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• VB.NET Button Issue

  - by Michael

  I am having problem with a button the code of my button is. Private Sub btnCalculateCosts_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCalculateCosts.Click it handles: ' This Calculate Costs button click event handler edits the ' registration(costs) form to ensure it contains valid data. ' Then, after passing control to the business class, it ' displays the registration cost. Dim objCourse As Course Dim objCourseCostsFile As Course Dim InputError As Boolean = False ' Is student ID entered properly If Me.txtCorporateID.MaskFull = False Then MessageBox.Show("Enter your Corporate ID in the Corporate ID box", _ "Error") Me.txtCorporateID.Clear() Me.txtCorporateID.Focus() InputError = True ' Is student name entered properly ElseIf Me.txtFirstName.TextLength < 1 Or _ Me.txtFirstName.Text < "A" Then MessageBox.Show("Please enter your first name in the First Name box", "Error") Me.txtFirstName.Clear() Me.txtFirstName.Focus() InputError = True ' Is number of units entered properly ElseIf Me.txtLastName.TextLength < 1 Or _ Me.txtLastName.Text < "A" Then MessageBox.Show("Please enter your last name in the Last Name box", "Error") Me.txtLastName.Clear() Me.txtLastName.Focus() InputError = True ' Is number of units entered properly ElseIf Not IsNumeric(Me.txtNumberOfDays.Text) Then MessageBox.Show("Enter the units in the Number of Units box", _ "Error") Me.txtNumberOfDays.Clear() Me.txtNumberOfDays.Focus() InputError = True ' Has 1-4 units been entered ElseIf Convert.ToInt32(Me.txtNumberOfDays.Text) < 1 _ Or Convert.ToInt32(Me.txtNumberOfDays.Text) > 4 Then MessageBox.Show("Units must be 1 - 4", "Error") Me.txtNumberOfDays.Clear() Me.txtNumberOfDays.Focus() InputError = True End If ' If no input error, process the registration costs If Not InputError Then If Me.radPreConferenceCourse.Checked = False Then objCourse = New Course(txtCorporateID.Text, txtFirstName.Text, txtLastName.Text, txtNumberOfDays.Text) Me.lblCosts.Visible = True Me.lblCosts.Text = "Total Conference Costs Are: " _ & (objCourse.ComputeCosts()).ToString("C2") Else objCourse = New Course(txtCorporateID.Text, txtFirstName.Text, txtLastName.Text, txtNumberOfDays.Text, g) Me.lblCosts.Visible = True Me.lblCosts.Text = "Total Conference Costs Are: " _ & (objCourse.ComputeCosts()).ToString("C2") Receiving the error: Handles clause requrieres a WithEvents variable defined in the containing type or one of its base types.

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• Returning JSON or XML for Exceptions in Jersey

  - by Dominic

  My goal is to have an error bean returned on a 404 with a descriptive message when a object is not found, and return the same MIME type that was requested. I have a look up resource, which will return the specified object in XML or JSON based on the URI (I have setup the com.sun.jersey.config.property.resourceConfigClass servlet parameter so I dont need the Accept header. My JAXBContextResolver has the ErrorBean.class in its list of types, and the correct JAXBContext is returned for this class because I can see in the logs). eg: http://foobar.com/rest/locations/1.json @GET @Path("{id}") @Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML}) public Location getCustomer(@PathParam("id") int cId) { //look up location from datastore .... if (location == null) { throw new NotFoundException("Location" + cId + " is not found"); } } And my NotFoundException looks like this: public class NotFoundException extends WebApplicationException { public NotFoundException(String message) { super(Response.status(Response.Status.NOT_FOUND). entity(new ErrorBean( message, Response.Status.NOT_FOUND.getStatusCode() ) .build()); } } The ErrorBean is as follows: @XmlRootElement(name = "error") public class ErrorBean { private String errorMsg; private int errorCode; //no-arg constructor, property constructor, getter and setters ... } However, I'm always getting a 204 No Content response when I try this. I have hacked around, and if I return a string and specify the mime type this works fine: public NotFoundException(String message) { super(Response.status(Response.Status.NOT_FOUND). entity(message).type("text/plain").build()); } I have also tried returning an ErrorBean as a resource. This works fine: {"errorCode":404,"errorMsg":"Location 1 is not found!"}

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• How should I map an abstract class with simple xml in Java?

