Little stuck, i need to use Request.IsLocal inside a class library, not the web project. How should i be dong this?
System.Web and System.Web.Mvc are referenced in there.
var isLocal = System.Web.HttpContext.Current.Request.IsLocal;
No, I am kidding. Promise me you will never do anything like that. You shouldn't need something like this in a class library. Or if you need it, you should pass this information to the class library as, for example, method argument from the UI layer which has the notion of Request. Otherwise you will tying your class library to ASP.NET and an HttpContext making it non-reusable.
Related
In Xamarin forms app, How can we invoke Shared code Method from Platform specific Dependency class.
I need to call one method implemented in my ContentPage class from my iOS dependency class.
Thanks...
There are different solutions to this:
Use a static method to call it where ever you need to.
Use the messaging center to send a message to your Shared/PCL project and do what ever you need. (link: https://developer.xamarin.com/guides/xamarin-forms/application-fundamentals/messaging-center/)
If this is a Custom renderer you can use binded command properties and Execute those in your platforms specific code.
In my case, what I did was having a static class called Helper, that contains all the static methods that I need to call on all platforms/projects.
Hope this helps.
I always got problems with the private variable declaration.
For example FlatFileItemWrite. I would like to extend these class and overwrite the 'doRead' method. This would not work because some of the used variables are declared private. This leads to copying the complete code in an own class for overwriting one method.
Sometime even this does not work because the class extends an other class which has variables declared visible only for the same package. Then you need to copy this class also.
Then I will miss updates in the original classes with new versions. So would it not be better to use protected instead?
I can imaging only a very few reasons to use private instead of protected. For my own programs this is not an issue, I could change it on demand. But for a framework it is a pain.
with kind regards
Torsten
If something is declared private within the Spring framework (or any framework for that matter), it's not considered part of the public API. Because of that, you really shouldn't be looking to work with it directly. Doing so really means you're forking the framework and risking not being able to upgrade seamlessly.
As the project lead for Spring Batch, I'd be interested in hearing what you had to do with the FlatFileItemWriter that required you to change things that are marked private.
If the idea behind the framework was to override or extend these methods, they should have been written as being public. (be careful if a framework does not provide these methods or properties as public, since it might depend on them working in a specific way. this would be the primary reason for them being private i can think of. the secondary being that they don't matter outside that class.)
In some cases, you might not need to copy the entire class, but simply inheriting or extending it might be enough.
I'm also looking to extend certain ItemReaders/ItemWriters to support decryption/encryption on i/o. For example, I'd like to extend StaxEventItemReaderStaxEventItemReader in order to read an encrypted stream from the resource, but the FragmentEventReader is private, so I'm unable to wrap its XMLEventReader's InputStream in a decrypter.
I faced the same issue with FlatFileItemWriter.
So, I am creating a class library that handles user information like username, password, etc. I want to do this so that I can just reference this library with any of my web apps and not have to continuously rewrite the user information part.
In, the user information class library, I want to handle the login. I've done this before in app_code that was a part of the web project by using HttpContext.Current.Session. But, when I try to use it in my class library (even while using System.Web) it throws a compile error saying that HttpContext does not exist in this context. How can I get access to it?
When creating a utility type class that works with a dependency like HttpContext, your best bet is to pass the context or the session into the class either via a constructor or the method call. That way, it is explicit to the consumers of your class that it requires this object to function. This also allows you to test your class in isolation.
Even better, if you are working with a few specific properties that have basic types then you can accept those properties as inputs. That way, you are not creating any dependencies on a UI framework for your utility library.
hi i am having a different projects in my solution in the initial project (default project) i am accessing the global reference to App.xaml.cs in this way :-
App objref = (App)Application.Current;
But now i have added new project to my solution and trying to access the app.xaml.cs in the same way as defined earlier but i am not able to access app.xaml.cs ?
1)can i know the reason
2)What should i do if i want to use it in both the projects ?
Please let me know
Thanks in advance.
You can access it, but the new project will not be familiar with the derived App class that is in your project. To explain further we need to take inheritance into consideration.
There's a generic definition for the Application class that exposes a number of predefined methods. Your App.xaml.cs is a new class definition that is derived from the Application class. It has the methods it inherited plus what ever methods and properties that you've added. To make use of these any code that is seeking to use your extra properties or methods must have access to the class definition. Your classes in the other projects that you've added do not have access to this definition.
You'll need to make a class or interface definition that both projects have access to. There are several ways of organizing this. I'll present one.
Create your main project in the solution. This contains your
App.xaml.cs.
Create your class library project that contains the
other code.
Create a third project called Common that only contains
an Interface definition.
On the Interface definition define all of the methods/properties
that you want both your class library and main project to have
access too.
Have App.Xaml.cs implement this interface.
In the Class Library access var appReference =
(IMyInterfaceName)Applcation.Current. You'll have access to the
methods that were defined in the interface
I would like to write and read data to Session even if my class not inherited from controller or helper. Something like this:
public class User
{
public void CreateSession()
{
Session["key"]=data;
}
public void ReadSession()
{
data=(string)Session["key"];
}
}
Important thing - I need to get instance of User class in some actions
and views. Am I be able to inherit User class from controller or
helper. Because I've already try that, but I got some errors.
How can I achive this?
Thanks in advance.
HttpContext.Session will work, it's a static available anywhere to an assembly that references System.Web.
If your code is in your main website assembly, this should work well. If it's not, you'll have to create a dependency on System.Web which you may or may not want to do.
You should do these kind of things in your controller.
You can access HttpContext directly, but that's not "the ASP.NET MVC way", and you loose some of the advantages of using MVC in the first place. Like making testing harder, and directly coupling your application to HttpContext...
Also, if it's a new session, or Session["key"] is not set for some reason, data=(string)Session["key"]; would throw a null reference exception.