Search Results

Search found 4593 results on 184 pages for 'operator equal'.

Page 149/184 | < Previous Page | 145 146 147 148 149 150 151 152 153 154 155 156  | Next Page >

  • C++ stack for multiple data types (RPN vector calculator)

    - by Arrieta
    Hello: I have designed a quick and basic vector arithmetic library in C++. I call the program from the command line when I need a rapid cross product, or angle between vectors. I don't use Matlab or Octave or related, because the startup time is larger than the computation time. Again, this is for very basic operations. I am extending this program, and I will make it work as an RPN calculator, for operations of the type: 1 2 3 4 5 6 x out: -3 6 -3 (give one vector, another vector, and the "cross" operator; spit out the cross product) The stack must accept 3d vectors or scalars, for operations like: 1 2 3 2 * out: 2 4 6 The lexer and parser for this mini-calculator are trivial, but I cannot seem to think of a good way for creating the internal stack. How would you create a stack of for containing vectors or doubles (I rolled up my own very simple vector class - less than one hundred lines and it does everything I need). How can I create a simple stack which accepts elements of class Vector or type double? Thank you.

    Read the article

  • Is this a clean way to manage AsyncResults with Generic Methods?

    - by Michael Stum
    I've contributed Async Support to a Project I'm using, but I made a bug which I'm trying to fix. Basically I have this construct: private readonly Dictionary<WaitHandle, object> genericCallbacks = new Dictionary<WaitHandle, object>(); public IAsyncResult BeginExecute<T>(RestRequest request, AsyncCallback callback, object state) where T : new() { var genericCallback = new RequestExecuteCaller<T>(this.Execute<T>); var asyncResult = genericCallback.BeginInvoke(request, callback, state); genericCallbacks[asyncResult.AsyncWaitHandle] = genericCallback; return asyncResult; } public RestResponse<T> EndExecute<T>(IAsyncResult asyncResult) where T : new() { var cb = genericCallbacks[asyncResult.AsyncWaitHandle] as RequestExecuteCaller<T>; genericCallbacks.Remove(asyncResult.AsyncWaitHandle); return cb.EndInvoke(asyncResult); } So I have a generic BeginExecute/EndExecute method pair. As I need to store the delegate that is called on EndExecute somewhere I created a dictionary. I'm unsure about using WaitHandles as keys though, but that seems to be the only safe choice. Does this approach make sense? Are WaitHandles unique or could I have two equal ones? Or should I instead use the State (and wrap any user provided state into my own State value)? Just to add, the class itself is non-generic, only the Begin/EndExecute methods are generic.

    Read the article

  • Binder and variadic template ends up in a segmentation fault

    - by phlipsy
    I wrote the following program #include <iostream> template<typename C, typename Res, typename... Args> class bind_class_t { private: Res (C::*f)(Args...); C *c; public: bind_class_t(Res (C::*f)(Args...), C* c) : f(f), c(c) { } Res operator() (Args... args) { return (c->*f)(args...); } }; template<typename C, typename Res, typename... Args> bind_class_t<C, Res, Args...> bind_class(Res (C::*f)(Args...), C* c) { return bind_class<C, Res, Args...>(f, c); } class test { public: int add(int x, int y) { return x + y; } }; int main() { test t; // bind_class_t<test, int, int, int> b(&test::add, &t); bind_class_t<test, int, int, int> b = bind_class(&test::add, &t); std::cout << b(1, 2) << std::endl; return 0; } compiled it with gcc 4.3.3 and got a segmentation fault. After spending some time with gdb and this program it seems to me that the addresses of the function and the class are mixed up and a call of the data address of the class isn't allowed. Moreover if I use the commented line instead everything works fine. Can anyone else reproduce this behavior and/or explain me what's going wrong here?