  - by spderosso

  Hi, I want to achieve the following xml using simple xml framework (http://simple.sourceforge.net/): <events> <course-added date="01/01/2010"> ... </course-added> <course-removed date="01/02/2010"> .... </course-removed> <student-enrolled date="01/02/2010"> ... </student-enrolled> </events> I have the following (but it doesn't achieve the desired xml): @Root(name="events") class XMLEvents { @ElementList(inline=true) ArrayList<XMLEvent> events = Lists.newArrayList(); ... } abstract class XMLEvent { @Attribute(name="date") String dateOfEventFormatted; ... } And different type of XMLNodes that have different information (but are all different types of events) @Root(name="course-added") class XMLCourseAdded extends XMLEvent{ @Element(name="course") XMLCourseLongFormat course; .... } @Root(name="course-removed") class XMLCourseRemoved extends XMLEvent { @Element(name="course-id") String courseId; ... } How should I do the mapping or what should I change in order to be able to achieve de desired xml? Thanks!

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• How to get a category listing from Magento?

  - by alex

  I want to create a page in Magento that shows a visual representation of the categories.. example CATEGORY product 1 product 2 ANOTHER CATEGORY product 3 My problem is, their database is organised very differently to what I've seen in the past. They have tables dedicated to data types like varchar, int, etc. I assume this is for performance or similiar. I haven't found a way to use MySQL to query the database and get a list of categories. I'd then like to match these categories to products, to get a listing of products for each category. Unfortunately Magento seems to make this very difficult. Also I have not found a method that will work from within a page block.. I have created showcase.phtml and put it in the XML layout and it displays and runs it's PHP code. I was hoping for something easy like looping through $this-getAllCategories(); and then a nested loop inside with something like $category-getChildProducts(); Can anyone help me? Thank you!

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• Do I need to using locking against integers in c++ threads

  - by Shane MacLaughlin

  The title says it all really. If I am accessing a single integer type (e.g. long, int, bool, etc...) in multiple threads, do I need to use a synchronisation mechanism such as a mutex to lock them. My understanding is that as atomic types, I don't need to lock access to a single thread, but I see a lot of code out there that does use locking. Profiling such code shows that there is a significant performance hit for using locks, so I'd rather not. So if the item I'm accessing corresponds to a bus width integer (e.g. 4 bytes on a 32 bit processor) do I need to lock access to it when it is being used across multiple threads? Put another way, if thread A is writing to integer variable X at the same time as thread B is reading from the same variable, is it possible that thread B could end up a few bytes of the previous value mixed in with a few bytes of the value being written? Is this architecture dependent, e.g. ok for 4 byte integers on 32 bit systems but unsafe on 8 byte integers on 64 bit systems? Edit: Just saw this related post which helps a fair bit.

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• Using "as bool?" instead of "object something = ViewState["hi"]"

  - by Programmin Tool

  So I'm going through old code (2.0) and I came across this: object isReviewingValue = ViewState["IsReviewing"]; if (isReviewingValue is bool) { return (bool)isReviewingValue; } My first thought was to us the "as" keyword to avoid the unneeded (bool)isReviewingValue; But "as" only works with non value types. No problem, I just went ahead and did this: bool? isReviewingValue= ViewState["IsReviewing"] as bool?; if (isReviewingValue.HasValue) { return isReviewingValue.Value; } Question is: Besides looking a bit more readable, is this in fact better? EDIT: So this is getting more interesting. I decided to test it using a simple stopwatch and turns out that the second is much faster... Which after reading some of the responses here I didn't expect at all. I was thinking for sure my way was much slower. Tell me what I did wrong: public Stopwatch AsRun() { Stopwatch watch = new Stopwatch(); watch.Start(); for (Int32 loopCounter = 0; loopCounter < 10000; loopCounter++) { Boolean? test = true as Boolean?; if (test.HasValue) { Boolean something = test.Value; } } watch.Stop(); return watch; } public Stopwatch ObjectIsRun() { Stopwatch watch = new Stopwatch(); watch.Start(); for (Int32 loopCounter = 0; loopCounter < 10000; loopCounter++) { Object test = true; if (test is Boolean) { Boolean something = (Boolean)test; } } watch.Stop(); return watch; } Every time I run these methods against each other, the AsRun is twice as fast.

