I am very much confused about the words Component and Library.
I know the components are tightly bound, unit of functionality and modularity, and so does the library. In both the cases, binding is done at compile time. So what features make them different?
These are just two different words. Traditionally, anything that contain a bunch of things/code you can use is called a library. A bunch of C math function put together can be called a math library. A .NET DLL that contains a bunch of classes is called a class library.
The word Component comes from RAD tools and it implies some sort of design time support.
For example, a Windows Forms Menu class is a class that contains code implementing its runttime behavior (which is to display the menu in a window), but it also contains code that support certain things inside Visual Studio so that Visual Studio can design the menu at design time. It also has code that defines its "icon" in Visual Studio's toolbox, etc. All these things work together so that you can just drag it around on a "design surface" to make coding easier.
If you use .NET, there is an Object class which is the root of everything, and then there is the Component class that have a few members related to design time support. You can take a look of the class members which should give you an idea of what a Component is:
http://msdn.microsoft.com/en-us/library/system.componentmodel.component(v=vs.110).aspx
MS also has an article that explains it a bit more:
http://msdn.microsoft.com/en-us/library/vstudio/0b1dk63b.aspx
Needless to say, people often call class library that contains a lot of "Component classes" as a "component library". But there is nothing wrong to call it just class library.
Hope this helps a bit.
Related
I am aware of the "reinvent the wheel" objections to such an endeavor. However, I am interested in the DIY path mainly because I want to figure out for myself how to make it work. I've read a number of books and I needed to study VB.net for a different reason so I've explored doing this in VB (kill 2 birds with one stone type of reasoning). However, in Pro WPF 4.5 in VB (Apress), there is a passage which states:
"The RichTextBox control also exposes a rich programming model that provides plenty of extensibility points so you can plug in your own logic, which allows you to use the RichTextBox as a building block for your own customized text editor. The one drawback is speed. The WPF RichTextBox, like most of the rich text controls that have preceded it, can be a bit sluggish. If you need to hold huge amounts of data, use intricate logic to handle key presses, or add effects such as automatic formatting (for example, Visual Studio’s syntax highlighting or Word’s spelling-checker underlining), the WPF RichTextBox probably won’t provide the performance you need." (page 898-899).
No other guidance on this issue appears to be provided in the book. From what I've found online, it seems MS Office applications are still written in C++ and they obviously don't have these limitations. Are the performance issues here simply a function of this particular control where I can develop my own WPF controls which don't have these limitations or is this more a problem caused by the overhead of the .Net platform? I need to study VB.Net either way but I don't want to waste time using this project to learn it if .Net is not a good environment for developing such an application.
Create your own RichTextBox that inherits the standard RichTextBox
Public Class MyRichTextBox
Inherits RichTextBox
Public Shadows Sub Refresh()
End Sub
End Class
I'm a student and started developing some projects in VB.Net and I'm liking it a lot. However, I asked this question to some colleagues and they couldn't answer. Even my teacher wasn't able to clarify what was exactly VB and .Net. I have checked this question here but even the accepted answer gives me some doubts.
For example, for this bit of code here
Class Example
Private _value As Integer
Public Sub New()
_value = 2
End Sub
Public Function Value() As Integer
Return _value * 2
End Function
End Class
Module Module1
Sub Main()
Dim x As Example = New Example()
Console.WriteLine(x.Value())
End Sub
End Module
How can the language be separated from the framework? I know the language is syntax and all but, where is the framework?
I've read that frameworks contain libraries: what are exactly libraries? The language (syntax and all) I can see it, it can be seen, but is the framework visible too? If so, where?
So in a VB.Net application, when I look at the code, all I can see is VB: the same goes for C#.Net applications.
Maybe silly example: For instance, for a car to function, all components must be good - from the tires to the hood, the engine, the fuel - but all of them are visible, and while from the outside we can't see the oil or fuel running inside or the pistons working, we can see them if we want.
Is it possible to see all the components when looking at a VB/C# .Net application? I mean, to look at code and clearly distinguish what is VB or C# and .Net?
