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Search found 49860 results on 1995 pages for 'reference type'.

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  • c++ template: 'is not derived from type'

    - by Allan
    I do not understand why this code is not valid: #include <vector> template <typename T> class A{ public: A() { v.clear(); } std::vector<A<T> *>::const_iterator begin(){ return v.begin(); } private: std::vector<A<T> *> v; }; When compiling it with gcc, it get the following error: test.cpp:8: error: type 'std::vector<A<T>*, std::allocator<A<T>*> >' is not derived from type 'A<T>' test.cpp:8: error: expected ';' before 'begin' test.cpp:12: error: expected `;' before 'private' What is wrong, and how to fix it??

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  • Is it ok to reference .Net assemblies liberally?

    - by panamack
    I'm building a WPF application and working with the MVVM pattern. I have 4 projects in my solution, 3 class libraries, Data, Model and ViewModel and the WPF executable View. Is there anything wrong with the Model referencing WindowsBase so that I can use ObservableCollection<T> for example or can I just make use of what I intuitively feel I need without worrying about the original purposes of the class in the framework e.g. collection databinding.

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  • Direct flow depending on incoming dynamic type

    - by Improfane
    I have a listener class that accepts GUI change events in one method. The incoming event objects have a superclass of a type of GUI Event, the behaviour should depend on the dynamic type of the incoming variable. I wanted to do do lots of methods like: handleGUIEvent(EventChangedX event) handleGUIEvent(EventChangedY event) I am using a single event listener and receiving objects of various types but the behaviour should be different for each. What would you do? I do not want to use a switch statement as this would get unmaintainable.

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  • varchar data type to datetime data type resulted in an out-of-range??

    - by leen3o
    Very weird problem occurred, I have moved a site from one server to another - All is working, but any query involving a date is playing up. I get the following: DELETE FROM MYTABLE WHERE categoryId = -2 AND datecreated < '3/23/2010'; The conversion of a varchar data type to a datetime data type resulted in an out-of-range value Now what's strange is I have changed the LCID to 1033 on the new server as the date is showing as US format and its still throwing an error! I then tried 2057 and again the same error? Made no difference. I'm a little confused, as this is a working site from a server with IIS6 - The locale is 1033 on that server and it works perfectly!! :S I have just tried thrown a Cdate() around the date too and yet again the same error??? Any ideas??

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  • Cannot implicitly convert type 'char*' to 'bool'

    - by neeraj
    i was trying to passing pointer value in the function , i really got stuck here I am a beginner , not getting what value should be put this is programme from the reference of the book "Cracking the coding interview " By Gayle Laakmann McDowell, class Program { unsafe void reverse(char *str) { char* end = str; char tmp; if (str) //Cannot implicitly convert type 'char*' to 'bool' { while(*end) //Cannot implicitly convert type 'char*' to 'bool' { ++end; } --end; while(str<end) { tmp = *str; *str+= *end; *end-= tmp; } } } public static void Main(string[] args) { } }

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  • Using block around a static/singleton resource reference

    - by byte
    This is interesting (to me anyway), and I'd like to see if anyone has a good answer and explanation for this behavior. Say you have a singleton database object (or static database object), and you have it stored in a class Foo. public class Foo { public static SqlConnection DBConn = new SqlConnection(ConfigurationManager.ConnectionStrings["BAR"].ConnectionString); } Then, lets say that you are cognizant of the usefulness of calling and disposing your connection (pretend for this example that its a one-time use for purposes of illustration). So you decide to use a 'using' block to take care of the Dispose() call. using (SqlConnection conn = Foo.DBConn) { conn.Open(); using (SqlCommand cmd = new SqlCommand()) { cmd.Connection = conn; cmd.CommandType = System.Data.CommandType.StoredProcedure; cmd.CommandText = "SP_YOUR_PROC"; cmd.ExecuteNonQuery(); } conn.Close(); } This fails, with an error stating that the "ConnectionString property is not initialized". It's not an issue with pulling the connection string from the app.config/web.config. When you investigate in a debug session you see that Foo.DBConn is not null, but contains empty properties. Why is this?

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  • Is Android reference at android.com good enough

    - by the100rabh
    Hi, I am a C++ developer, but have a fair idea of Java as I learnt it in college 5years ago. I have been trying to learn programming for android. But instead of rushing to buy books, I have tried to read through the Android Dev Guide and learn from there making use of the sample applications. Thats besides SO ofcourse. I am trying to make some apps based on ideas I have. So my question is, Is it suitable or possible to learn android programming this way. Or is there something that I will be missing in all this.

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  • C# - What is root reference ?