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• Why do we need serialization in web service

  - by Cloud2010

  I have one webservice: public class Product { public int ProductId { get; set; } public string ProductName { get; set; } } public class Service : System.Web.Services.WebService { public Service () { //Uncomment the following line if using designed components //InitializeComponent(); } [WebMethod] public List<Product> GetItems() { List<Product> productList = new List<Product>() { new Product{ProductId=1,ProductName="Pencil"}, new Product{ProductId=2,ProductName="Pen"} }; return productList; } and in a asp.net application I am consuming it like: localhost.Service s = new localhost.Service(); List<localhost.Product> k = new List<localhost.Product>(); k = s.GetItems().ToList(); // i am getting the values here. now my question is do I need to serialize my webmethod as i am returning custom types? when should we serialize ? is it necessary at all, if yes , then what are the conditions?

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• Is this a good way to generically deserialize objects?

  - by Damien Wildfire

  I have a stream onto which serialized objects representing messages are dumped periodically. The objects are one of a very limited number of types, and other than the actual sequence of bytes that arrives, I have no way of knowing what type of message it is. I would like to simply try to deserialize it as an object of a particular type, and if an exception is thrown, try again with the next type. I have an interface that looks like this: public interface IMessageHandler<T> where T : class, IMessage { T Handle(string message); } // elsewhere: // (These are all xsd.exe-generated classes from an XML schema.) public class AppleMessage : IMessage { ... } public class BananaMessage : IMessage { ... } public class CoconutMessage : IMessage { ... } Then I wrote a GenericHandler<T> that looks like this: public class GenericHandler<T> : IMessageHandler<T> where T: class, IMessage { public class MessageHandler : IMessageHandler { T IMessageHandler.Handle(string message) { T result = default(T); try { // This utility method tries to deserialize the object with an // XmlSerializer as if it were an object of type T. result = Utils.SerializationHelper.Deserialize<T>(message); } catch (InvalidCastException e) { result = default(T); } return result; } } } Two questions: Using my GenericHandler<T> (or something similar to it), I'd now like to populate a collection with handlers that each handle a different type. Then I want to invoke each handler's Handle method on a particular message to see if it can be deserialized. If I get a null result, move onto the next handler; otherwise, the message has been deserialized. Can this be done? Is there a better way to deserialize data of unknown (but restricted) type?

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• Getting the current item number or index when using will_paginate in rails app

  - by Rich

  I have a rails app that stores movies watched, books read, etc. The index page for each type lists paged collections of all its items, using will_paginate to bring back 50 items per page. When I output the items I want to display a number to indicate what item in the total collection it is. The numbering should be reversed as the collection is displayed with most recent first. This might not relate to will_paginate but rather some other method of calculation. I will be using the same ordering in multiple types so it will need to be reusable. As an example, say I have 51 movies. The first item of the first page should display: Fight Club - Watched: 30th Dec 2010 Whilst the last item on the page should display: The Matrix - Watched: 3rd Jan 2010 The paged collection is available as an instance variable e.g. @movies, and @movies.count will display the number of items in the paged collection. So if we're on page 1, movies.count == 50, whilst on page 2 @movies.count == 1. Using Movie.count would give 51. If the page number and page size can be accessed the number could be calculated so how can they be returned? Though I'm hopeful there is something that already exists to handle this calculation!

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• Passing a string to a function in C++

  - by Chef Flambe

  I want to pass a string like "Celcius" into a function that I have but I keep getting errors tossed back at me from the Function. System::Console::WriteLine' : none of the 19 overloads could convert all the argument types I figure I just have something simple wrong. Can someone point out my mistake please? Using MS Visual C++ 2010 I've posted the offending code. The other functions (not posted) work fine. void PrintResult( double result, std::string sType ); // Print result and string // to the console //============================================================================================= // start of main //============================================================================================= void main( void ) { ConsoleKeyInfo CFM; // Program Title and Description ProgramDescription(); // Menu Selection and calls to data retrieval/calculation/result Print CFM=ChooseFromMenu(); switch(CFM.KeyChar) // ************************************************************ { //* case '1' : PrintResult(F2C(GetTemperature()),"Celsius"); //* break; //* //* case '2' : PrintResult(C2F(GetTemperature()),"Fahrenheit"); //* break; //* //* default : Console::Write("\n\nSwitch : Case !!!FAILURE!!!"); //* } //************************************************************ system("pause"); return; } //Function void PrintResult( double result, std::string sType ) { Console::WriteLine("\n\nThe converted temperature is {0:F2} degrees {1}\n\n",result,sType); return; }

