__

    - by Santana
    So I have: resources.py: def _add(obj, name, parent): obj.__name__ = name obj.__parent__ = parent return obj class Root(object): __parent__ = __name__ = None def __init__(self, request): super(Root, self).__init__() self.request = request self.collection = request.db.post def __getitem__(self, key): if u'profile' in key: return Profile(self.request) class Profile(dict): def __init__(self, request): super(Profile, self).__init__() self.__name__ = u'profile' self.__parent__ = Root self.collection = request.db.posts def __getitem__(self, name): post = Dummy(self.collection.find_one(dict(username=name))) return _add(post, name, self) and I'm using MongoDB and pyramid_mongodb views.py: @view_config(context = Profile, renderer = 'templates/mytemplate.pt') def test_view(request): return {} and in mytemplate.pt: <p tal:repeat='item request.context'> ${item} </p> I can echo what's in the database (I'm using mongodb), but when I provided a URL for each item using resource_url() <p tal:repeat='item request.context'> <a href='${request.resource_url(item)}'>${item}</a> </p> I got an error: 'dict' object has no attribute '__name__', can someone help me?

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  • How to do a proper search with nhibernate

    - by Denis Rosca
    Hello everyone, i'm working on a small project that is supposed to allow basic searches of the database. Currently i'm using nhibernate for the database interaction. In the database i have 2 tables: Person and Address. The Person table has a many-to-one relationship with Address. The code i've come up with for doing searches is: public IList<T> GetByParameterList(List<QueryParameter> parameterList) { if (parameterList == null) { return GetAll(); } using (ISession session = NHibernateHelper.OpenSession()) { ICriteria criteria = session.CreateCriteria<T>(); foreach (QueryParameter param in parameterList) { switch (param.Constraint) { case ConstraintType.Less: criteria.Add(Expression.Lt(param.ParameterName, param.ParameterValue)); break; case ConstraintType.More: criteria.Add(Expression.Gt(param.ParameterName, param.ParameterValue)); break; case ConstraintType.LessOrEqual: criteria.Add(Expression.Le(param.ParameterName, param.ParameterValue)); break; case ConstraintType.EqualOrMore: criteria.Add(Expression.Ge(param.ParameterName, param.ParameterValue)); break; case ConstraintType.Equals: criteria.Add(Expression.Eq(param.ParameterName, param.ParameterValue)); break; case ConstraintType.Like: criteria.Add(Expression.Like(param.ParameterName, param.ParameterValue)); break; } } try { IList<T> result = criteria.List<T>(); return result; } catch { //TODO: Implement some exception handling throw; } } } The query parameter is a helper object that i use to create criterias and send it to the dal, it looks like this: public class QueryParameter { public QueryParameter(string ParameterName, Object ParameterValue, ConstraintType constraintType) { this.ParameterName = ParameterName; this.ParameterValue = ParameterValue; this.Constraint = constraintType; } public string ParameterName { get; set; } public Object ParameterValue { get; set; } public ConstraintType Constraint { get; set; } } Now this works well if i'm doing a search like FirstName = "John" , but not when i try to give a parameter like Street = "Some Street". It seems that nhibernate is looking for a street column in the Person table but not in the Address table. Any idea on how should i change my code for so i could do a proper search? Tips? Maybe some alternatives? Disclaimer: i'm kind of a noob so please be gentle ;) Thanks, Denis.

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  • Show up value of select option in IE

    - by Pete
    Hello, I have a problem with a html select object and its options in IE. My html <select id="Select1" onchange="closeMenu1(this.value)"> <option></option> <option>1</option> <option>2</option> And the javascript function closeMenu1 (x) { var show = document.getElementById("divID"); show.innerHTML = x; } Now, in every browser except the IEs the divID will show up the value which I selected in the select object. But IE doesn’t. Can somebody please tell me a way around that? Thanks.

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  • Can anyone recommend a .Net XML Serialization library?

    - by James
    Can anyone recommend a .Net XML Serialization library (ideally open source). I am looking for a robust XML serialization library that I can throw any object at, which will produce a human readable XML representation of the public properties for logging purposes. I never need to be able to deserialize. XmlSerializer's requirement of an object having a parameter constructor is too restrictive for what I want. DataContractSerializer does not give enough control over the output (which is not particularly human-readable). Any recommendations appreciated! Thanks

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  • Why are static classes considered “classes” and “reference types”?

    - by Timwi
    I’ve been pondering about the C# and CIL type system today and I’ve started to wonder why static classes are considered classes. There are many ways in which they are not really classes: A “normal” class can contain non-static members, a static class can’t. In this respect, a class is more similar to a struct than it is to a static class, and yet structs have a separate name. You can have a reference to an instance of a “normal” class, but not a static class (despite it being considered a “reference type”). In this respect, a class is more similar to an interface than it is to a static class, and yet interfaces have a separate name. The name of a static class can never be used in any place where a type name would normally fit: you can’t declare a variable of this type, you can’t use it as a base type, and you can’t use it as a generic type parameter. In this respect, static classes are somewhat more like namespaces. A “normal” class can implement interfaces. Once again, that makes classes more similar to structs than to static classes. A “normal” class can inherit from another class. It is also bizarre that static classes are considered to derive from System.Object. Although this allows them to “inherit” the static methods Equals and ReferenceEquals, the purpose of that inheritance is questionable as you would call those methods on object anyway. C# even allows you to specify that useless inheritance explicitly on static classes, but not on interfaces or structs, where the implicit derivation from object and System.ValueType, respectively, actually has a purpose. Regarding the subset-of-features argument: Static classes have a subset of the features of classes, but they also have a subset of the features of structs. All of the things that make a class distinct from the other kinds of type, do not seem to apply to static classes. Regarding the typeof argument: Making a static class into a new and different kind of type does not preclude it from being used in typeof. Given the sheer oddity of static classes, and the scarcity of similarities between them and “normal” classes, shouldn’t they have been made into a separate kind of type instead of a special kind of class?

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  • Is there a .NET BCL class to help with hand-rolled property path binding?

    - by Wayne
    WPF and Silverlight have a data binding model whereby I can provide a Binding with a Path which comprises a dot-notation of property accessors down from a DataContext to a specific value inside a complex object graph (eg. MyDataContext.RootProperty.SubProperty.Thing.Value) I have a (non-UI) requirement to accept such a path expressed as a simple string, and to use reflection on an object which is (hopefully) of a type which exposes the right property getters and setters in order to read and/or write values to those properties. Before I go off and start writing the parser and reflection code, is there a handy Framework 3.5 BCL class to help with this?

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  • Rotating in OpenGL relative to the viewport

    - by Nick
    I'm trying to display an object in the view which can be rotated naturally by dragging the cursor/touchscreen. At the moment I've got X and Y rotation of an object like this glRotatef(rotateX, 0f, 1f, 0f); // Dragging along X, so spin around Y axis glRotatef(rotateY, 1f, 0f, 0f); I understand why this doesn't do what I want it to do (e.g. if you spin it right 180 degrees, up and down spinning gets reversed). I just can't figure out a way for both directions to stay left-right and up-down relative to the viewer. I can assume that the camera is fixed and looking along the Z axis. Any ideas?

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