Thanks
There are three primary parts to the .NET framework:
Compiler (MSBuild)
Runtime environment (CLR) - virtual machine, garbage collector, etc.
Supporting libraries (FCL)- System, ADO.NET, LINQ, WPF, WCF, etc.
All three of the above are included with the freely-distributed .NET Framework. The term .NET Framework refers collectively, and loosely, to all of those things, but they each perform very different roles. The answer to your question is different for each of those parts.
Compiler
As you probably know, you cannot run VB.NET code directly. It must first be compiled into an executable which can be launched as a Windows process. The compiler is used to compile a variety of high level languages (such as VB.NET and C#) into assemblies (e.g. EXEs, DLLs). Unlike native compilers, though, .NET assemblies do not contain native machine code. Instead, the .NET compiler compiles into .NET assemblies which contain MSIL code. MSIL is a slightly-higher-level-than-machine-code language which, in theory, can be run by a virtual machine on any platform.
The compiler is obviously not visible in your code. Obviously there is no place in your code where you can say "that's the compiler". Rather, the compiler is the tool that you use to compile all of your code. The compiler, though, does dictate what languages you can use. If the .NET framework does not contain a Ruby compiler, then you can't very well write a .NET application in Ruby. So, in that way, the fact that your code is written in VB.NET or C# at all is the indication that it will be compiled using the .NET Framework.
You may be thinking, "The compiler isn't part of the framework--that's part of Visual Studio." But if you were thinking that, you would be wrong. The compiler is installed as part of the .NET framework. You don't technically need Visual Studio to compile a .NET application. You could write an application in any .NET language, using Notepad, and then compile and run it with the .NET Framework without ever having installed Visual Studio.
The compiler portion of the .NET Framework is referred to as MSBuild.
Runtime Environment
Since the compiler compiles your high-level code into MSIL assemblies, rather than into native machine-code binaries, you must have the .NET Framework installed in order to run any .NET application. When you run a .NET application, the Framework is responsible for just-in-time (JIT) compiling the MSIL code into machine code so that it can be executed on your current platform. It also provides the memory management features such as garbage collection.
The same runtime environment is shared by all .NET languages (since all .NET languages compile to MSIL code). Therefore, it's not a VB.NET runtime environment nor a C# runtime environment, but rather, it's a MSIL runtime environment. Instead of having one runtime environment per language, there is actually one runtime environment per platform. A separate environment must be custom implemented for each processor architecture and each operating system on which the Framework will run.
This part of the framework is largely invisible to you and your code. There are some methods you can call to access the GAC, or the garbage collector, or the .NET security system, but other than that, you don't even know it's there. Unless the Framework isn't installed, that is--in that case, it becomes clear very quickly just how necessary it is.
The runtime-environment portion of the .NET Framework is referred to as the Common Language Runtime (CLR).
Supporting Libraries
The .NET Framework comes packed with many extraordinarily useful libraries (DLLs). For instance, every application references the mscorlib.dll and System.dll libraries, which provide many of the core data types in the System namespace. There are many other libraries which you can optionally reference with your projects as necessary.
These supporting libraries are provided as already-compiled MSIL assemblies, so they can all be referenced and used by projects written in any .NET supported language. When you call Console.WriteLine("Hello World") in VB.NET and Console.WriteLine("Hello World"); in C#, you are calling the exact same .NET Framework library. The Console class is defined in the mscorlib.dll library. It doesn't matter which language you use to call it, it always does the same thing.
The supporting libraries are very visible in your code. Any time you use anything that is not explicitly defined by you in your own code, you are using the Framework (unless, of course, it's something from a third-party library). In your example code above, you are using Integer and Console. Both of those types are defined by the .NET Framework's supporting libraries (both are defined by mscorlib.dll). In other words, the language is all of the syntax that you use to make the calls to the Framework. Everything else is the Framework.
If you want to "see" the supporting libraries, the best place to start is in Visual Studio. You can use the Object Browser to browse through all of the types defined by the libraries that you currently have referenced in your project. If you want to reference more .NET Framework libraries, go to your Project Properties designer's References tab, click the Add... button, then select the Asseblies > Framework option. That will list all of the supporting libraries that are provided as part of the .NET Framework. If you want to find out more about any of the functionality provided by any of those libraries, your best resource is the MSDN (and Stack Overflow, of course).
