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  • Looking for design help

    - by jess
    I have this scenario in most of the WindowsForms having grids I have a sequence of code which is similar - AddNewRow(in grid),CreateNewEntity,notifyUser,few other steps Now, I want to use a template kind of pattern.But,my issue is with CreateEntity method since sometimes it is passed a parameter which is different depending on the type of object being created.Should I make createentity accept an "object" type,and cast when the parameter is to be used.What other way can I tackle this design issue? Also,CreateEntity returns the object being created.

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  • g++ linker error--typeinfo, but not vtable

    - by James
    I know the standard answer for a linker error about missing typeinfo usually also involves vtable and some virtual function that I forgot to actually define. I'm fairly certain that's not the situation this time. Here's the error: UI.o: In function boost::shared_ptr<Graphics::Widgets::WidgetSet>::shared_ptr<Graphics::Resource::GroupByState>(boost::shared_ptr<Graphics::Resource::GroupByState> const&, boost::detail::dynamic_cast_tag)': UI.cpp:(.text._ZN5boost10shared_ptrIN8Graphics7Widgets9WidgetSetEEC1INS1_8Resource12GroupByStateEEERKNS0_IT_EENS_6detail16dynamic_cast_tagE[boost::shared_ptr<Graphics::Widgets::WidgetSet>::shared_ptr<Graphics::Resource::GroupByState>(boost::shared_ptr<Graphics::Resource::GroupByState> const&, boost::detail::dynamic_cast_tag)]+0x30): undefined reference totypeinfo for Graphics::Widgets::WidgetSet' Running c++filt on the obnoxious mangled name shows that it actually is looking at .boost::shared_ptr::shared_ptr(boost::shared_ptr const&, boost::detail::dynamic_cast_tag) The inheritance hierarchy looks something like class AbstractGroup { typedef boost::shared_ptr<AbstractGroup> Ptr; ... }; class WidgetSet : public AbstractGroup { typedef boost::shared_ptr<WidgetSet> Ptr; ... }; class GroupByState : public AbstractGroup { ... }; Then there's this: class UI : public GroupByState { ... void LoadWidgets( GroupByState::Ptr resource ); }; Then the original implementation: void UI::LoadWidgets( GroupByState::Ptr resource ) { WidgetSet::Ptr tmp( boost::dynamic_pointer_cast< WidgetSet >(resource) ); if( tmp ) { ... } } Stupid error on my part (trying to cast to a sibling class with a shared parent), even if the error is kind of cryptic. Changing to this: void UI::LoadWidgets( AbstractGroup::Ptr resource ) { WidgetSet::Ptr tmp( boost::dynamic_pointer_cast< WidgetSet >(resource) ); if( tmp ) { ... } } (which I'm fairly sure is what I actually meant to be doing) left me with a very similar error: UI.o: In function boost::shared_ptr<Graphics::Widgets::WidgetSet>::shared_ptr<Graphics::_Drawer::Group>(boost::shared_ptr<Graphics::_Drawer::Group> const&, boost::detail::dynamic_cast_tag)': UI.cpp:(.text._ZN5boost10shared_ptrIN8Graphics7Widgets9WidgetSetEEC1INS1_7_Drawer5GroupEEERKNS0_IT_EENS_6detail16dynamic_cast_tagE[boost::shared_ptr<Graphics::Widgets::WidgetSet>::shared_ptr<Graphics::_Drawer::Group>(boost::shared_ptr<Graphics::_Drawer::Group> const&, boost::detail::dynamic_cast_tag)]+0x30): undefined reference totypeinfo for Graphics::Widgets::WidgetSet' collect2: ld returned 1 exit status dynamic_cast_tag is just an empty struct in boost/shared_ptr.hpp. It's just a guess that boost might have anything at all to do with the error. Passing in a WidgetSet::Ptr totally eliminates the need for a cast, and it builds fine (which is why I think there's more going on than the standard answer for this question). Obviously, I'm trimming away a lot of details that might be important. My next step is to cut it down to the smallest example that fails to build, but I figured I'd try the lazy way out and take a stab on here first. TIA!

