Search Results

Search found 13518 results on 541 pages for 'graphical interface'.

Page 3/541 | < Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >

• Objective-C Interface Builder don't see renamed class

  - by Jerve

  Hi, I've renamed a UITableViewController class in Xcode, which was used as a parent class in a XIB. The Interface Builder still uses the old name for that class and it compiles and works fine. Interface Builder doesn't see the new name of the class and when I try to type in manually, it compiles and gives me an exception at the runtime: "Unknown class ... in Interface Builder file." Is there a way to update the class name in the Interface Builder? Thanks

  Read the article

• Define interface for loading custom UserControls through reflection

  - by Tim

  I'm loading custom user controls into my form using reflection. I would like all my user controls to have a "Start" and "End" method so they should all be like: public interface IStartEnd { void Start(); void End(); } public class AnotherControl : UserControl, IStartEnd { public void Start() { } public void End() { } } I would like an interface to load through reflection, but the following obviously wont work as an interface cannot inherit a class: public interface IMyUserControls : UserControl, IInit, IDispose { }

  Read the article

• Getting the constructor of an Interface Type through reflection, is there a better approach than loo

  - by Will Marcouiller

  I have written a generic type: IDirectorySource<T> where T : IDirectoryEntry, which I'm using to manage Active Directory entries through my interfaces objects: IGroup, IOrganizationalUnit, IUser. So that I can write the following: IDirectorySource<IGroup> groups = new DirectorySource<IGroup>(); // Where IGroup implements `IDirectoryEntry`, of course.` foreach (IGroup g in groups.ToList()) { listView1.Items.Add(g.Name).SubItems.Add(g.Description); } From the IDirectorySource<T>.ToList() methods, I use reflection to find out the appropriate constructor for the type parameter T. However, since T is given an interface type, it cannot find any constructor at all! Of course, I have an internal class Group : IGroup which implements the IGroup interface. No matter how hard I have tried, I can't figure out how to get the constructor out of my interface through my implementing class. [DirectorySchemaAttribute("group")] public interface IGroup { } internal class Group : IGroup { internal Group(DirectoryEntry entry) { NativeEntry = entry; Domain = NativeEntry.Path; } // Implementing IGroup interface... } Within the ToList() method of my IDirectorySource<T> interface implementation, I look for the constructor of T as follows: internal class DirectorySource<T> : IDirectorySource<T> { // Implementing properties... // Methods implementations... public IList<T> ToList() { Type t = typeof(T) // Let's assume we're always working with the IGroup interface as T here to keep it simple. // So, my `DirectorySchema` property is already set to "group". // My `DirectorySearcher` is already instantiated here, as I do it within the DirectorySource<T> constructor. Searcher.Filter = string.Format("(&(objectClass={0}))", DirectorySchema) ConstructorInfo ctor = null; ParameterInfo[] params = null; // This is where I get stuck for now... Please see the helper method. GetConstructor(out ctor, out params, new Type() { DirectoryEntry }); SearchResultCollection results = null; try { results = Searcher.FindAll(); } catch (DirectoryServicesCOMException ex) { // Handling exception here... } foreach (SearchResult entry in results) entities.Add(ctor.Invoke(new object() { entry.GetDirectoryEntry() })); return entities; } } private void GetConstructor(out ConstructorInfo constructor, out ParameterInfo[] parameters, Type paramsTypes) { Type t = typeof(T); ConstructorInfo[] ctors = t.GetConstructors(BindingFlags.CreateInstance | BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.InvokeMethod); bool found = true; foreach (ContructorInfo c in ctors) { parameters = c.GetParameters(); if (parameters.GetLength(0) == paramsTypes.GetLength(0)) { for (int index = 0; index < parameters.GetLength(0); ++index) { if (!(parameters[index].GetType() is paramsTypes[index].GetType())) found = false; } if (found) { constructor = c; return; } } } // Processing constructor not found message here... } My problem is that T will always be an interface, so it never finds a constructor. Is there a better way than looping through all of my assembly types for implementations of my interface? I don't care about rewriting a piece of my code, I want to do it right on the first place so that I won't need to come back again and again and again. EDIT #1 Following Sam's advice, I will for now go with the IName and Name convention. However, is it me or there's some way to improve my code? Thanks! =)

  Read the article

• Java Interface Usage Guidelines -- Are getters and setters in an interface bad?