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• refactoring my code. My headers (Header Guard Issues)

  - by numerical25

  I had a post similar to this awhile ago based on a error I was getting. I was able to fix it but since then I been having trouble doing things because headers keep blocking other headers from using code. Honestly, these headers are confusing me and if anyone has any resources that will address these types of issues, that will be helpful. What I essentially want to do is be able to have rModel.h be included inside RenderEngine.h. every time I add rModel.h to RenderEngine.h, rModel.h is no longer able to use RenderEngine.h. (rModel.h has a #include of RenderEngine.h as well). So in a nutshell, RenderEngine and rModel need to use each others functionalities. On top of all this confusion, the Main.cpp needs to use RenderEngine. stdafx.h #include "targetver.h" #define WIN32_LEAN_AND_MEAN // Exclude rarely-used stuff from Windows headers // Windows Header Files: #include <windows.h> // C RunTime Header Files #include <stdlib.h> #include <malloc.h> #include <memory.h> #include <tchar.h> #include "resource.h" main.cpp #include "stdafx.h" #include "RenderEngine.h" #include "rModel.h" // Global Variables: RenderEngine go; rModel *g_pModel; ...code........... rModel.h #ifndef _MODEL_H #define _MODEL_H #include "stdafx.h" #include <vector> #include <string> #include "rTri.h" #include "RenderEngine.h" ........Code RenderEngine.h #pragma once #include "stdafx.h" #include "d3d10.h" #include "d3dx10.h" #include "dinput.h" #include "rModel.h" .......Code......

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• Most Efficient way to deal with multiple CCSprites?

  - by nardsurfer

  I have four different types of objects within my environment(box2d), each type of object having multiple instances of itself, and would like to find the most efficient way to deal with adding and manipulating all the CCSprites. The sprites are all from different files, so would it be best to create each sprite and add it to a data structure (NSMutableArray) or would I use a CCSpriteBatchNode even though each CCSprite file is different (for each type of object)? Thanks. @interface LevelScene : CCLayer { b2World* world; GLESDebugDraw *m_debugDraw; CCSpriteBatchNode *ballBatch; CCSpriteBatchNode *blockBatch; CCSpriteBatchNode *springBatch; CCSprite *goal; } +(id) scene; // adds a new sprite at a given coordinate -(void) addNewBallWithCoords:(CGPoint)p; // loads the objects (blocks, springs, and the goal), returns the Level Object -(Level) loadLevel:(int)level; @end or using NSMutableArray objects within the Level object... @interface zLevel : zThing { NSMutableArray *springs; NSMutableArray *blocks; NSMutableArray *balls; zGoal *goal; int levelNumber; } @property(nonatomic,retain)NSMutableArray *springs; @property(nonatomic,retain)NSMutableArray *blocks; @property(nonatomic,retain)NSMutableArray *balls; @property(nonatomic,retain)zGoal *goal; @property(nonatomic,assign)int levelNumber; -(void)initWithLevel:(int)level; -(void)loadLevelThings; @end

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• C++ universal data type

  - by Gokul

  I have a universal data type, which is passed by value, but does not maintain the type information. We store only pointers and basic data types(like int, float etc) inside this. Now for the first time, we need to store std::string inside this. So we decided to convert it into std::string* and store it. Then comes the problem of destruction. We don't like to copy the std::string every time. So i am thinking of an approach like this. Say the data type looks like this class Atom { public : enum flags { IS_STRING, IS_EMPTY, HAS_GOT_COPIED, MARKER }; private: void* m_value; std::bitset<MARKER> m_flags; public: ..... Atom( Atom& atm ) { atm.m_flags.set( HAS_GOT_COPIED ); ..... } ..... ~Atom() { if( m_flags.test(IS_STRING) && !m_flags.test(HAS_GOT_COPIED) ) { std::string* val = static_cast<std::string*>(m_value); delete val; } } }; Is this a good approach to find out whether there is no more reference to std::string*? Any comments.. Thanks, Gokul.