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  • Help with data retrieval MACRO

    - by Andrei Ciobanu
    Hello, given the following structure: struct nmslist_elem_s { nmptr data; struct nmslist_elem_s *next; }; typedef struct nmslist_elem_s nmslist_elem; Where: typedef void* nmptr; Is it possible to write a MACRO that retrieves the data from the element and cast it to the right type: MACRO(type, element) that expands to *((type*)element->data). For example for int, i would need something like this: *((int*)(element->data)) .

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  • Converting 'x' value of a CGPoint ivar to NSTimeInterval?

    - by eco_bach
    Hi I have a velocity ivar defined as a CGPoint. I need to somehow extract just the 'x' value of velocity, and then use this to call-send a message to the following method signature -(void) adjustTimer:(NSTimeInterval*)newInterval How do I obtain just the 'x' value of a CGPoint? Do I then need to convert or cast this result before calling my adjustTimer method?

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  • How to find out if an object is of <type> or a decendant of <type>

    - by Vaccano
    I have the following code: foreach (var control in this.Controls) { } I want to do something like control.Hide() in there. But the items in the this.Controls collection are not of type Control (they are Object). I can't seem to remember the safe way to cast this to call hide if it is really of type Control and do nothing otherwise. (I am a transplanted delphi programmer and I keep thinking something like control is Control.)

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  • sql - get the latest date of two columns

    - by stacker
    table1 - date1 datetime not null - date2 nvarchar null I want to get the latest date of this two. select date1, date2, (CASE WHEN date1 > CAST(date2 as DateTime) THEN date1 ELSE date2 END) as DateTime) as LatestDate from table1 please note that date2 can be null. in this case, date1 win.

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  • Parse multiple filters in SQL

    - by Jeff Meatball Yang
    I have a problem parsing a stored procedure parameter in the form: declare @S varchar(100) set @S = '4=2,24=1534' Here's the query: select cast(idx as varchar(100)) 'idx' , value , SUBSTRING(value, 1, charindex(value, '=')+1) 'first' , SUBSTRING(value, charindex(value, '=')+1, LEN(value)-charindex(value, '=')-1) 'second' from Common.SplitToTable(@S, ',') -- returns (idx int, value varchar(max)) where len(value) > 0 But here is the result I get: idx value first second 0 4=2 4 4= 1 24=1534 2 24=153 Here's what I expected: idx value first second 0 4=2 4 2 1 24=1534 2 1534 Help?

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  • Java method: retrieve the inheriting type

    - by DrDro
    I have several classes that extend C and I would need a method that accepts any argument of type C. But in this method I would like to know if I'm dealing with A or B. * public A extends C public B extends C public void goForIt(C c)() If I cast how can I retrieve the type in a clean way (I just read using getClass or instanceof is often not the best way). *Sorry but I can't type closing braces

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  • Why do you have to mark a class with the attribute [serializable] ?

    - by Blankman
    Seeing as you can convert any document to a byte array and save it to disk, and then rebuild the file to its original form (as long as you have meta data for its filename etc.). Why do you have to mark a class with [Serializable] etc? Is that just the same idea, "meta data" type information so when you cast the object to its class things are mapped properly?

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  • Sum function doesn't work :/

    - by StackedCrooked
    A while ago this code seemed to work, but now it doesn't anymore. Is there something wrong with it? user=> (defn sum [a b] (a + b)) #'user/sum user=> (sum 3 4) java.lang.ClassCastException: java.lang.Integer cannot be cast to clojure.lang.IFn (NO_SOURCE_FILE:0) user=> It's probably time to take a break :)

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  • Calculate the SUM of the Column which has Time DataType:

    - by thevan
    I want to calculate the Sum of the Field which has Time DataType. My Table is Below: TableA: TotalTime ------------- 12:18:00 12:18:00 Here I want to sum the two time fields. I tried the below Query SELECT CAST( DATEADD(MS, SUM(DATEDIFF(MS, '00:00:00.000', CONVERT(TIME, TotalTime))), '00:00:00.000' ) AS TOTALTIME) FROM [TableA] But it gives the Output as TOTALTIME ----------------- 00:36:00.0000000 But My Desired Output would be like below: TOTALTIME ----------------- 24:36:00 How to get this Output?