  - by user68759

  What do people think of the best guidelines to use in an interface? What should and shouldn't go into an interface? I've heard people say that, as a general rule, an interface must only define behavior and not state. Does this mean that an interface shouldn't contain getters and setters? My opinion: Maybe not so for setters, but sometimes I think that getters are valid to be placed in an interface. This is merely to enforce the implementation classes to implement those getters and so to indicate that the clients are able to call those getters to check on something, for example.

  Read the article

• Java Interface Reflection Alternatives

  - by Phaedrus

  I am developing an application that makes use of the Java Interface as more than a Java interface, i.e., During runtime, the user should be able to list the available methods within the interface class, which may be anything: private Class<? extends BaseInterface> interfaceClass. At runtime, I would like to enum the available methods, and then based on what the user chooses, invoke some method. My question is: Does the Java "Interface" architecture provide any method for me to peek and invoke methods without using the Reflection API? I wish there were something like this (Maybe there is): private Interface<? extends BaseInterface> interfaceAPI; public void someMethod(){ interfaceAPI.listMethods(); interfaceAPI.getAnnotations(); } Maybe there is some way to use Type Generics to accomplish what I want? Thanks, Phaedrus

  Read the article

• How do I install Postgres Graphical Installer?

  - by Tusar Das

  I am a newbie in using Ubuntu (more precisely never used linux except the production deployment ). Now I choose to hold a grip on the system and intalled a latest 11.10 Ubuntu in my 32 bit Intel** desktop. In this machine **I have a 'administrator' user 'tusar'. I want to install the PostgreSQL graphical version so downloaded this file postgresql-8.4.9-1-linux.bin from here Now If run the file with ./filename command (refuses if I am not root), it opens up the graphical interface and completes the installation (creates user postgres and ask for password, wont complete if I dont give valid password). I checked with /etc/inint.d/postgresql-8.4 status , that postgres is running. But the problem is I am unable to open the GUI (I installed it in /opt/Postgresql ), its telling permission denied even if I am logged in as 'tusar'. Then I tried using the su postgres command and it directly changed the user without password. Now if I run the psql , createdb , its prompting me to install the postgres-client-package but this utilies are already installed and I can view them in my /opt/Postgresql/8.4/bin folder. I can run query through my JDBC utility programs but unable to use neither terminal nor the graphical interface (although I can see pgAdmin3 is there ). Urgent help needed. I have used this guide for the installation.

  Read the article

• User Interface Annoyances

  - by Jim McKeeth

  I am looking for some of the most annoying user interface features that are common and keep being repeated. The first one that comes to mind is the modal pop up message box that developers like to use to let you know you did something right, but gets frustrating the 1000th time you have to close it. I would rather see the annoyances that are common in many applications instead of the one really odd ones that are only in one or two applications. Please: One per answer.

  Read the article

• Question about the Cloneable interface and the exception that should be thrown

  - by Nazgulled

  Hi, The Java documentation says: A class implements the Cloneable interface to indicate to the Object.clone() method that it is legal for that method to make a field-for-field copy of instances of that class. Invoking Object's clone method on an instance that does not implement the Cloneable interface results in the exception CloneNotSupportedException being thrown. By convention, classes that implement this interface should override Object.clone (which is protected) with a public method. See Object.clone() for details on overriding this method. Note that this interface does not contain the clone method. Therefore, it is not possible to clone an object merely by virtue of the fact that it implements this interface. Even if the clone method is invoked reflectively, there is no guarantee that it will succeed. And I have this UserProfile class: public class UserProfile implements Cloneable { private String name; private int ssn; private String address; public UserProfile(String name, int ssn, String address) { this.name = name; this.ssn = ssn; this.address = address; } public UserProfile(UserProfile user) { this.name = user.getName(); this.ssn = user.getSSN(); this.address = user.getAddress(); } // get methods here... @Override public UserProfile clone() { return new UserProfile(this); } } And for testing porpuses, I do this in main(): UserProfile up1 = new UserProfile("User", 123, "Street"); UserProfile up2 = up1.clone(); So far, no problems compiling/running. Now, per my understanding of the documentation, removing implements Cloneable from the UserProfile class should throw an exception in up1.clone() call, but it doesn't. I've read around here that the Cloneable interface is broken but I don't really know what that means. Am I missing something?

