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  • C# cast string to enum with enum attribute

    - by rubentjeuh
    Hello, i've got the following question: I've got public enum Als { [StringValue("Beantwoord")] Beantwoord = 0, [StringValue("Niet beantwoord")] NietBeantwoord = 1, [StringValue("Geselecteerd")] Geselecteerd = 2, [StringValue("Niet geselecteerd")] NietGeselecteerd = 3, } with public class StringValueAttribute : System.Attribute { private string _value; public StringValueAttribute(string value) { _value = value; } public string Value { get { return _value; } } } And i would like to put the value from the item I selected of a combobox into a int: int i = ((int)(Als)Enum.Parse(typeof(Als), (string)cboAls.SelectedValue)); //<- WRONG Is this possible, and if so, how? (the stringvalue matches the value selected from the combobox) Thanks

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  • Class Cast Exception

    - by iaagty
    why do i get this exception? Map myHash = null myHash = (HashMap)Collections.synchronizedMap(new HashMap()); If i try to use this hashmap, i get java.lang.ClassCastException

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  • Parallel Assignment operator in Ruby

    - by Bragaadeesh
    Hi, I was going through an example from Programming in Ruby book. This is that example def fib_up_to(max) i1, i2 = 1, 1 # parallel assignment (i1 = 1 and i2 = 1) while i1 <= max yield i1 i1, i2 = i2, i1+i2 end end fib_up_to(100) {|f| print f, " " } The above program simply prints the fibonacci numbers upto 100. Thats fine. My question here is when i replace the parallel assignment with something like this, i1 = i2 i2 = i1+i2 I am not getting the desired output. My question here is, is it advisable to use parallel assignments? (I come from Java background and it feels really wierd to see this type of assignment) One more doubt is : Is parallel assignment an operator?? Thanks

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  • The data types text and nvarchar are incompatible in the equal to operator

    - by metro
    Hi there. this is my code ProductController.cs public ActionResult Details(string id) { product productx = productDB.products.Single(pr => pr.Product1 == id); return View(productx); } Details.aspx <td> <%-- : Html.ActionLink("Edit", "Edit", new { id=item.Id }) % --> <%: Html.ActionLink("Details", "Details", new { id = item.Product1 })%> </td> this is what im using to list some products from a sql database, each product have a link to a Details page to show more informations about it what Im trying is to only put the product label in that link to let it show something like www.mysite.com\products\battery (not the id) I've imagined this should work, but it throw an The data types text and nvarchar are incompatible in the equal to operator. error and neither (pr => pr.Product1.Equals(id)); works the error is clear and Im asking how should I do to make it work this way ? thanks

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  • Cast/initialize submodels of a Backbone Model

    - by nambrot
    I think I have a pretty simple problem that is just pretty difficult to word and therefore hard to find a solution for. Setup: PathCollection is a Backbone.Collection of Paths Path is a Backbone.Model which contains NodeCollection (which is a Backbone.Collection) and EdgeCollection (which is a Backbone.Collection). When I fetch PathCollection paths = new PathCollection() paths.fetch() obviously, Paths get instantiated. However, I'm missing the spot where I can allow a Path to instantiate its submodels from the attribute hashes. I can't really use parse, right? Basically im looking for the entry point for a model when its instantiated and set with attributes. I feel like there must be some convention for it.

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  • What's the purpose of having a separate "operator new[]" ?

    - by sharptooth
    Looks like operator new and operator new[] have exactly the same signature: void* operator new( size_t size ); void* operator new[]( size_t size ); and do exactly the same: either return a pointer to a big enough block of raw (not initialized in any way) memory or throw an exception. Also operator new is called internally when I create an object with new and operator new[] - when I create an array of objects with new[]. Still the above two special functions are called by C++ internally in exactly the same manner and I don't se how the two calls can have different meanings. What's the purpose of having two different functions with exactly the same signatures and exactly the same behavior?