    Read the article

  • Fetching Core Data for Tableview on iPhone - Tutorial leaves me with crashes when adding items to a

    - by Gordon Fontenot
    Been following the Core Data tutorial on Apple's developer site, and all is good until I have to add something to the fetched store. I am getting this error after a successful build and load when I try to add a new item to the list: Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section after the update (0) must be equal to the number of rows contained in that section before the update (0), plus or minus the number of rows inserted or deleted from that section (1 inserted, 0 deleted). Due to the fact that the fetch goes through fine, and that if I replace the fetching with eventList = [[NSMutableArray alloc] init] it works as expected (without persistance, of course), I am led to believe that the problem comes from not creating the Mutable Array correctly. Here's the problematic part of the code: NSFetchRequest *request = [[NSFetchRequest alloc] init]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"Event" inManagedObjectContext:managedObjectContext]; [request setEntity:entity]; NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"creationDate" ascending:NO]; NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil]; [request setSortDescriptors:sortDescriptors]; [sortDescriptors release]; [sortDescriptor release]; NSError *error; NSMutableArray *mutableFetchResults = [[managedObjectContext executeFetchRequest:request error:&error] mutableCopy]; if (mutableFetchResults = nil) { //Handle the error } [self setEventList:mutableFetchResults]; [mutableFetchResults release]; [request release]; I have tried switching the NSArrays in the second chunk out with NSMutableArrays, but I still get the same error. For reference, the section of code that is throwing the error when I try adding an entry is here: [eventList insertObject:event atIndex:0]; NSIndexPath *indexPath = [NSIndexPath indexPathForRow:0 inSection:0]; [self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade]; [self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:YES]; it errors out at the insertRowsAtIndexPaths call. Thanks in advance for any help

    Read the article

  • Custom Jquery slideshow doesn't want to reset?

    - by Jared
    Hello, Under $(document).ready(function(), I have the following code: num = $("#mainContentCategoryLinksWrapper > div").size(); This makes num equal the length of the children of #mainContentCategoryLinksWrapper. Currently, this equals 4. Above the $(document).ready(function( I have this: var timesRun = 0; function slideshow(){ if(timesRun < num){ $(".arrowIn").stop().animate({color: "#a12324", textIndent: "30px", backgroundPosition: '0px 0px'}, 100, function(){ //the first child in the series has a class of "arrowIn" $(".arrowIn").next().addClass("replaceMe"); //Adds the ".replaceMe" placeholder the the next element. $(".arrowIn").removeClass("arrowIn"); //Deletes the class on the current element $(".replaceMe").addClass("arrowIn").removeClass("replaceMe"); //reassigns ".arrowIn" over ".replaceMe" timesRun = timesRun + 1; //increases number of times run }).prev().animate({color: "#000000", textIndent: "25px", backgroundPosition: '0px -25px'}, {duration: 50}); //puts the previous element back to it's original position }else{ timesRun = 0; $(".arrowIn").removeClass("arrowIn"); $("#mainContentCategoryLinksWrapper:first-child").addClass("arrowIn"); //this is supposed to reset timesRun, and set the first child in the series back to the original ".arrowIn" } } setInterval( 'slideshow()', 1000 ); So here is the what the code does: 1) Animates the first in the series of 4 (#1) timesRun = 1 2) Animates the second in the series of 4 (#2) timesRun = 2 3) Animates the third in the series of 4 (#3) timesRun = 3 4) Animates the fourth in the series of 4 (#4) timesRun = 4 5) timesRun is now longer less than num. Reset class names back to original to .arrowIn, set timesRun to 0. However, when the slideshow() is reexectuted, it doesn't start over. Any ideas? See www.raceramps.com/v3 for an example.

    Read the article

  • how is data stored at bit level according to "Endianness" ?