  Read the article

• Seeking suggestions on redesigning the interface

  - by ratkok

  As a part of maintaining large piece of legacy code, we need to change part of the design mainly to make it more testable (unit testing). One of the issues we need to resolve is the existing interface between components. The interface between two components is a class that contains static methods only. Simplified example: class ABInterface { static methodA(); static methodB(); ... static methodZ(); }; The interface is used by component A so that different methods can use ABInterface::methodA() in order to prepare some input data and then invoke appropriate functions within component B. Now we are trying to redesign this interface for various reasons: Extending our unit test coverage - we need to resolve this dependency between the components and stubs/mocks are to be introduced The interface between these components diverged from the original design (ie. a lots of newer functions, used for the inter-component i/f are created outside this interface class). The code is old, changed a lot over the time and needs to be refactored. The change should not be disruptive for the rest of the system. We try to limit leaving many test-required artifacts in the production code. Performance is very important and should be no (or very minimal) degradation after the redesign. Code is OO in C++. I am looking for some ideas what approach to take. Any suggestions on how to do this efficiently?

  Read the article

• Implementation question involving implementing an interface

  - by Vivin Paliath

  I'm writing a set of collection classes for different types of Trees. I'm doing this as a learning exercise and I'm also hoping it turns out to be something useful. I really want to do this the right way and so I've been reading Effective Java and I've also been looking at the way Joshua Bloch implemented the collection classes by looking at the source. I seem to have a fair idea of what is being done, but I still have a few things to sort out. I have a Node<T> interface and an AbstractNode<T> class that implements the Node interface. I then created a GenericNode<T> (a node that can have 0 to n children, and that is part of an n-ary tree) class that extends AbstractNode<T> and implements Node<T>. This part was easy. Next, I created a Tree<T> interface and an AbstractTree<T> class that implements the Tree<T> interface. After that, I started writing a GenericTree<T> class that extends AbstractTree<T> and implements Tree<T>. This is where I started having problems. As far as the design is concerned, a GenericTree<T> can only consist of nodes of type GenericTreeNode<T>. This includes the root. In my Tree<T> interface I have: public interface Tree<T> { void setRoot(Node<T> root); Node<T> getRoot(); List<Node<T>> postOrder(); ... rest omitted ... } And, AbstractTree<T> implements this interface: public abstract class AbstractTree<T> implements Tree<T> { protected Node<T> root; protected AbstractTree() { } protected AbstractTree(Node<T> root) { this.root = root; } public void setRoot(Node<T> root) { this.root = root; } public Node<T> getRoot() { return this.root; } ... rest omitted ... } In GenericTree<T>, I can have: public GenericTree(Node<T> root) { super(root); } But what this means is that you can create a generic tree using any subtype of Node<T>. You can also set the root of a tree to any subtype of Node<T>. I want to be able to restrict the type of the node to the type of the tree that it can represent. To fix this, I can do this: public GenericTree(GenericNode<T> root) { super(root); } However, setRoot still accepts a parameter of type Node<T>. Which means a user can still create a tree with the wrong type of root node. How do I enforce this constraint? The only way I can think of doing is either: Do an instanceof which limits the check to runtime. I'm not a huge fan of this. Remove setRoot from the interface and have the base class implement this method. This means that it is not part of the contract and anyone who wants to make a new type of tree needs to remember to implement this method. Is there a better way? The second question I have concerns the return type of postOrder which is List<Node<T>>. This means that if a user is operating on a GenericTree<T> object and calls postOrder, he or she receives a list that consists of Node<T> objects. This means when iterating through (using a foreach construct) they would have perform an explicit cast to GenericNode<T> if they want to use methods that are only defined in that class. I don't like having to place this burden on the user. What are my options in this case? I can only think of removing the method from the interface and have the subclass implement this method making sure that it returns a list of appropriate subtype of Node<T>. However, this once again removes it from the contract and it's anyone who wants to create a new type of tree has to remember to implement this method. Is there a better way?