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  • Does replacing statements by expressions using the C++ comma operator could allow more compiler opti

    - by Gabriel Cuvillier
    The C++ comma operator is used to chain individual expressions, yielding the value of the last executed expression as the result. For example the skeleton code (6 statements, 6 expressions): step1; step2; if (condition) step3; return step4; else return step5; May be rewritten to: (1 statement, 6 expressions) return step1, step2, condition? step3, step4 : step5; I noticed that it is not possible to perform step-by-step debugging of such code, as the expression chain seems to be executed as a whole. Does it means that the compiler is able to perform special optimizations which are not possible with the traditional statement approach (specially if the steps are const or inline)? Note: I'm not talking about the coding style merit of that way of expressing sequence of expressions! Just about the possible optimisations allowed by replacing statements by expressions.

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  • regarding like query operator

    - by stackoverflowuser
    Hi For the below data (well..there are many more nodes in the team foundation server table which i need to refer to..below is just a sample) Nodes ------------------------ \node1\node2\node3\ \node1\node2\node5\ \node1\node2\node3\node4 I was wondering if i can apply something like (below query does not give the required results) select * from table_a where nodes like '\node1\node2\%\' to get the below data \node1\node2\node3\ \node1\node2\node5\ and something like (below does not give the required results) select * from table_a where nodes like '\node1\node2\%\%\' to get \node1\node2\node3\ \node1\node2\node5\ \node1\node2\node3\node4 Can the above be done with like operator? Pls. suggest. Thanks

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  • Overriding rubies spaceship operator <=>

    - by ericsteen1
    I am trying to override rubies <= (spaceship) operator to sort apples and oranges so that apples come first sorted by weight, and oranges second, sorted by sweetness. Like so: module Fruity attr_accessor :weight, :sweetness def <=>(other) # use Array#<=> to compare the attributes [self.weight, self.sweetness] <=> [other.weight, other.sweetness] end include Comparable end class Apple include Fruity def initialize(w) self.weight = w end end class Orange include Fruity def initialize(s) self.sweetness = s end end fruits = [Apple.new(2),Orange.new(4),Apple.new(6),Orange.new(9),Apple.new(1),Orange.new(22)] p fruits #should work? p fruits.sort But this does not work, can someone tell what I am doing wrong here, or a better way to do this?

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  • how to cast c++ smart pointer up and down

    - by user217428
    two clients communicate to each other on top of a message layer in the message body, I need include a field pointing to any data type From client A, I send the field as a shared_ptr to the message layer. I define this field as a shared_ptr in the message layer. But how can I convert this field back to shared_ptr in client B? Or should I define shared_ptr in message layer as something else? Thanks

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  • Generic cast type to primitive.

    - by Nix
    Is there a way to do the below? Imagine a generic result wrapper class. Where you have a type and an associated error list. When there is no result to return to the user we will use boolean to indicate success failure. I want to create a constructor that takes in an error list, and if the list is null or count 0, AND the type is a bool/Boolean i want to set it to true.... Seemingly simple, but amazingly not possible. public class Result<T>{ private T valueObject { get;set;} private List<Error> errors{ get;set;} public Result(T valueObj, List<Error> errorList){ this.valueObject = valueObj; this.errors = errorList; } public Result(List<Error> errors) { this.valueObject = default(ReturnType); if (valueObject is Boolean) { //Wont work compile //(valueObject as Boolean) = ((errors == null) || errors.Count == 0); //Compiles but detaches reference //bool temp = ((bool)(valueObject as object)) ; //temp = ((errors == null) || errors.Count == 0); } this.errors = errors; } } } Am I missing something simple? And in general I would prefer to do it without reflection.

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  • USing Min/Max with conditional operator

    - by user638501
    Hello All, I am trying to run a query to find max and min values, and then use a conditional operator. however when I try to run the following query, it gives me error - "misuse of aggregate: min()". My query is: SELECT a.prim_id, min(b.new_len*36) as min_new_len, max(b.new_len*36) as max_new_len FROM tb_first a, tb_second b WHERE a.sec_id = b.sec_id AND min_new_len > 1900 AND max_new_len < 75000 GROUP BY a.prim_id ORDER BY avg(b.new_len*36); Any suggestions ?