    - by bakra
    I read about Endianness and understood squat... so I wrote this main() { int k = 0xA5B9BF9F; BYTE *b = (BYTE*)&k; //value at *b is 9f b++; //value at *b is BF b++; //value at *b is B9 b++; //value at *b is A5 } k was equal to "A5 B9 BF 9F" and (byte)pointer "walk" o/p was "9F BF b9 A5" so I get it bytes are stored backwards...ok. ~ so now I thought how is it stored at BIT level... I means is "9f"(1001 1111) stored as "f9"(1111 1001)? so I wrote this int _tmain(int argc, _TCHAR* argv[]) { int k = 0xA5B9BF9F; void *ptr = &k; bool temp= TRUE; cout<<"ready or not here I come \n"< for(int i=0;i<32;i++) { temp = *( (bool*)ptr + i ); if( temp ) cout<<"1 "; if( !temp) cout<<"0 "; if(i==7||i==15||i==23) cout<<" - "; } } I get some random output even for nos. like "32" I dont get anything sensible. why ?

    Read the article

  • Strangely structured xml code finding last value of a certain type using java

    - by Damien.Bell
    Thus the structure is something like this: OasisReportMessagePayloadRTOReport_ItemReport_Data Under report data it's broken into categories: >>Zone >>Type >>Value >>Interval What I need to do is: Get the value if the type is equal to 'myType' and the interval value is the LARGEST. So an example of the xml might be (under report_data): OasisReport MessagePayload RTO REPORT_ITEM REPORT_DATA <zone>myZone1</zone> -- This should be the same in all reports since I only get them for 1 zone <type>myType</type> --This can change from line to line <value>12345</value>--This changes every interval <Interval>122</Interval> -- This is essentially how many 5 minute intervals have taken place since the beginning of a day, finding the "max" lets me know it's the newest data. Thereby I want to find stuff of "MyType" for the "max" interval and pull the Value (into a string, or a double, if not I can convert from string. Can someone help me with this task? Thanks! Note: I've used Xpath to handle things like this in the past, but it seems outlandish for this... as it's SO complex (since not all the reports live in the same report_item, and not all the types are the same in each report)

    Read the article

  • .NET Thread.Abort again

    - by hoodoos
    Again I want to talk about safety of the Thread.Abort function. I was interested to have some way to abort operations which I can't control really and don't want actually, but I want to have my threads free as soon as possible to prevent thread thirsty of my application. So I wrote some test code to see if it's possible to use Thread.Abort and have the aborting thread clean up resources propertly. Here's code: int threadRunCount = 0; int threadAbortCount = 0; int threadFinallyCount = 0; int iterations = 0; while( true ) { Thread t = new Thread( () => { threadRunCount++; try { Thread.Sleep( Random.Next( 45, 55 ) ); } catch( ThreadAbortException ) { threadAbortCount++; } finally { threadFinallyCount++; } } ); t.Start(); Thread.Sleep( 45 ); t.Abort(); iterations++; } So, so far this code worked for about 5 mins, and threadRunCount was always equal to threadFinally and threadAbort was somewhat lower in number, because some threads completed with no abort or probably got aborted in finally. So the question is, do I miss something?

    Read the article

  • django - variable declared in base project does not appear in app

    - by unsorted
    I have a variable called STATIC_URL, declared in settings.py in my base project: STATIC_URL = '/site_media/static/' This is used, for example, in my site_base.html, which links to CSS files as follows: <link rel="stylesheet" href="{{ STATIC_URL }}css/site_tabs.css" /> I have a bunch of templates related to different apps which extend site_base.html, and when I look at them in my browser the CSS is linked correctly as <link rel="stylesheet" href="/site_media/static/css/site_tabs.css" /> (These came with a default pinax distribution.) I created a new app called 'courses' which lives in the ...../apps/courses folder. I have a view for one of the pages in courses called courseinstance.html which extends site_base.html just like the other ones. However, when this one renders in my browser it comes out as <link rel="stylesheet" href="css/site_tabs.css" /> as if STATIC_URL were equal to "" for this app. Do I have to make some sort of declaration to get my app to take on the same variable values as the project? I don't have a settings.py file for the app. by the way, the app is listed in my list of INSTALLED_APPS and it gets served up fine, just without the link to the CSS file (so the page looks funny). Thanks in advance for your help.