The supporting libraries portion of the .NET Framework is referred to as the Framework Class Library (FCL).
Here is how I envision the two
The framework is the set of libraries, APIs and runtime components that are available for the language to use
The language is the syntax by which the framework is accessed
In many cases it's hard to separate the two because the language when used is nearly always accessing some part of the framework. Take for instance even this very simple definition
Class Example
End Class
Even though it is unstated, this definition depends on the targeted framework having a definition of System.Object. This is necessary for the language to setup the appropriate base class for Example.
You have to keep in mind that if you're using a programming language, at some point it all must boil down to binary 1's and 0's.
This means that when your program gets compiled and run, it's making use of the C# compiler. The C# compiler is a program written in a native language (probably c or c++). This program allows yours to be converted into stuff that the .net framework runtime can understand. Essentially, your C# code becomes some sort of intermediate bytecode.
Similarly, after your program is compiled into this intermediate bytecode, it is run on top of a virtual machine (JVM for Java or the .net framework runtime for C#). This virtual machine is a pre-compiled program written in a native language (c or c++), which allows your program to interface with the computer's processor in a way that both understand.
All of these pre-written, pre-compiled pieces are part of a framework. They are installed to your machine in some particular location (which is why they might not be readily visible with the rest of your code and assets) and provide APIs to anything that wants to make use of them.
The APIs are analogous to the understanding between a gas pedal and an engine. An engine accepts more fuel as a result of someone pressing the gas pedal. In some sense, the engine "talks" to the gas pedal and understands that if you press firmly on the pedal, the engine should respond by injecting more gasoline into the combustion chambers.
These individual pieces, along with their "understandings" represent a framework. You might add a "Driver" who can operate a gas pedal as your "C# Application".
How can the language be separated from the framework?
For example... take for instance English, English is a language, while a book would be a Framework. In this example, you can write whatever you want in English, but you can't write in "The Hobbit", because it is a book, not a language.
However, you can make references to the book. For instance you can talk about Trolls, and you don't have to define it's behavior or looks, because the book already defines them for you.
Where is the framework?
The framework exists whenever you make reference to it. In the Trolls example, if you ask "Do you know how do Trolls look like?", I would need a context for that, it may be Harry Potter's, Tolkien's, World of Warcraft's, etc. And I will give you compilation errors because I can't understand you.
If however we "use" the same "Framework" (book), or if you tell me about them before, I would be able to respond you (compile).
Is the framework visible too? If so, where?
VB/C# are languages, you can't "really see" where it is, because you write it. It is like asking where is English. You can however compile it, and that is what you can "find", just like you can find a printer.
The Framework is a set of libraries/utilities already packed into a beautiful black box that you download and trust your life to.
VisualStudio helps you a lot, and it will hide "complicated stuff", imagine like it is a movie called The Lord of The Rings, and it removes a lot of stuff that you can't really look into unless you read the book.
You can't really dive into "what .NET does internally", because it is closed software. Imagine that I burn down all the books and you have to trust the movie.
But you could use an Open Source example such as Struts (a JavaEE Framework) because it is open source (books should not be burned in Open Source examples).
Here is an abstract example.
Speech is similar to a framework, you have phonation, producing sound;
resonance; intonation, variance of pitch, etc. Those are all the building blocks for communicating.
To speak a specific language, you must utilize phonology, morphology, language syntax, proper grammar; semantics, etc - all the rules for that Language.
...
In a programming framework, you have building blocks (code libraries, dependent files, specific folder/file layout, ect.) that you might need to complete a programming task.
A programming language is the set of rules you must abide to in order for your application to correctly work.
....
In the Java programming language, I could open notepad and write java code, compile it, and run it on any machine that has the JVM installed.