    - by DotNetGuy
    class GCTest { static Object r1; static void Main() { r1 = new Object(); Object r2 = new Object(); Object r3 = new Object(); System.GC.Collect(); // what can be reclaimed here ? r1 = null; r3.ToString(); System.GC.Collect(); // what can be reclaimed here ? } } // code from - DonBox's Essential .Net

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  • Backbone: Easiest way to maintain reference to 'this' for a Model inside callbacks

    - by Garrett
    var JavascriptHelper = Backbone.Model.extend("JavascriptHelper", {}, // never initialized as an instance { myFn: function() { $('.selector').live('click', function() { this.anotherFn(); // FAIL! }); }, anotherFn: function() { alert('This is never called from myFn()'); } } ); The usual _.bindAll(this, ...) approach won't work here because I am never initializing this model as an instance. Any ideas? Thanks.

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  • Linq to SQl Stored Procedure Problem( it can't figure out the return type)

    - by chobo2
    Hi I have this SP USE [Test] GO SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO CREATE PROCEDURE [dbo].[UsersInsert](@UpdatedProdData XML) AS INSERT INTO dbo.UserTable(UserId,UserName,LicenseId,Password,PasswordSalt,Email,IsApproved,IsLockedOut,CreateDate, LastLoginDate,LastLockOutDate,FailedPasswordAttempts,RoleId) SELECT @UpdatedProdData.value('(/ArrayOfUsers/Users/UserId)[1]', 'uniqueidentifier'), @UpdatedProdData.value('(/ArrayOfUsers/Users/UserName)[1]', 'varchar(20)'), @UpdatedProdData.value('(/ArrayOfUsers/Users/LicenseId)[1]', 'varchar(50)'), @UpdatedProdData.value('(/ArrayOfUsers/Users/Password)[1]', 'varchar(128)'), @UpdatedProdData.value('(/ArrayOfUsers/Users/PasswordSalt)[1]', 'varchar(128)'), @UpdatedProdData.value('(/ArrayOfUsers/Users/Email)[1]', 'varchar(50)'), @UpdatedProdData.value('(/ArrayOfUsers/Users/IsApproved)[1]', 'bit'), @UpdatedProdData.value('(/ArrayOfUsers/Users/IsLockedOut)[1]', 'bit'), @UpdatedProdData.value('(/ArrayOfUsers/Users/CreateDate)[1]', 'datetime'), @UpdatedProdData.value('(/ArrayOfUsers/Users/LastLoginDate)[1]', 'datetime'), @UpdatedProdData.value('(/ArrayOfUsers/Users/LastLockOutDate)[1]', 'datetime'), @UpdatedProdData.value('(/ArrayOfUsers/Users/FailedPasswordAttempts)[1]', 'int'), @UpdatedProdData.value('(/ArrayOfUsers/Users/RoleId)[1]', 'int') Now this SP creates just fine. It's when I go to VS2010 and try to drag this SP in my method panel of my linq to sql file in design view. It tells me that it can't figure out the return type. I try to go to the properties but it does not have "none" as a choice and I can't type it in. It should be "none" so how do I set it to "none"?

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  • Is there a definitive list of uri patterns for use in android apps made by google?

    - by The Trav
    Apart from http://developer.android.com/guide/appendix/g-app-intents.html (which is quite good but fairly limited in the number of apps/uri's it covers) I've been unable to find a decent reference source for looking up URI's to use when integrating with google apps. I'm currently working on triggering the "add new contact" UI, and have found that the tel: uri pattern seems to work, but what if I only have a name and an email? I wouldn't have expected I'd need to rely on sample code / trial and error, but I really can't see anywhere where the intent/URI interface is supposed to be documented in android apps. Does such a standard exist? Is there some quasi standard / user database that I can consult? On a platform with such a good inter-interoperability architecture it just seems like something so useful I can't believe it's not there

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  • Does "Value Restriction" practically mean that there is no higher order functional programming?

    - by Sadache
    Does "Value Restriction" practically mean that there is no higher order functional programming? I have a problem that each time I try to do a bit of HOP I get caught by a VR error. Example: let simple (s:string)= fun rq->1 let oops= simple "" type 'a SimpleType= F of (int ->'a-> 'a) let get a = F(fun req -> id) let oops2= get "" and I would like to know whether it is a problem of a prticular implementation of VR or it is a general problem that has no solution in a mutable type-infered language that doesn't include mutation in the type system.

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  • Redeclaration of parameters

    - by Scott
    While looking through the Selenium source code I noticed the following in the PageFactory: public static <T> T initElements(WebDriver driver, Class<T> pageClassToProxy) { T page = instantiatePage(driver, pageClassToProxy); initElements(driver, page); return page; } public static void initElements(WebDriver driver, Object page) { final WebDriver driverRef = driver; initElements(new DefaultElementLocatorFactory(driverRef), page); } What is the benefit of having the following line? final WebDriver driverRef = driver; Wouldn't it have made sense to just make the parameter final, and then passing that along to the next method without declaring the new reference?