    Read the article

  • Problem with using malloc in link lists (urgent ! help please)

    - by Abhinav
    I've been working on this program for five months now. Its a real time application of a sensor network. I create several link lists during the life of the program and Im using malloc for creating a new node in the link. What happens is that the program suddenly stops or goes crazy and restarts. Im using AVR and the microcontroller is ATMEGA 1281. After a lot of debugging I figured out that that the malloc is causing the problem. I do not free the memory after exiting the function that creates a new link so Im guessing that this is eventually causing the heap memory to overflow or something like that. Now if I use the free() function to deallocate the memory at the end of the function using malloc, the program just gets stuck when the control reaches free(). Is this because the memory becomes too clustered after calling free() ? I also create reference tables for example if 'head' is a new link list and I create another list called current and make it equal to head. table *head; table *current = head; After the end of the function if I use free free(current); current = NULL: Then the program gets stuck here. I dont know what to do. What am I doing wrong? Is there a way to increase the size of the heap memory Please help...

    Read the article

  • can't increment Glib::ustring::iterator (getting "invalid lvalue in increment" compiler error)

    - by davka
    in the following code: int utf8len(char* s, int len) { Glib::ustring::iterator p( string::iterator(s) ); Glib::ustring::iterator e ( string::iterator(s+len) ); int i=0; for (; p != e; p++) // ERROR HERE! i++; return i; } I get the compiler error on the for line, which is sometimes "invalid lvalue in increment", and sometimes "ISO C++ forbids incrementing a pointer of type etc... ". Yet, the follwing code: int utf8len(char* s) { Glib::ustring us(s); int i=0; for (Glib::ustring::iterator p = us.begin(); p != us.end(); p++) i++; return i; } compiles and works fine. according the Glib::ustring documentation and the include file, ustring iterator can be constructed from std::string iterator, and has operator++() defined. Weird? BONUS QUESTION :) Is there a difference in C++ between the 2 ways of defining a variable: classname ob1( initval ); classname ob1 = initval; I believed that they are synonymous; yet, if I change Glib::ustring::iterator p( string::iterator(s) ); to Glib::ustring::iterator p = string::iterator(s); I get a compiler error (gcc 4.1.2) conversion from ‘__gnu_cxx::__normal_iterator, std::allocator ’ to non-scalar type ‘Glib::ustring_Iterator<__gnu_cxx::__normal_iterator, std::allocator ’ requesed thanks a lot!

    Read the article

  • How to pass a value from the Jquery validation

    - by user2963960
    How can i pass a value from the jquery validation. I have an input box named clubCardNumber it should validate the length of the inputted value. If the length is equal to 10 the value passes to the hidden field named else validated it if its null or empty if all validations are true then its a clubCard. Here is how i implemented it on Javascript function validateClubCardNumber() { var varClubCardNumber = $('#clubCardNumber').val(); $('#phoneNumber').val(""); var returnVal = true; if ((null == varClubCardNumber || '' == trim(varClubCardNumber)){ return false; } if( varClubCardNumber.length < 10 ){ return false; }else if( varClubCardNumber.length == 10 ) { //The Phone Number field should contains numbers only var pattern = /^[0-9 -]*$/ ; var flag = pattern.test(trim(varClubCardNumber)); if(flag == false){ return false; }else{ $('#phoneNumber').val(varClubCardNumber); returnVal = true; } } } return returnVal; } HTML <div > <label for="clubCardNumber" >Card or Phone Number:</label> <input id="clubCardNumber" name="clubCardNumber" type="text" placeholder="Card or Phone Number" value="" maxlength="20"/> </div> <input type="hidden" id="phoneNumber" name="phoneNumber" value=""/>

    Read the article

  • Do you use an architectural framework for Flex/AIR development?