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  • Casting to derived type problem in C++

    - by GONeale
    Hey there everyone, I am quite new to C++, but have worked with C# for years, however it is not helping me here! :) My problem: I have an Actor class which Ball and Peg both derive from on an objective-c iphone game I am working on. As I am testing for collision, I wish to set an instance of Ball and Peg appropriately depending on the actual runtime type of actorA or actorB. My code that tests this as follows: // Actors that collided Actor *actorA = (Actor*) bodyA->GetUserData(); Actor *actorB = (Actor*) bodyB->GetUserData(); Ball* ball; Peg* peg; if (static_cast<Ball*> (actorA)) { // true ball = static_cast<Ball*> (actorA); } else if (static_cast<Ball*> (actorB)) { ball = static_cast<Ball*> (actorB); } if (static_cast<Peg*> (actorA)) { // also true?! peg = static_cast<Peg*> (actorA); } else if (static_cast<Peg*> (actorB)) { peg = static_cast<Peg*> (actorB); } if (peg != NULL) { [peg hitByBall]; } Once ball and peg are set, I then proceed to run the hitByBall method (objective c). Where my problem really lies is in the casting procedurel Ball casts fine from actorA; the first if (static_cast<>) statement steps in and sets the ball pointer appropriately. The second step is to assign the appropriate type to peg. I know peg should be a Peg type and I previously know it will be actorB, however at runtime, detecting the types, I was surprised to find actually the third if (static_cast<>) statement stepped in and set this, this if statement was to check if actorA was a Peg, which we already know actorA is a Ball! Why would it have stepped here and not in the fourth if statement? The only thing I can assume is how casting works differently from c# and that is it finds that actorA which is actually of type Ball derives from Actor and then it found when static_cast<Peg*> (actorA) is performed it found Peg derives from Actor too, so this is a valid test? This could all come down to how I have misunderstood the use of static_cast. How can I achieve what I need? :) I'm really uneasy about what feels to me like a long winded brute-casting attempt here with a ton of ridiculous if statements. I'm sure there is a more elegant way to achieve a simple cast to Peg and cast to Ball dependent on actual type held in actorA and actorB. Hope someone out there can help! :) Thanks a lot.

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  • How to maintain precision using DateTime.Now.Ticks in C#

    - by nmr
    I know that when I use DateTime.Now.Ticks in C# it returns a long value but I need to store it in an int variable and I am confused as to whether or not I can maintain that precision. As of right now I just have a cast int timeStampValue = (int)DateTime.Now.Ticks; Any suggestions or advice on how to maintain the precision, if possible, would be much appreciated.

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  • How to create beautiful Screencasts for your web apps?

    - by Abs
    Hello all, I am trying to create a screen cast for my new web app. I have just come across a great example of a screencast and I am wondering what is used to do this: Click on the video to play on this page. I am impressed with the animation when the mouse is clicked and zooming into images from different angles. Is this done with Actionscript or is there software that will make my life easier to do this? Thanks all for any help

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  • Difference between DirectCast() and CType() in VB.Net

    - by Chapso
    I am an experienced C/C++/C# programmer who has just gotten into VB.NET. I generally use CType (and CInt, CBool, CStr) for casts because it is less characters and was the first way of casting which I was exposed to, but I am aware of DirectCast and TryCast as well. Simply, are there any differences (effect of cast, performance, etc.) between DirectCast and CType? I understand the idea of TryCast.

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  • How to infer the type of a derived class in base class?