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  • Boolean Not operator in VBScript

    - by Lumi
    Consider the following two conditionals (involving bitwise comparisons) in VBScript: If 1 And 3 Then WScript.Echo "yes" Else WScript.Echo "no" If Not(1 And 3) Then WScript.Echo "yes" Else WScript.Echo "no" Prints first yes, then no, right? cscript not.vbs Wrong! It prints yes twice! Wait a second, the Not operator is supposed to perform logical negation on an expression. The logical negation of true is false, as far as I know. Must I conclude that it doesn't live up to that promise? How and why and what is going on here? What is the rationale, if any?

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  • Dynamically create and cast objects at runtime

    - by vaibhav bindroo
    Let's say we have 2 classes A and B public class A{ private int member1; A() { member1 = 10; } public getMember(){ return member1; } } Class B is also on the same lines except that its member variable is named member2 and gets intitialized to say 20 inside the constructor. My Requirement : At runtime , I get a string which contains a className ( could be A or B). I want to dynamically create an object of this class along with invoking the constructor. How can I achieve this . I don't want to use interfaces for common functionality of above classes Morever, later on I set the properties of this raw object using Propery Builder Bean Util class based on a list of columns . Class clazz = Class.forName("className"); Obj obj = clazz.newInstance(); How I can dynamically convert that obj to className object.

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  • Getting a Specified Cast is not valid while importing data from Excel using Linq to SQL

    - by niceoneishere
    This is my second post. After learning from my first post how fantastic is to use Linq to SQL, I wanted to try to import data from a Excel sheet into my SQL database. First My Excel Sheet: it contains 4 columns namely ItemNo ItemSize ItemPrice UnitsSold I have a created a database table with the following fields table name ProductsSold Id int not null identity --with auto increment set to true ItemNo VarChar(10) not null ItemSize VarChar(4) not null ItemPrice Decimal(18,2) not null UnitsSold int not null Now I created a dal.dbml file based on my database and I am trying to import the data from excel sheet to db table using the code below. Everything is happening on click of a button. private const string forecast_query = "SELECT ItemNo, ItemSize, ItemPrice, UnitsSold FROM [Sheet1$]"; protected void btnUpload_Click(object sender, EventArgs e) { var importer = new LinqSqlModelImporter(); if (fileUpload.HasFile) { var uploadFile = new UploadFile(fileUpload.FileName); try { fileUpload.SaveAs(uploadFile.SavePath); if(File.Exists(uploadFile.SavePath)) { importer.SourceConnectionString = uploadFile.GetOleDbConnectionString(); importer.Import(forecast_query); gvDisplay.DataBind(); pnDisplay.Visible = true; } } catch (Exception ex) { Response.Write(ex.Source.ToString()); lblInfo.Text = ex.Message; } finally { uploadFile.DeleteFileNoException(); } } } // Now here is the code for LinqSqlModelImporter public class LinqSqlModelImporter : SqlImporter { public override void Import(string query) { // importing data using oledb command and inserting into db using LINQ to SQL using (var context = new WSDALDataContext()) { using (var myConnection = new OleDbConnection(base.SourceConnectionString)) using (var myCommand = new OleDbCommand(query, myConnection)) { myConnection.Open(); var myReader = myCommand.ExecuteReader(); while (myReader.Read()) { context.ProductsSolds.InsertOnSubmit(new ProductsSold() { ItemNo = myReader.GetString(0), ItemSize = myReader.GetString(1), ItemPrice = myReader.GetDecimal(2), UnitsSold = myReader.GetInt32(3) }); } } context.SubmitChanges(); } } } can someone please tell me where am I making the error or if I am missing something, but this is driving me nuts. When I debugged I am getting this error when casting from a number the value must be a number less than infinity I really appreciate it

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  • C# how to dynamically cast an object?