    - by Christophe Herreman
    Given that Flex is still a relatively young technology, there are already a bunch of architectural frameworks available for Flex/AIR (and Flash) development, the main ones being Cairngorm and PureMVC. The amount of architectural frameworks is remarkable compared to other technologies. I was wondering how many of you use an architectural framework for Flex development. If so, why, or why not if you don't use any? To share my own experience and point of view: I have used Cairngorm (and ARP for Flash development) on a variety of projects and found that at times, we needed to write extra code just to fit into the framework, which obviously didn't feel right. Although I haven't used PureMVC on many occasions, I have the same gut feeling after looking at the examples applications. Architectural frameworks equal religion in some way. Most followers are convinced that their framework is THE framework and are not open or very skeptical when it comes to using other frameworks. (I also find myself hesitant and skeptical to check out new frameworks, but that is mainly because I would rather wait until the hype is over.) In conclusion, I'm thinking that it is better to have a sound knowledge of patterns and practices that you can apply in your application instead of choosing a framework and sticking to it. There is simply no right or wrong and I don't believe that there will ever be a framework that is considered the holy grail.

    Read the article

  • Copy vector of values to vector of pairs in one line

    - by Kirill V. Lyadvinsky
    I have the following types: struct X { int x; X( int val ) : x(val) {} }; struct X2 { int x2; X2() : x2() {} }; typedef std::pair<X, X2> pair_t; typedef std::vector<pair_t> pairs_vec_t; typedef std::vector<X> X_vec_t; I need to initialize instance of pairs_vec_t with values from X_vec_t. I use the following code and it works as expected: int main() { pairs_vec_t ps; X_vec_t xs; // this is not empty in the production code ps.reserve( xs.size() ); { // I want to change this block to one line code. struct get_pair { pair_t operator()( const X& value ) { return std::make_pair( value, X2() ); } }; std::transform( xs.begin(), xs.end(), back_inserter(ps), get_pair() ); } return 0; } What I'm trying to do is to reduce my copying block to one line with using boost::bind. This code is not working: for_each( xs.begin(), xs.end(), boost::bind( &pairs_vec_t::push_back, ps, boost::bind( &std::make_pair, _1, X2() ) ) ); I know why it is not working, but I want to know how to make it working without declaring extra functions and structs?

    Read the article

  • SQL Server search filter and order by performance issues

    - by John Leidegren
    We have a table value function that returns a list of people you may access, and we have a relation between a search and a person called search result. What we want to do is that wan't to select all people from the search and present them. The query looks like this SELECT qm.PersonID, p.FullName FROM QueryMembership qm INNER JOIN dbo.GetPersonAccess(1) ON GetPersonAccess.PersonID = qm.PersonID INNER JOIN Person p ON p.PersonID = qm.PersonID WHERE qm.QueryID = 1234 There are only 25 rows with QueryID=1234 but there are almost 5 million rows total in the QueryMembership table. The person table has about 40K people in it. QueryID is not a PK, but it is an index. The query plan tells me 97% of the total cost is spent doing "Key Lookup" witht the seek predicate. QueryMembershipID = Scalar Operator (QueryMembership.QueryMembershipID as QM.QueryMembershipID) Why is the PK in there when it's not used in the query at all? and why is it taking so long time? The number of people total 25, with the index, this should be a table scan for all the QueryMembership rows that have QueryID=1234 and then a JOIN on the 25 people that exists in the table value function. Which btw only have to be evaluated once and completes in less than 1 second.

    Read the article

  • How can I check if a user has written his username and password correctly?