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• Overhead of calling tiny functions from a tight inner loop? [C++]

  - by John

  Say you see a loop like this one: for(int i=0; i<thing.getParent().getObjectModel().getElements(SOME_TYPE).count(); ++i) { thing.getData().insert( thing.GetData().Count(), thing.getParent().getObjectModel().getElements(SOME_TYPE)[i].getName() ); } if this was Java I'd probably not think twice. But in performance-critical sections of C++, it makes me want to tinker with it... however I don't know if the compiler is smart enough to make it futile. This is a made up example but all it's doing is inserting strings into a container. Please don't assume any of these are STL types, think in general terms about the following: Is having a messy condition in the for loop going to get evaluated each time, or only once? If those get methods are simply returning references to member variables on the objects, will they be inlined away? Would you expect custom [] operators to get optimized at all? In other words is it worth the time (in performance only, not readability) to convert it to something like: ElementContainer &source = thing.getParent().getObjectModel().getElements(SOME_TYPE); int num = source.count(); Store &destination = thing.getData(); for(int i=0;i<num;++i) { destination.insert(thing.GetData().Count(), source[i].getName(); } Remember, this is a tight loop, called millions of times a second. What I wonder is if all this will shave a couple of cycles per loop or something more substantial? Yes I know the quote about "premature optimisation". And I know that profiling is important. But this is a more general question about modern compilers, Visual Studio in particular.

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• getting string.substring(N) not to choke when N > string.length

  - by aape

  I'm writing some code that takes a report from the mainframe and converts it to a spreadsheet. They can't edit the code on the MF to give me a delimited file, so I'm stuck dealing with it as fixed width. It's working okay now, but I need to get it more stable before I release it for testing. My problem is that in any given line of data, say it could have three columns of numbers, each five chars wide at positions 10, 16, and 22. If on this one particular row, there's no data for the last two cols, it won't be padded with spaces; rather, the length of the string will be only 14. So, I can't just blindly have dim s as string = someStream.readline a = s.substring(10, 5) b = s.substring(16, 5) c = s.substring(22, 5) because it'll choke when it substrings past the length of the string. I know I could test the length of the string before processing each row, and I have automated the filling of some of the vsariables using a counter and a loop, and using the counter*theWidthOfTheGivenVariable to jump around, but this project was a dog to start with (come on! turning a report into a spreadsheet?), but there are many different types of rows (it's not just a grid), and the code's getting ugly fast. I'd like this to be clean, clear, and maintainable for the poor sucker that gets this after me. If it matters, here's my code so far (it's really crufty at the moment). You can see some of my/its idiocy in the processSection#data subs So, I'm wondering 1) is there a way baked in to .NET to have string.substring not error when reading past the end of a string without wrapping it in a try...catch? and 2) would it be appropriate in this situation to write a new string class that inherits from string that has a more friendly substring function in it? ETA: Thanks for all the advice and knowledge everyone. I'll go with the extension. Hopefully one of these years, I'll get my chops up enough to pay someone back in kind. :)

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• And now for a complete change of direction from C++ function pointers

  - by David

  I am building a part of a simulator. We are building off of a legacy simulator, but going in different direction, incorporating live bits along side of the simulated bits. The piece I am working on has to, effectively route commands from the central controller to the various bits. In the legacy code, there is a const array populated with an enumerated type. A command comes in, it is looked up in the table, then shipped off to a switch statement keyed by the enumerated type. The type enumeration has a choice VALID_BUT_NOT_SIMULATED, which is effectively a no-op from the point of the sim. I need to turn those no-ops into commands to actual other things [new simulated bits| live bits]. The new stuff and the live stuff have different interfaces than the old stuff [which makes me laugh about the shill job that it took to make it all happen, but that is a topic for a different discussion]. I like the array because it is a very apt description of the live thing this chunk is simulating [latching circuits by row and column]. I thought that I would try to replace the enumerated types in the array with pointers to functions and call them directly. This would be in lieu of the lookup+switch.

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• sockaddr_in causing segfault?

  - by Curlystraw

  Working on creating a server/client system in C right now, and I'm having a little trouble with the client part. From what I've seen, I need to use sockaddr_in so I can connect to the server. However, I've been getting a segfault every time. I believe that sockaddr_in has something to do with it, as comment it and it's references later in the program fixes the segfault. code: #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <unistd.h> #include <netinet/in.h> int main(int argc, char** argv) { int Csock; int con; char *data = 0; char buf[101] = ""; struct sockaddr_in addr; Csock = socket(AF_INET, SOCK_STREAM, 0); addr.sin_family = AF_INET; addr.sin_port = htons(3435); con = connect(Csock, (struct sockaddr*) &addr, sizeof(&addr)); write(con, "Text", sizeof("Text")); *data = read(con, buf, 100); puts(data); return 0; } sadly, I am rather new to C, so that's as much as I can figure... can anyone tell me a way to go about eliminating the segfault? Thanks!