  Read the article

• Algorithm to distribute objects in a box (like InDesign, Illustrator, Draw!)

  - by Rafael Almeida

  I have a set of rectangles with their corresponding positions and a big rectangle which serves as the 'bounding box' for these rectangles. I would like to know of an algorithm that would 'distribute the free space' evenly among the rectangles. Some of you may be familiar with the Distribute Spacing option in Adobe InDesign and similar layout-oriented apps. That would be what I'm looking for. I did try looking it up, but I'm not familiar with 'graphical' algorithms terminology and trying only terms relating to 'distribute' mainly yields results about Distributed Computing. So, even the names of the algorithms or better terms to look up would be a big help. Finally, the algorithm doesn't need to be rigorously the same as InDesign's one: pretty much any algorithm that 'distributes' objects inside a region will work fine. In fact, since I'm striving for visual appeal mainly, the more suggestions the better. =D

  Read the article

• How to make computer interface with circuit

  - by light.hammer

  I understand that I can build a circuit that will do whatever I like (ex: a simple circuit that will turn on a motor to open the blinds or something), and I can write a program that will automate my computer/mac however I like (ex: open this program at this time, or with this input and create a new file, ect). My question is, how can I interface the two? Is there an easy DIY or cheap commercial (or not cheap but functional) USB plug that will turn on/off from computer commands? I'm basically looking for some sort of on/off switch I can script/applescript. How would you even approach this problem, would I have to write my own driver some where along the way?

  Read the article

• In Enterprise Architect I modified an interface, how to update the realizing classes?

  - by Timo

  I've created an interface in a class model. This interface has two methods, A and B and method A takes an argument (a) and method B does not take an argument (yet). Additionally I've created a class that implements this interface, overriding both methods. After a discussing the model method B now should also take a parameter (b), so I modified the interface to reflect this change. However the class realizing this interface is not updated automatically. For one class it's possible to add the method by re-creating the link between the interface, specify the which method should be implemented and deleting this link again. Then the OLD method signature has to be removed as well. This is a lot of work if there is more then one class implementing the modified interface, not to mention error-prone. Does anybody know how to make an entire class model update this type of dependency?

  Read the article

• Frustration with superuser.com user interface (please migrate this to "meta")

  - by Randolf Richardson

  Can someone please migrate this question to "meta" for me? I'm unable to post there while I wait for OpenID to fix my password problems. Thanks. I'm having problems with superuser.com's interface -- when I provide an answer to a question, sometimes the buttons get locked and then I find out that the question was migrated. Usually I can go back and copy-and-paste my answer at whatever site it goes to, but on occasion my answer is lost and I have to re-type it. This is very time-consuming, and makes it quite frustrating to use the system. In addition, I find that I'm wasting a lot of time dealing with having to re-register on the other sites. My suggestion is to not de-activate the "Submit answer" button but to just forward that along to the migrated site automatically, thus ensuring that answers that people put a lot of effort into don't get lost. Thanks in advance.

  Read the article

• Pause Nagios reloading in web interface

  - by 2rec

  Is there any option how could I turn off reloading of web page in Nagios web interface? Many times I checked many services and I needed the webpage to stay static and don't reload. One solution come to my mind - turn off the whole reloading for a while. Problem is that other people are using it too and they may want it at the time I don't want it. If anybody know about any kind of workaround or solution, please don't hesitate to write an answer. ;-) EDIT (+ reaction to the first answer): Maybe there could be a better way how to do it instead of modyfying nagios core. Interesting is, that I tried to disable javascript, it refreshed. I tried to disable http refreshing, it refreshed anyway. Has anybody know how and where is the refresh implemented?