    - by enzi
    I want to create a method that allows me to change arbitrary properties of classes that derive from my base class, the result should look like this: SetPropertyValue("size.height", 50); – where size is a property of my derived class and height is a property of size. I'm almost done with my implementation but there's one final obstacle that I want to solve before moving on, to describe this I will first have to explain my implementation a bit: Properties that can be modified are decorated with an attribute There's a method in my base class that searches for all derived classes and their decorated properties For each property I generate a "property modifier", a class that contains 2 delegates: one to set and one to get the value of the property. Property Modifiers are stored in a dictionary, with the name of the property as key In my base class, there is another dictionary that contains all property-modifier-dictionaries, with the Type of the respective class as key. What the SetPropertyValue method does is this: Get the correct property-modifier-dictionary, using the concrete type of the derived class (<- yet to solve) Get the property modifier of the property to change (e.g. of the property size) Use the get or set delegate to modify the property's value Some example code to clarify further: private static Dictionary<RuntimeTypeHandle, object> EditableTypes; //property-modifier-dictionary protected void SetPropertyValue<T>(EditablePropertyMap<T> map, string property, object value) { var property = map[property]; // get the property modifier property.Set((T)this, value); // use the set delegate (encapsulated in a method) } In the above code, T is the Type of the actual (derived) class. I need this type for the get/set delegates. The problem is how to get the EditablePropertyMap<T> when I don't know what T is. My current (ugly) solution is to pass the map in an overriden virtual method in the derived class: public override void SetPropertyValue(string property, object value) { base.SetPropertyValue((EditablePropertyMap<ExampleType>)EditableTypes[typeof(ExampleType)], property, value); } What this does is: get the correct dictionary containing the property modifiers of this class using the class's type, cast it to the appropiate type and pass it to the SetPropertyValue method. I want to get rid of the SetPropertyValue method in my derived class (since there are a lot of derived classes), but don't know yet how to accomplish that. I cannot just make a virtual GetEditablePropertyMap<T> method because I cannot infer a concrete type for T then. I also cannot acces my dictionary directly with a type and retrieve an EditablePropertyMap<T> from it because I cannot cast to it from object in the base class, since again I do not know T. I found some neat tricks to infere types (e.g. by adding a dummy T parameter), but cannot apply them to my specific problem. I'd highly appreciate any suggestions you may have for me.

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  • Char and Chr in Delphi

    - by JamesB
    The difference between Chr and Char when used in converting types is that one is a function and the other is cast So: Char(66) = Chr(66) I don't think there is any performance difference (at least I've never noticed any, one probably calls the other).... I'm fairly sure someone will correct me on this! Which do you use in your code and why?

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  • How to map LINQ EntitySet to List property in property setter?

    - by jlp
    In my model I have these entities: public interface IOrder { string Name {get;set;} List<IProduct> OrderedProducts {get;set;} } public interface IProduct {} In partial class generated by linq-to-sql I map these properties on my entity properties: public partial class Order : IOrder { List<IProduct> OrderedProducts { get { return this.L2SQLProducts.Cast<IProduct>.ToList(); } set { this.L2SQLProducts = ??? } } } How should setter look like?

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  • Checking for a null int value from a Java ResultSet

    - by ian_scho_es
    In Java I'm trying to test for a null value, from a ResultSet, where the column is being cast to a primitive int type. int iVal; ResultSet rs = magicallyAppearingStmt.executeQuery(query); if (rs.next()) { if (rs.getObject("ID_PARENT") != null && !rs.wasNull()) { iVal = rs.getInt("ID_PARENT"); } } From the code fragment above, is there a better way to do this, and I assume that the second wasNull() test is redundant? Educate us, and Thanks

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  • inserting only date in a column in sql server

    - by sam
    hi! Is there a way to insert only date in a datetime column in sql server without the time? for example date (datetime) =============== 12-01-2000 16-02-2000 or i should store this as a varchar and cast it when retriving so that i can convert to whatever form i need.

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  • Mssql varchar to datetime

    - by Dezigo
    I have a field varchar(14) = 20090226115644 I need convert it to - 2009-02-26 11:56:44 (datetime format) My idea. use cast and convert.. but I allways have errors. Conversion failed when converting datetime from character string. I made this, but don`t like it.. SELECT SUBSTRING(move,1,4) + '-' + SUBSTRING(move,5,2) + '-' + SUBSTRING(move,7,2) + ' ' + SUBSTRING(move,9,2) + ':' + SUBSTRING(move,11,2) + ':'+SUBSTRING(move,13,2) as new -- FROM [Test].[dbo].[container_events] where move IS not null Result :2009-02-26 11:56:44

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  • implicit declaration of function 'objc_lookUpClass'

    - by idober
    I am getting this warning for the line code: Class myClass = objc_lookUpClass([_className UTF8String]); I am adding #import <Foundation/NSObjCRuntime.h> #import <objc/objc.h> And it still don't resolve the problem Another warning i get on this line is: "Initialization makes pointer from integer without a cast"

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