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  • Is there a way to localize input type="date" in HTML5

    - by lambacck
    I know that at the time of this writing only Opera supports a browser UI for <input type="date" name="mydate"> and maybe my attempts to localize this field have been met with frustration because niceties like localization have not yet been included in their implementation, but I don't even see mention of it in the HTML5 spec. Is there a way that localization should be specified? Should I do lang="fr" on a parent element? Some notes on the implementation of the site in question: Localization (language) is explicitly picked by the user because they are managing data in multiple languages and it is not reasonable to expect that the user's browser chrome is in the language being viewed or that the browser is providing desired language request headers. I want to be sure that if the page is rendered in French that the date picker provided by browser chrome shows options that make sense for French language. The plan is to fall back to jQueryUI for browsers that do not support type="date", I will use the detection mechanism provided in Dive into HTML 5

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  • Iterating over member typed collection fails when using untyped reference to generic object

    - by Alexander Pavlov
    Could someone clarify why iterate1() is not accepted by compiler (Java 1.6)? I do not see why iterate2() and iterate3() are much better. This paragraph is added to avoid silly "Your post does not have much context to explain the code sections; please explain your scenario more clearly." protection. import java.util.Collection; import java.util.HashSet; public class Test<T> { public Collection<String> getCollection() { return new HashSet<String>(); } public void iterate1(Test test) { for (String s : test.getCollection()) { // ... } } public void iterate2(Test test) { Collection<String> c = test.getCollection(); for (String s : c) { // ... } } public void iterate3(Test<?> test) { for (String s : test.getCollection()) { // ... } } } Compiler output: $ javac Test.java Test.java:11: incompatible types found : java.lang.Object required: java.lang.String for (String s : test.getCollection()) { ^ Note: Test.java uses unchecked or unsafe operations. Note: Recompile with -Xlint:unchecked for details. 1 error

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  • Using module include in OCaml

    - by Geoff
    In OCaml 3.11, I want to "extend" an existing module using the include directive, like so: module MyString = struct include String let trim s = ... end No problem. But now I want to expose this module's type explicitly (i.e. in a .mli file). I want something like this: module MyString : sig include String val trim : string -> string end But the include syntax is not correct because String refers to a module, not a module type (and the compiler does indeed barf). How can I refer to the module type for String here (without having write it out explicitly in a sig expression)? Thanks!

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  • Using NSArray for C-type int comparisons

    - by Andrew Barinov
    I would like to iterate through an NSArray of ints and compare each one to a specific int. All ints are C type ints. The code I am using is as follows: -(int)ladderCalc: (NSArray*)amounts: (int)amount { int result; for (NSUInteger i=0; i< [amounts count]; i++) { if (amount < [amounts objectAtIndex:i]); { // do something } // do something } } However I get an error when comparing the int amount to the result of [amounts objectAtIndex:i] because you cannot compare id to int. Why is the id involved in this case? Shouldn't objectAtIndex just return the object at the index specified? Is it possible to cast the object returned to an C int and then do the comparison? Or should I just dispense with NSArray and do this type of thing in C?

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  • Null reference for first memory address between 0 - 65535

    - by Terry
    I would like to understand a bit more about memory and I was unable to find it from Google, please forgive me if this is silly question. How come the following code, accessing memory address 0(and up to 65535) in C# would throw NullReferenceException byte* pointer = (byte*)0; byte test = *pointer; Thanks a lot in advance!

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  • Django admin, filter objects by ManyToMany reference

    - by Nick Z
    Hello! There's photologue application, simple photo gallery for django, implementing Photo and Gallery objects. Gallery object has ManyToMany field, which references Photo objects. I need to be able to get list of all Photos for a given Gallery. Is it possible to add Gallery filter to Photo's admin page? If it's possible, how to do it best?

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  • GIT core.editor setup on windows along w application PATH reference

    - by delinquentme
    Hey all so i wehnt ahead and opened up my .gitconfig file and manually input the [core] editor = 'C:/Program Files/Notepad++/notepad++.exe' which would allow me to execute command: (im trying to setup my .gitignore list) "C:/Program Files/Notepad++/notepad++.exe" .gitignore im JUSt not interested in typing this out every time that i need to make a file SO ive heard something about editing PATH to allow me to replace the above with something like: npp .gitignore any help would be aprpeciated!

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  • mysql reference result from subquery

    - by iamrohitbanga
    this is what i am doing update t1 set x=a,y=b where a and b are obtained from (select query here) i know the select query the select query returns multiple results which are the same when i use group by or distinct query execution slows down considerably a and b are forward references so mysql reports an error i want to set a equal to the value obtained in the first row and b equal to the value obtained in the first row for the respective columns, to avoid group by. i don't know how to refer to the first result from the select query. how can i achieve all this?

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  • Referencing text input fields in CKEditor dialogs

    - by rt-uk
    Hi, I've been playing around with this for a couple of weeks now with no success... In a CKEditor dialog, text input fields are renamed with a unique number - e.g. id: 'txtUrl' will become something like id='27_textinput'. How do I reference this? // I feel it should be something like: var myfield = CKEDITOR.instances.myElement.document.$.body.getId('txtUrl'); // or maybe: var myfield = CKEDITOR.dialog.getContentElement('info','txtUrl'); // and then: myfield.value = 'myvalue'; But these don't work. Please help! Thanks in advance, R

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