  Read the article

• Programmatically implementing an interface that combines some instances of the same interface in var

  - by namin

  What is the best way to implement an interface that combines some instances of the same interface in various specified ways? I need to do this for multiple interfaces and I want to minimize the boilerplate and still achieve good efficiency, because I need this for a critical production system. Here is a sketch of the problem. Abstractly, I have a generic combiner class which takes the instances and specify the various combinators: class Combiner<I> { I[] instances; <T> T combineSomeWay(InstanceMethod<I,T> method) { // ... method.call(instances[i]) ... combined in some way ... } // more combinators } Now, let's say I want to implement the following interface among many others: Interface Foo { String bar(int baz); } I want to end up with code like this: class FooCombiner implements Foo { Combiner<Foo> combiner; @Override public String bar(final int baz) { return combiner.combineSomeWay(new InstanceMethod<Foo, String> { @Override public call(Foo instance) { return instance.bar(baz); } }); } } Now, this can quickly get long and winded if the interfaces have lots of methods. I know I could use a dynamic proxy from the Java reflection API to implement such interfaces, but method access via reflection is hundred times slower. So what are the alternatives to boilerplate and reflection in this case?

  Read the article

• How to fix error - "@interface interfaceName : someEnumeration" gives error "cannot find interface '

  - by Paul V

  How can I solve "cannot find interface declaration 'someEnumeration', superclass of 'interfaceName'" error? What steps will reproduce the problem? Compiling Wsdl2ObjC Targeting groupwise.wsdl file Fixing non-valid file names of output csource code like ".h" + ".m" and objects inside source files Moving up one of the @interface BEFORE it was used futher in code! What is the expected output? Something working What do you see instead? 33 errors. "Inherited" from only 3 similar Inheritances of a typedef enum object by a class. All errors are typical: typedef enum types_StatusTrackingOptions { types_StatusTrackingOptions_none = 0, types_StatusTrackingOptions_None, types_StatusTrackingOptions_Delivered, types_StatusTrackingOptions_DeliveredAndOpened, types_StatusTrackingOptions_All, } types_StatusTrackingOptions; types_StatusTrackingOptions types_StatusTrackingOptions_enumFromString(NSString *string); NSString * types_StatusTrackingOptions_stringFromEnum(types_StatusTrackingOptions enumValue); @interface types_StatusTracking : types_StatusTrackingOptions { ... and here I'm having error "cannot find interface declaration for 'types_StatusTrackingOptions', superclass of 'types_StatusTracking'". What version of the product are you using? On what operating system? Wsdl2ObjC - rev 168, OS - Mac OS X 10.6.2, iPhone SDK - 3.2, Simulator - v. 3.1.2 - 3.1.3, wsdl - for GroupWise v.8, NDK released 2008-12-23, wsdl and xsd files are attached. P.S. GroupWise.wsdl + .xsd files could be downloaded from http://code.google.com/p/wsdl2objc/issues/detail?id=99

  Read the article

• Graphical Email-client with Sent-emails -directory?

  - by hhh

  I asked this question here but without any answer. So I am now looking something to replace Evolution -email-client. So does there exist a graphical Email-client with Sent-directory? Or is it specified system-wide? P.s. I know Mutt has this feature but I cannot understand how graphical Email -clients work in this, perhaps I cannot just find this feature -- I don't know. Basically, I just want to see emails that I have sent. My email -client has many emails connected. Perhaps related I am also interested to have this kind of feature in Android -device, more here. Where do Sent -emails go in Evolution?

  Read the article

• '6' key stuck when outside the graphical interface

  - by Felipe Jacob

  A strange thing has been happening since I installed Ubuntu. Whenever I'm not on the graphical interface, that is, if I do ctrl+alt+f2, or while the system is shutting down, or when I try to reset my password accessing root on security mode, the '6' key seems to be stuck. This doesn't affect my day-to-day usage at all, but whenever I change from the graphical console, I can't do anything because it keeps pressing '666666...'. Does anyone know why that might be happening? My keyboard is a Logitech G710+, and hasn't shown any other possible compatibility issues.