    - by Sergio Tapia
    I'm using a Linq-to-SQL class called Scans.dbml. In that class I've dragged a table called Users (username, password, role) onto the graphic area and now I can access User object via a UserRepository class: using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace Scanner.Classes { public class UserRepository { private ScansDataContext db = new ScansDataContext(); public User getUser(string username) { return db.Users.SingleOrDefault(x => x.username == username); } public bool exists(string username) { } } } Now in my Login form, I want to use this Linq-to-SQL goodness to do all the data related activities. UserRepository users = new UserRepository(); private void btnLogin_Click(object sender, EventArgs e) { loginToSystem(); } private void loginToSystem() { if (users.getUser(txtUsername.Text)) { } //If txtUsername exists && User.password == Salt(txtPassword) //then Show.MainForm() with User.accountType in constructor to set permissions. } I need help with verifying that a user exists && that that users.password is equal to SALT(txtpassword.text). Any guidance please?

    Read the article

  • Pronunciation of programming structures (particularly in c#)

    - by Andrzej Nosal
    As a non-English speaking person I often have problems pronouncing certain programming structures and abbreviations. I've been watching some video tutorials and listening to podcasts as well, though I couldn't catch them all. My question is what is the common or correct pronunciation of the following code snippets? Generics, like IEnumerable<int> or in a method void Swap<T>(T lhs, T rhs) Collections indexing and indexer access e.g. garage[i], rectangular arrays myArray[2,1] or jagged[1][2][3] Lambda operator =>, e.g. in a where extension method .Where(animal => animal.Color == Color.Brown) or in an anonymous method () => { return false;} Inheritance class Derived : Base (extends?) class SomeClass : IDisposable (implements?) Arithemtic operators += -= *= /= %= ! Are += and -= pronounced the same for events? Collections initializers new int[] { 4, 5, 8, 9, 12, 13, 16, 17 }; Casting MyEnum foo = (MyEnum)(int)yourFloat; (as?) Nullables DateTime? dt = new DateTime?(); I tagged the question with C# as some of them are specific to C# only.

    Read the article

  • Maximizing the number of true concurrent / parrallel http requests in Silverlight

    - by Clems
    Hi all. I'm using SL 4 beta and my app needs to do a lot of small http requests to the server. I believe that when exceeding the number of allowed concurrent requests, the subsequent requests are put in a queue. I am also aware that SL 4 has both a http browser stack and a http client stack, with both different limit in terms of the number of concurrent requests. Let's say call those limits MAX_BROWSER and MAX_CLIENT. Also I think I read somewhere that the number of concurrent requests is limited per domain, not overall. But I'm sure if this applies to both the http client stack. That means that you CAN have MAX_BROWSER requests to domain1.com AND MAX_BROWSER requests to domain2.com at the same time. And I even believe that sub domains are considered different so you can also have MAX_BROWSER requests to domain1.com AND MAX_BROWSER requests to sub.domain1.com at the same time. I have ownership of the services and domain names so I could easily setup sub domains for my services. Given those considerations I'm trying to optimize the number of concurrent http requests to my server. Here are few questions ? Is is possible to use both stack at the same time ? Is the subdomain/domain story true for both stacks ? None ? If so that would mean that I could potentially have a number of concurrent requests equal to : (MAX_BROWSER + MAX_CLIENT) * NUMBER_OF_DOMAINS which would be fairly good. Is this correct ? I'm kind of sharing my morning thoughts here, hoping somebody has experimented with those things. Thank you.

    Read the article

  • jQuery validation plugin - removing elements

    - by d3020
    I'm using the jQuery validation plugin. On most of my input type... tags I have class='required'. When I submit the page, via JavaScript, the controls on the page that have this class are found. However, there are a handful of checkboxes that I don't need to validate. I've tried removing the class code completely from the input tag, also tried class='cancel', and class='required:false. When doing any of those things though when the form submits it can't find the checkbox control. How do I still keep the ability to do Request.Form and find my checkbox object but at the same time when the form submits don't apply validation to this particular control. Thank you. Edit here. This is what I'm using without the "checked" code and ternary operator. In my input tag I'm calling a function like this... sb.Append(" " + crlf); Inside that function is where I check for the True or False coming back, like this. case "chkFlashedCarton": strResultValue = pst.FlashedCarton.ToString(); if (strResultValue == "True") { strResultValue = " checked"; } break; strResultValue is what is returned back. Does this help to see? Thank you.