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• "Address of" (&) an array / address of being ignored be gcc?

  - by dbarbosa

  Hi, I am a teaching assistant of a introductory programming course, and some students made this type of error: char name[20]; scanf("%s",&name); which is not surprising as they are learning... What is surprising is that, besides gcc warning, the code works (at least this part). I have been trying to understand and I wrote the following code: void foo(int *str1, int *str2) { if (str1 == str2) printf("Both pointers are the same\n"); else printf("They are not the same\n"); } int main() { int test[50]; foo(&test, test); if (&test == test) printf("Both pointers are the same\n"); else printf("They are not the same\n"); } Compiling and executing: $ gcc test.c -g test.c: In function ‘main’: test.c:12: warning: passing argument 1 of ‘foo’ from incompatible pointer type test.c:13: warning: comparison of distinct pointer types lacks a cast $ ./a.out Both pointers are the same Both pointers are the same Can anyone explain why they are not different? I suspect it is because I cannot get the address of an array (as I cannot have & &x), but in this case the code should not compile.

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• ASP.NET Custom Control - Template Allowing Literal Content

  - by Bob Fincheimer

  I want my User Control to be able to have Literal Content inside of it. For Example: <fc:Text runat="server">Please enter your login information:</fc:Text> Currently the code for my user control is: <ParseChildren(True, "Content")> _ Partial Public Class ctrFormText Inherits FormControl Private _content As ArrayList <PersistenceMode(PersistenceMode.InnerDefaultProperty), _ DesignerSerializationVisibility(DesignerSerializationVisibility.Content), _ TemplateInstance(TemplateInstance.Single)> _ Public Property Content() As ArrayList Get If _content Is Nothing Then Return New ArrayList End If Return _content End Get Set(ByVal value As ArrayList) _content = value End Set End Property Protected Overrides Sub CreateChildControls() If _content IsNot Nothing Then ctrChildren.Controls.Clear() For Each i As Control In _content ctrChildren.Controls.Add(i) Next End If MyBase.CreateChildControls() End Sub End Class And when I put text inside this control (like above) i get this error: Parser Error Message: Literal content ('Please enter your login information to access CKMS:') is not allowed within a 'System.Collections.ArrayList'. This control could have other content than just the text, so making the Content property an attribute will not solve my problem. I found in some places that I need to implement a ControlBuilder Class, along with another class that implements IParserAccessor. Anyway I just want my default "Content" property to have all types of controls allowed in it, both literal and actual controls.

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• Create an index only on certain rows in mysql

  - by dhruvbird

  So, I have this funny requirement of creating an index on a table only on a certain set of rows. This is what my table looks like: USER: userid, friendid, created, blah0, blah1, ..., blahN Now, I'd like to create an index on: (userid, friendid, created) but only on those rows where userid = friendid. The reason being that this index is only going to be used to satisfy queries where the WHERE clause contains "userid = friendid". There will be many rows where this is NOT the case, and I really don't want to waste all that extra space on the index. Another option would be to create a table (query table) which is populated on insert/update of this table and create a trigger to do so, but again I am guessing an index on that table would mean that the data would be stored twice. How does mysql store Primary Keys? I mean is the table ordered on the Primary Key or is it ordered by insert order and the PK is like a normal unique index? I checked up on clustered indexes (http://dev.mysql.com/doc/refman/5.0/en/innodb-index-types.html), but it seems only InnoDB supports them. I am using MyISAM (I mention this because then I could have created a clustered index on these 3 fields in the query table). I am basically looking for something like this: ALTER TABLE USERS ADD INDEX (userid, friendid, created) WHERE userid=friendid

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• How to make restrictions on XML Schema Complex type?

  - by chobo2

  Hi I am reading the tutorials on w3cschools ( http://www.w3schools.com/schema/schema_complex.asp ) but they don't seem to mention how you could add restrictions on complex types. Like for instance I have this schema. <xs:element name="employee"> <xs:complexType> <xs:sequence> <xs:element name="firstname" type="xs:string"/> <xs:element name="lastname" type="xs:string"/> </xs:sequence> </xs:complexType> </xs:element> now I want to make sure the firstname is no more then 10 characters long. How do I do this? I tried to put in the simple type for the firstname but it says I can't do that since I am using a complex type. So how do I put restrictions like that on the file so the people who I give the schema to don't try to make the firstname 100 characters.