  Read the article

• Can I use metro style interface in my own web application?

  - by LukeP

  I am wondering if I would need to license the Metro style or if I can just freely use it in my own applications. I mean, is it patented or protected in any way that would prevent me from building my own implementation? I effectively would like to copy the visible part of it. I like to idea of being able to: Provide an interface which is used somewhere else (as in 1 less to learn) Use the interface that has been tested for usability (I personally like it) Have the possibility of getting free publicity because of implementing full Metro style web application while not associated with Microsoft, etc.

  Read the article

• Core-Plot: Unknown class CPLayerHostingView in Interface Builder file

  - by Snej

  Using core-plot does not seem to be an easy integration task. Header path are already setup. In Interface-Builder I create an CPLayerHostingView which belongs to a View Controller which is instantiated by Interface Builder. When the nib file is loaded I get the message: Unknown class CPLayerHostingView in Interface Builder file

  Read the article

• Spring 3 DI using generic DAO interface

  - by Peders

  I'm trying to use @Autowired annotation with my generic Dao interface like this: public interface DaoContainer<E extends DomainObject> { public int numberOfItems(); // Other methods omitted for brevity } I use this interface in my Controller in following fashion: @Configurable public class HelloWorld { @Autowired private DaoContainer<Notification> notificationContainer; @Autowired private DaoContainer<User> userContainer; // Implementation omitted for brevity } I've configured my application context with following configuration <context:spring-configured /> <context:component-scan base-package="com.organization.sample"> <context:exclude-filter expression="org.springframework.stereotype.Controller" type="annotation" /> </context:component-scan> <tx:annotation-driven /> This works only partially, since Spring creates and injects only one instance of my DaoContainer, namely DaoContainer. In other words, if I ask userContainer.numberOfItems(); I get the number of notificationContainer.numberOfItems() I've tried to use strongly typed interfaces to mark the correct implementation like this: public interface NotificationContainer extends DaoContainer<Notification> { } public interface UserContainer extends DaoContainer<User> { } And then used these interfaces like this: @Configurable public class HelloWorld { @Autowired private NotificationContainer notificationContainer; @Autowired private UserContainer userContainer; // Implementation omitted... } Sadly this fails to BeanCreationException: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.organization.sample.dao.NotificationContainer com.organization.sample.HelloWorld.notificationContainer; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No matching bean of type [com.organization.sample.NotificationContainer] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)} Now, I'm a little confused how should I proceed or is using multiple Dao's even possible. Any help would be greatly appreciated :)

  Read the article

• Storing Interface type in ASP.NET Profile

  - by NathanD

  In my ASP.NET website all calls into the data layer return entities as interfaces and the website does not need to know what the concrete type is. This works fine, but I have run into a problem when trying to store one of those types into the user Profile. My interface implements ISerializable, like the following: public interface IInsured : IPerson, IEntity, ISerializable and the concrete type in the datalayer does implement ISerializable. My Profile property in web.config is: <add name="ActiveInsured" type="FacadeInterfaces.IInsured" serializeAs="Binary" defaultValue="[null]"/> It compiles just fine, but I get a runtime error on Profile.Save() saying that the interface cannot be serialized. I have also tried it with serializeAs="Xml". I thought that if my interface implemented ISerializable it would work. Anybody had this problem before or know of a workaround?

  Read the article

• Java: why is declaration not sufficient in interface?