    Read the article

  • Query Access and VB.NET

    - by yae
    Hi all: I have 2 tables: "products" and "pieces" PRODUCTS idProd product price PIECES id idProdMain idProdChild quant idProdMain and idProdChild are vinculated with the table: "products". Other considerations is that 1 product can have some pieces and 1 product can be a piece. Price product equal a sum of quantity * price of all their pieces. EXAMPLE: TABLE PRODUCTS (idProd - product - price) 1 - Computer - 300€ 2 - Hard Disk - 100€ 3 - Memory - 50€ 4 - Main Board - 100€ 5 - Software - 50€ 6 - CDroms 100 un. - 30€ TABLE PIECES (id - idProdMain - idProdChild - Quant.) 1 - 1 - 2 - 1 2 - 1 - 3 - 2 3 - 1 - 4 - 1 WHAT I NEED? I need update the price of the main product when the price of the product child (piece) is changed. Following the previous example, if I change the price of this product "memory" (is a piece too) to 60€, then product "Computer" will must change his price to 320€ How I can do it using queries? Already I have tried this to obatin the price of the main product, but not runs. This query not returns any value SELECT Sum(products.price*pieces.quant) AS Expr1 FROM products LEFT JOIN pieces ON (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdChild) AND (products.idProd = pieces.idProdMain) WHERE (((pieces.idProdMain)=5));

    Read the article

  • LINQ to SQL - Why can't you use a WHERE after an ORDER BY?

    - by MCS
    The following code: // select all orders var orders = from o in FoodOrders where o.STATUS = 1 order by o.ORDER_DATE descending select o; // if customer id is specified, only select orders from specific customer if (customerID!=null) { orders = orders.Where(o => customerID.Equals(o.CUSTOMER_ID)); } gives me the following error: Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Linq.IOrderedQueryable'. An explicit conversion exists (are you missing a cast?) I fixed the error by doing the sorting at the end: // select all orders var orders = from o in FoodOrders where o.STATUS = 1 select o; // if customer id is specified, only select orders from specific customer if (customerID!=null) { orders = orders.Where(o => customerID.Equals(o.CUSTOMER_ID)); } // I'm forced to do the ordering here orders = orders.OrderBy(o => o.ORDER_DATE).Reverse(); But I'm wondering why is this limitation in place? What's the reason the API was designed in such a way that you can't add a where constraint after using an order by operator?

    Read the article

  • Entity Framework 4 overwrite Equals and GetHashCode of an own class property

    - by Zhok
    Hi, I’m using Visual Studio 2010 with .NET 4 and Entity Framework 4. I’m working with POCO Classes and not the EF4 Generator. I need to overwrite the Equals() and GetHashCode() Method but that doesn’t really work. Thought it’s something everybody does but I don’t find anything about the problem Online. When I write my own Classes and Equals Method, I use Equals() of property’s, witch need to be loaded by EF to be filled. Like this: public class Item { public virtual int Id { get; set; } public virtual String Name { get; set; } public virtual List<UserItem> UserItems { get; set; } public virtual ItemType ItemType { get; set; } public override bool Equals(object obj) { Item item = obj as Item; if (obj == null) { return false; } return item.Name.Equals(this.Name) && item.ItemType.Equals(this.ItemType); } public override int GetHashCode() { return this.Name.GetHashCode() ^ this.ItemType.GetHashCode(); } } That Code doesn’t work, the problems are in Equals and GetHashCode where I try to get HashCode or Equal from “ItemType” . Every time I get a NullRefernceException if I try to get data by Linq2Entites. A dirty way to fix it, is to capture the NullReferenceException and return false (by Equals) and return base.GetHashCode() (by GethashCode) but I hope there is a better way to fix this problem. I’ve wrote a little test project, with SQL Script for the DB and POCO Domain, EDMX File and Console Test Main Method. You can download it here: Download