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• Best practice when removing entity regarding mappedBy collections?

  - by Daniel Bleisteiner

  I'm still kind of undecided which is the best practice to handle em.remove(entity) with this entity being in several collections mapped using mappedBy in JPA. Consider an entity like a Property that references three other entities: a Descriptor, a BusinessObject and a Level entity. The mapping is defined using @ManyToOne in the Property entity and using @OneToMany(mappedBy...) in the other three objects. That inverse mapping is defined because there are some situations where I need to access those collections. Whenever I remove a Property using em.remove(prop) this element is not automatically removed from managed entities of the other three types. If I don't care about that and the following page load (webapp) doesn't reload those entities the Property is still found and some decisions might be taken that are no longer true. The inverse mappings may become quite large and though I don't want to use something like descriptor.getProperties().remove(prop) because it will load all those properties that might have been lazy loaded until then. So my currently preferred way is to refresh the entity if it is managed: if (em.contains(descriptor)) em.refresh(descriptor) - which unloads a possibly loaded collection and triggers a reload upon the next access. Is there another feasible way to handle all those mappedBy collections of already loaded entites?

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• Design Pattern for Changing Object

  - by user210757

  Is there a Design Pattern for supporting different permutations object? Version 1 public class myOjbect { public string field1 { get; set; } /* requirements: max length 20 */ public int field2 { get; set; } . . . public decimal field200 { get; set; } } Version 2 public class myObject { public string field1 { get; set; } /* requirements: max length 40 */ public int field2 { get; set; } . . . public double field200 { get; set; } /* changed data types */ . . ./* 10 new properties */ public double field210 { get; set; } } of course I could just have separate objects, but thought there might be a good pattern for this sort of thing.

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• Alternative to Altova's MissionKit

  - by nomad311

  Anyone know of any good alternatives (other than those listed below which really are only good at specific XML development tasks)? The Why (if you're interested): I've been doing XML development on and off for years now, but someone brought XMLSpy to my attention recently, and it is awesome - the price isn't. Lately I've been using a combination of: Notepad++ (modifying XML) EditX (validating/debugging XML) Eclipse (designing schemas) and MS Visual Studio (validating schemas) ...based on which makes the task(s) easiest. But, I've just found out that we will be using XSL transformations to generate XML in the future. I've never used mission kit before, but I'm just short of positive XMLSpy replaces all the above mentioned tool for XML development. And if their XSL tools are anywhere near the caliber of XMLSpy ...simply put I need it. I don't believe that I can convince the budgeting types to buy licenses for MissionKit at $1000 each (won't stop me from trying). In the mean while some research on alternatives won't hurt, but a few Google queries has only revealed that not many people pay for Altova's (overpriced?) software as there are mostly links to P2P sites for downloading a more free-like version of MissionKit.

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• interface abstract in php real world scenario

  - by jason

  The goal is to learn whether to use abstract or interface or both... I'm designing a program which allows a user to de-duplicate all images but in the process rather then I just build classes I'd like to build a set of libraries that will allow me to re-use the code for other possible future purposes. In doing so I would like to learn interface vs abstract and was hoping someone could give me input into using either. Here is what the current program will do: recursive scan directory for all files determine file type is image type compare md5 checksum against all other files found and only keep the ones which are not duplicates Store total duplicates found at the end and display size taken up Copy files that are not duplicates into folder by date example Year, Month folder with filename is file creation date. While I could just create a bunch of classes I'd like to start learning more on interfaces and abstraction in php. So if I take the scan directory class as the first example I have several methods... ScanForFiles($path) FindMD5Checksum() FindAllImageTypes() getFileList() The scanForFiles could be public to allow anyone to access it and it stores in an object the entire directory list of files found and many details about them. example extension, size, filename, path, etc... The FindMD5Checksum runs against the fileList object created from scanForFiles and adds the md5 if needed. The FindAllImageTypes runs against the fileList object as well and adds if they are image types. The findmd5checksum and findallimagetypes are optionally run methods because the user might not intend to run these all the time or at all. The getFileList returns the fileList object itself. While I have a working copy I've revamped it a few times trying to figure out whether I need to go with an interface or abstract or both. I'd like to know how an expert OO developer would design it and why?

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