  - by HH

  Big class contains Format-interfcase and Format-class. The Format-class contains the methods and the interface has the values of the fields. I could have the fields in the class Format but the goal is with Interface. So do I just create dummy-vars to get the errors away, design issue or something ELSE? KEY: Declaration VS Initialisation Explain by the terms, why you have to init in interface. What is the logic behind it? To which kind of problems it leads the use of interface? Sample Code having the init-interface-problem import java.util.*; import java.io.*; public class FormatBig { private static class Format implements Format { private static long getSize(File f){return f.length();} private static long getTime(File f){return f.lastModified();} private static boolean isFile(File f){if(f.isFile()){return true;}} private static boolean isBinary(File f){return Match.isBinary(f);} private static char getType(File f){return Match.getTypes(f);} private static String getPath(File f){return getNoErrPath(f);} //Java API: isHidden, --- SYSTEM DEPENDED: toURI, toURL Format(File f) { // PUZZLE 0: would Stack<Object> be easier? size=getSize(f); time=getTime(f); isfile=isFile(f); isBinary=isBinary(f); type=getType(f); path=getPath(f); //PUZZLE 1: how can simplify the assignment? values.push(size); values.push(time); values.push(isfile); values.push(isBinary); values.push(type); values.push(path); } } public static String getNoErrPath(File f) { try{return f.getCanonicalPath(); }catch(Exception e){e.printStackTrace();} } public static final interface Format { //ERR: IT REQUIRES "=" public long size; public long time; public boolean isFile=true; //ERROR goes away if I initialise wit DUMMY public boolean isBinary; public char type; public String path; Stack<Object> values=new Stack<Object>(); } public static void main(String[] args) { Format fm=new Format(new File(".")); for(Object o:values){System.out.println(o);} } }

  Read the article

• Delphi interface cast using TValue

  - by conciliator

  I've recently experimented extensively with interfaces and D2010 RTTI. I don't know at runtime the actual type of the interface; although I will have access to it's qualified name using a string. Consider the following: program rtti_sb_1; {$APPTYPE CONSOLE} uses SysUtils, Rtti, TypInfo, mynamespace in 'mynamespace.pas'; var ctx: TRttiContext; InterfaceType: TRttiType; Method: TRttiMethod; ActualParentInstance: IParent; ChildInterfaceValue: TValue; ParentInterfaceValue: TValue; begin ctx := TRttiContext.Create; // Instantiation ActualParentInstance := TChild.Create as IParent; {$define WORKAROUND} {$ifdef WORKAROUND} InterfaceType := ctx.GetType(TypeInfo(IParent)); InterfaceType := ctx.GetType(TypeInfo(IChild)); {$endif} // Fetch interface type InterfaceType := ctx.FindType('mynamespace.IParent'); // This cast is OK and ChildMethod is executed (ActualParentInstance as IChild).ChildMethod(100); // Create a TValue holding the interface TValue.Make(@ActualParentInstance, InterfaceType.Handle, ParentInterfaceValue); InterfaceType := ctx.FindType('mynamespace.IChild'); // This cast doesn't work if ParentInterfaceValue.TryCast(InterfaceType.Handle, ChildInterfaceValue) then begin Method := InterfaceType.GetMethod('ChildMethod'); if (Method <> nil) then begin Method.Invoke(ChildInterfaceValue, [100]); end; end; ReadLn; end. The contents of mynamespace.pas is as follows: {$M+} IParent = interface ['{2375F59E-D432-4D7D-8D62-768F4225FFD1}'] procedure ParentMethod(const Id: integer); end; {$M-} IChild = interface(IParent) ['{6F89487E-5BB7-42FC-A760-38DA2329E0C5}'] procedure ChildMethod(const Id: integer); end; TParent = class(TInterfacedObject, IParent) public procedure ParentMethod(const Id: integer); end; TChild = class(TParent, IChild) public procedure ChildMethod(const Id: integer); end; For completeness, the implementation goes as procedure TParent.ParentMethod(const Id: integer); begin WriteLn('ParentMethod executed. Id is ' + IntToStr(Id)); end; procedure TChild.ChildMethod(const Id: integer); begin WriteLn('ChildMethod executed. Id is ' + IntToStr(Id)); end; The reason for {$define WORKAROUND} may be found in this post. Question: is there any way for me to make the desired type cast using RTTI? In other words: is there a way for me to invoke IChild.ChildMethod from knowing 1) the qualified name of IChild as a string, and 2) a reference to the TChild instance as a IParent interface? (After all, the hard-coded cast works fine. Is this even possible?) Thanks!

  Read the article

< Previous Page | 1 2 3 4 5 6 7 8 9 10 11 12  | Next Page >