    Read the article

  • Having an issue with Nullable MySQL columns in SubSonic 3.0 templates

    - by omegawkd
    Looking at this line in the Settings.ttinclude string CheckNullable(Column col){ string result=""; if(col.IsNullable && col.SysType !="byte[]" && col.SysType !="string") result="?"; return result; } It describes how it determines if the column is nullable based on requirements and returns either "" or "?" to the generated code. Now I'm not too familiar with the ? nullable type operator but from what I can see a cast is required. For instance, if I have a nullable integer MySQL column and I generate the code using the default template files it returns a line similar to this: int? _User_ID; When trying to compile the project I get the error: Cannot implicitly convert type 'int?' to 'int'. An explicit conversion exists (are you missing a cast?) I checked teh Settings files for the other database types and they all seems to have the same routine. So my question is, is this behaviour expected or is this a bug? I need to solve it one way or the other before I can procede. Thanks for your help.

    Read the article

  • Return a list of imported Python modules used in a script?

    - by Jono Bacon
    Hi All, I am writing a program that categorizes a list of Python files by which modules they import. As such I need to scan the collection of .py files ad return a list of which modules they import. As an example, if one of the files I import has the following lines: import os import sys, gtk I would like it to return: ["os", "sys", "gtk"] I played with modulefinder and wrote: from modulefinder import ModuleFinder finder = ModuleFinder() finder.run_script('testscript.py') print 'Loaded modules:' for name, mod in finder.modules.iteritems(): print '%s ' % name, but this returns more than just the modules used in the script. As an example in a script which merely has: import os print os.getenv('USERNAME') The modules returned from the ModuleFinder script return: tokenize heapq __future__ copy_reg sre_compile _collections cStringIO _sre functools random cPickle __builtin__ subprocess cmd gc __main__ operator array select _heapq _threading_local abc _bisect posixpath _random os2emxpath tempfile errno pprint binascii token sre_constants re _abcoll collections ntpath threading opcode _struct _warnings math shlex fcntl genericpath stat string warnings UserDict inspect repr struct sys pwd imp getopt readline copy bdb types strop _functools keyword thread StringIO bisect pickle signal traceback difflib marshal linecache itertools dummy_thread posix doctest unittest time sre_parse os pdb dis ...whereas I just want it to return 'os', as that was the module used in the script. Can anyone help me achieve this?

    Read the article

  • Reading system.net/mailSettings/smtp from Web.config in Medium trust environment

    - by Carson63000
    Hi, I have some inherited code which stores SMTP server, username, password in the system.net/mailSettings/smtp section of the Web.config. It used to read them like so: Configuration c = WebConfigurationManager.OpenWebConfiguration(HttpContext.Current.Request.ApplicationPath); MailSettingsSectionGroup settings = (MailSettingsSectionGroup)c.GetSectionGroup("system.net/mailSettings"); return settings.Smtp.Network.Host; But this was failing when I had to deploy to a medium trust environment. So following the answer from this question, I rewrote it to use GetSection() like so: SmtpSection settings = (SmtpSection)ConfigurationManager.GetSection("system.net/mailSettings/smtp"); return settings.Network.Host; But it's still giving me a SecurityException on Medium trust, with the following message: Request for ConfigurationPermission failed while attempting to access configuration section 'system.net/mailSettings/smtp'. To allow all callers to access the data for this section, set section attribute 'requirePermission' equal 'false' in the configuration file where this section is declared. So I tried this requirePermission attribute, but can't figure out where to put it. If I apply it to the <smtp> node, I get a ConfigurationError: "Unrecognized attribute 'requirePermission'. Note that attribute names are case-sensitive." If I apply it to the <mailSettings> node, I still get the SecurityException. Is there any way to get at this config section programatically under medium trust? Or should I just give up on it and move the setting into <appSettings>?

    Read the article

< Previous Page | 145 146 147 148 149 150 151 152 153 154 155 156  | Next Page >