Java Server Faces (JSF) is a framework where a Model-View-Controller (MVC) paradigm exists as the basis to run web applications. You have necessary dependent files (like web.xml) that must exist for the server to correctly implement, structured layout of classfiles, and implementation/configuration of other libraries. In an essence, your files are still written in the Java Programming language and your syntax must be correct, but if you want to build a web application using that framework, you must have adhere to those other specific patterns and constraints.
I am working on a silverlight project and I am using MEF to download xap file of other silverlight project and use its pages and functions in my main Project.
I can do the same thing using referencing dll of that project into my main project.
So I want to know what is the difference between using MEF to reusing components and Simply Adding Reference to the DLL of another project in current project? I mean that we also add reference to the project we import in our current project. Then how it is different from conventional form of component use?
Thanks,
First, we need to separate MEF and PRISM (since you used it in your tags).
MEF is primarily used to provide inversion of control (IoC). It makes it easy to manage dependencies your viewmodels and other classes to separate concerns and improve testability (amongst other benefits).
PRISM however is primarily designed for the following scenario: You don't know, what view goes into a specific container at compile time, and want ViewA for CustomerA, ViewB for CustomerB and so on. PRISM helps you to losely couple your regions and views in a way, so that the application can decide at runtime, what view will be displayed. Another scenario, is that administrators get one view, other users another etc. PRISM also has other features (like the event aggregator), but I'd say the former is the most important one.
Now, I'd say MEF is never a bad thing to use for a bigger project. But I'd only use PRISM, if you really need the functionality it provides, since it can be very limiting. If you don't, simply add the references as you explained and let MEF know about those assemblies with the AssemblyCatalog.
So for MEF, I'd suggest you learn about Depdendency Injection and IoC. I found this blogpost by Martin Fowler quite good. As for PRISM, get familiar with what it does, and decide if you really need it.
Hope this helps.
Let me complement Lue's answer on the difference between MEF and referencing dlls a bit:
The two things are orthogonal activities, meaning that if you reference a dll directly you might still want to use MEF to detect the types in it - and vice versa you might grab a specific type in a dll you dynamically loaded directly (without MEF).
MEF basically finds types in dlls according to certain criteria and has a bit of convenience stuff in it to automatically populate properties and collections with such types. It can be used to make a system more decoupled and thus more maintainable. For example, a video editing software may look for all types implementing a certain interface in all known dlls to use as filters. Whether you include the filters directly as a dll or let the user download them on demand: In both cases your application becomes slightly cleaner by using MEF, since there is no hard-coded list of filters anywhere. Still, in the presence of dynamic library loading MEF is especially useful.
I want to create an ActiveX DLL from Visual Basic 6 from which I would like to call some public functions. I will call this DLL only from VB6. However, it seems that only classes get exported. Is there any workaround?
I know there is a way to create DLLs from VB6 with standard WINAPI functions. This is not what I want, because I would have to type thousands of Declare instructions, and I would lose the dynamic linking so I don't need to recompile applications when changing the DLL.
I will state my problem just in case anyone has a better idea. I've got a bunch of relatively big projects, each with its own code, and then I have a lot of "Generic" code which is used in several projects. It's an annoyance to add every file to each new project, and having to recompile all of them for each minor change. So I thought of creating a DLL, so I would just "Add reference" when I begin a new project, and don't have to worry anymore about recompiling (at least for minor changes) but I raged when discovered that only classes got exported.
I wouldn't mind to reorganize the code in classes, but it's an overwhelming task: there are some 10 years of 3-4 people code, so it's not something I can do overnight.
Yes, it's easy.
Put all the utility routines in special classes in the DLL.
Set the Instancing property of those classes as GlobalMultiUse.
Build the DLL.
In your client project (with a reference to the DLL) you will now be able to call the functions and subroutines as if they were in a module in that project. You won't need to create any objects.
You can read more in the VB6 manual.
I'm a complete Xcode/Objective-C/Cocoa newbie but I'm learning fast and really starting to enjoy getting to grips with a new language, platform and paradigm.
One thing is though, having been using Visual Studio with R# for so long I've kind of been spoiled with the coding tools such as refactorings and completion etc and as far as I can tell Xcode has some fairly limited built in support for this stuff.