    - by JL
    I am building a helper object that has a property called Mailer. In reality Mailer can be either a System.Net.Mail.MailMessage or a Mono.System.Net.Mail.MailMessage. So I would preferably only want 1 declaration of mailer. For example I don't want: private Mono.Mailing.MailMessage MonoMessage = new Mono.Mailing.MailMessage(); private System.Net.Mail.MailMessage MailMessage = new System.Net.Mail.MailMessage(); I would prefer object mailer; Then in constructor switch (software) { case EnunInternalMailingSoftware.dotnet: this.mailer = new System.Net.Mail.MailMessage(); break; case EnunInternalMailingSoftware.mono: this.mailer = new Mono.Mailing.MailMessage(); break; } The problem is that mailer has no properties at design time. So I can't compile my code. How can this be fixed, am I taking the right approach. Thanks in advance

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  • C# Cast Class to Overridden Class

    - by Nathan Tornquist
    I have a class Application that I need to override with INotifyPropertyChanged events. I have written the logic to override the original class and ended up creating SuperApplication I am pulling the data from a library though, and cannot change the loading logic. I just need a way to get the data from the original class into my superClass. I've tried things like superClass = (SuperApplication)standardClass; but it hasn't worked. How would I go about doing this? If it helps, this is the code I'm using to override the original class: public class SuperCreditApplication : CreditApplication { public SuperCreditApplicant Applicant { get; set; } public SuperCreditApplicant CoApplicant { get; set; } } public class SuperCreditApplicant : CreditApplicant { public SuperProspect Prospect { get; set; } } public class SuperProspect : Prospect, INotifyPropertyChanged { public State DriverLicenseState { get { return DriverLicenseState; } set { DriverLicenseState = value; OnPropertyChanged("DriverLicenseState"); } } public event PropertyChangedEventHandler PropertyChanged; private void OnPropertyChanged(string propertyName) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } }

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  • field<t> invalid cast

    - by Zwempha
    I'm having problems when using linq on a datatable.asenumerable(). This throws InvalidCastException. DateTime date=r.Field<DateTime>("date"); This works fine. DateTime date = DateTime.Parse(r.Field<string>("date")); What am I missing? Regards Sven

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  • ms-access: missing operator in query expression

    - by every_answer_gets_a_point
    i have this sql statement in access: SELECT * FROM (SELECT [Occurrence Number], [1 0 Preanalytical (Before Testing)], NULL, NULL,NULL FROM [Lab Occurrence Form] WHERE NOT ([1 0 Preanalytical (Before Testing)] IS NULL) UNION SELECT [Occurrence Number], NULL, [2 0 Analytical (Testing Phase)], NULL,NULL FROM [Lab Occurrence Form] WHERE NOT ([2 0 Analytical (Testing Phase)] IS NULL) UNION SELECT [Occurrence Number], NULL, NULL, [3 0 Postanalytical ( After Testing)],NULL FROM [Lab Occurrence Form] WHERE NOT ([3 0 Postanalytical ( After Testing)] IS NULL) UNION SELECT [Occurrence Number], NULL, NULL,NULL [4 0 Other] FROM [Lab Occurrence Form] WHERE NOT ([4 0 Other] IS NULL) ) AS mySubQuery ORDER BY mySubQuery.[Occurrence Number]; everything was fine until i added the last line: SELECT [Occurrence Number], NULL, NULL,NULL [4 0 Other] FROM [Lab Occurrence Form] WHERE NOT ([4 0 Other] IS NULL) i get this error: syntax error (missing operator) in query expression 'NULL [4 0 Other]' anyone have any clues why i am getting this error?

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  • Cast Object to JTable?

    - by Chris
    I am trying to implement a ListSelectionListener for some of my JTables. Simply (at the moment) the ListSelectionListener is supposed to simply return the text of the cell that was selected. My program design has several JTables and I would like to have one ListSelectionListener work for them all. In the valueChanged event of the ListSelectionListener I thought it was possible to do something like: private class SelectionHandler implements ListSelectionListener { public void valueChanged(ListSelectionEvent e) { JTable table = (JTable)e.getSource(); String data = (String) table.getValueAt(table.getSelectedRow(), 0); // Print data } } But when I do this I a ClassCastException error. Is there a way to do something like this? One solution I thought of was to compare the source of the event (e.getSource()) to all my JTables to see if they were equivalent (big if block) and then just calling .getValueAt inside that block but that would making the code in the future difficult if tables were to be added or removed.

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  • Efficiency of PHP arrays cast as objects?

    - by keithjgrant
    From what I understand, PHP objects are generally much faster than arrays. How is that efficiency affected if I'm typecasting to define stdClass objects on the fly: $var = (object)array('one' => 1, 'two' => 2); If the code doing this is deeply-nested, will I be better off explicitly defining $var as an objects instead: $var = new stdClass(); $var->one = 1; $var->two = 2; Is the difference negligible since I'll then be accessing $var as an object from there on, either way?

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  • Why does std::map operator[] create an object if the key doesn't exist?

    - by n1ck
    Hi, I'm pretty sure I already saw this question somewhere (comp.lang.c++? Google doesn't seem to find it there either) but a quick search here doesn't seem to find it so here it is: Why does the std::map operator[] create an object if the key doesn't exist? I don't know but for me this seems counter-intuitive if you compare to most other operator[] (like std::vector) where if you use it you must be sure that the index exists. I'm wondering what's the rationale for implementing this behavior in std::map. Like I said wouldn't it be more intuitive to act more like an index in a vector and crash (well undefined behavior I guess) when accessed with an invalid key? Refining my question after seeing the answers: Ok so far I got a lot of answers saying basically it's cheap so why not or things similar. I totally agree with that but why not use a dedicated function for that (I think one of the comment said that in java there is no operator[] and the function is called put)? My point is why doesn't map operator[] work like a vector? If I use operator[] on an out of range index on a vector I wouldn't like it to insert an element even if it was cheap because that probably mean an error in my code. My point is why isn't it the same thing with map. I mean, for me, using operator[] on a map would mean: i know this key already exist (for whatever reason, i just inserted it, I have redundancy somewhere, whatever). I think it would be more intuitive that way. That said what are the advantage of doing the current behavior with operator[] (and only for that, I agree that a function with the current behavior should be there, just not operator[])? Maybe it give clearer code that way? I don't know. Another answer was that it already existed that way so why not keep it but then, probably when they (the ones before stl) choose to implement it that way they found it provided an advantage or something? So my question is basically: why choose to implement it that way, meaning a somewhat lack of consistency with other operator[]. What benefit do it give? Thanks

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  • Analyzing Python Code: Modulus Operator

    - by Bhubhu Hbuhdbus
    I was looking at some code in Python (I know nothing about Python) and I came across this portion: def do_req(body): global host, req data = "" s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((host, 80)) s.sendall(req % (len(body), body)) tmpdata = s.recv(8192) while len(tmpdata) > 0: data += tmpdata tmpdata = s.recv(8192) s.close() return data This is then called later on with body of huge size, as in over 500,000 bytes. This is sent to an Apache server that has the max request size on the default 8190 bytes. My question is what is happening at the "s.sendall()" part? Obviously the entire body cannot be sent at once and I'm guessing it is reduced by way of the modulus operator. I don't know how it works in Python, though. Can anyone explain? Thanks.

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  • Using reshape + cast to aggregate over multiple columns

    - by DamonJW
    In R, I have a data frame with columns for Seat (factor), Party (factor) and Votes (numeric). I want to create a summary data frame with columns for Seat, Winning party, and Vote share. For example, from the data frame df <- data.frame(party=rep(c('Lab','C','LD'),times=4), votes=c(1,12,2,11,3,10,4,9,5,8,6,15), seat=rep(c('A','B','C','D'),each=3)) I want to get the output seat winner voteshare 1 A C 0.8000000 2 B Lab 0.4583333 3 C C 0.5000000 4 D LD 0.5172414 I can figure out how to achieve this. But I'm sure there must be a better way, probably a cunning one-liner using Hadley Wickham's reshape package. Any suggestions? For what it's worth, my solution uses a function from my package djwutils_2.10.zip and is invoked as follows. But there are all sorts of special cases it doesn't deal with, so I'd rather rely on someone else's code. aggregateList(df, by=list(seat=seat), FUN=list(winner=function(x) x$party[which.max(x$votes)], voteshare=function(x) max(x$votes)/sum(x$votes)))

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