On that note, does anyone know if any add-ins or whatever are available for the Xcode environment which add coding helpers such as automatically generating implementation skeletons from a class interface definition etc?
I suspect there aren't but I suppose it can't help to ask.
You sound as if you're looking for three major things: code templates, refactoring tools, and auto-completion.
The good news is that Xcode 3 and later come with superb auto-completion and template support. By default, you have to explicitly request completion by hitting the escape key. (This actually works in all NSTextViews; try it!) If you want to have the completions appear automatically, you can go to Preferences -> Code Sense and set the pop-up to appear automatically after a few seconds. You should find good completions for C and Objective-C code, and pretty good completions for C++.
Xcode also has a solid template/skeleton system that you can use. You can see what templates are available by default by going to Edit -> Insert Text Macro. Of course, you don't want to insert text macros with the mouse; that defeats the point. Instead, you have two options:
Back in Preferences,go to Key Bindings, and then, under Menu Key Bindings, assign a specific shortcut to macros you use often. I personally don't bother doing this, but I know plenty of great Mac devs who do
Use the CompletionPrefix. By default, nearly all of the templates have a special prefix that, if you type and then hit the escape key, will result in the template being inserted. You can use Control-/ to move between the completion fields.
You can see a full list of Xcode's default macros and their associated CompletionPrefixes at Crooked Spin.
You can also add your own macros, or modify the defaults. To do so, edit the file /Developer/Library/Xcode/Specifications/{C,HTML}.xctxtmacro. The syntax should be self-explanatory, if not terribly friendly.
Unfortunately, if you're addicted to R#, you will be disappointed by your refactoring options. Basic refactoring is provided within Xcode through the context menu or by hitting Shift-Apple-J. From there, you can extract and rename methods, promote and demote them through the class hierarchy, and a few other common operations. Unfortunately, neither Xcode nor any third-party utilities offer anything approaching Resharper, so on that front, you're currently out of luck. Thankfully, Apple has already demonstrated versions of Xcode in the works that have vastly improved refactoring capabilities, so hopefully you won't have to wait too long before the situation starts to improve.
I'm excited to say that JetBrains have decided to make a decent IDE for Objective-C coders.
It's called AppCode and it's based on their other tools like RubyMine and Resharper. It's not native Cocoa, but has loads of raw refactoring power.
http://www.jetbrains.com/objc/index.html
I've started using it for my main Objective C project and I'm already in love. It's still in it's infancy, but for code editing and refactoring it already blows Xcode away.
Update
It's now at a totally usable speed. I've switched over to it full time and it still blows my mind how amazing refactoring and coding is compared with Xcode. It just handles so much for you - auto importing, almost infinite customisation. It makes Xcode look like a toy.
Xcode has refactoring for C and Objective-C built in. Just select what you'd like to refactor, choose "Refactor..." from either the menu bar or the contextual menu, and you'll get a window including the available refactorings and a preview area.
Xcode doesn't currently have a public plug-in API; if there are specific types of plug-ins you'd like Apple to enable, file enhancement requests in the Bug Reporter. That way Apple can count and track such requests.
However, there are third-party tools like Accessorizer and mogenerator (the latest release is mogenerator 1.10) that you can use to make various development tasks faster. Accessorizer helps you create accessor methods for your classes, while mogenerator does more advanced code generation for Core Data managed object classes that are modeled using Xcode's modeling tools.
Just so people know, Accessorizer does more than just generate accessors (both 1.0 and properties for 2.0) it also generates Core Data code for persisting non-standard attributes, your NSSet accessors for custom to-many relationships.
In fact, Accessorizer will help provide you with the init, keypath, keyed-archiving, indexed accessors, accessors for unordered collections such as NSSet, copyWithZone, KVO, key-validation, singleton overrides, dealloc, setNilForKey, non-standard attribute persistence (Core Data), locking, headerdoc, convert method to selector, NSUndoManager methods and more.
I found some xtmacro files in Xcode.app package:
/Developer/Applications/Xcode.app/Contents/PlugIns/TextMacros.xctxtmacro/Contents/Resources
Installed Xcode ver. 3.2.5.