Could/Should Use Static Classes In C# For Shared Data?
May 7, 2010
I'm building an online system to be used by school groups. Only one school can log into the system at any one time, and from that school you'll get about 13 users. They then proceed into a educational application in which they have to co-operate to complete tasks, and from a code point of view, sharing variables all over the place.
I was thinking, if I set up a static class with static properties that hold the variables that are required to be shared, this could save me having to store/access the variables in/from a database, as long as the static variables are all properly initialized when the application starts and cleaned up at the end. Of course I would also have to put locks on the get and set methods to make the variables thread safe.
Something in the back of my mind is telling me this might be a terrible way of going about things, but I'm not sure exactly why, so if people could give me their thoughts for or against using a static class in this situation,
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Mar 4, 2010
I have a base class with several derived classes. I want all of my derived classes to have the same Public Shared (static) method with their own implementation. How do I do this?
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Jan 20, 2010
I've read several other questions on this topic (here, here, and here), but have yet to see a great answer. I've developed my fair share of data access layers before and personally prefer to use instance classes instead of static classes. However, it is more of a personal preference (I like to test my business objects, and this approach makes mocking out the DAL easier). I have used static classes to access the database before, but I've always felt a little insecure in the appropriateness of such a design (especially in an ASP.NET environment).
Can anyone provide some good pros/cons with regards to these two approaches to developing data access classes with ADO.NET providers (no ORM), in an ASP.NET application in particular. Feel free to chime in if you have some more general static vs. instance class tips as well.
In particular, the issues I'm concerned about are:
Threading & concurrency
Scalability
Performance
Any other unknowns
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Jan 29, 2011
I'm totally new to the Microsoft dev scene so please go easy :)Currently, I have a solution that contains two projects (ASP.net websites, FWIW). If I create a class in Project1, how do I expose it to Project2? Is it automatically available to Project2 because they are in the same solution? Or do I need to do something special to make the connection?
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Oct 4, 2010
I have some code in my new asp.net app that I need to share. So i created a shared class called
"utilities.vb" and put it in the APP_CODE folder. There is a function I have in there that pulls a person's image based off of their MemberId.
[Code]....
And I can call this function from my page using utilities.FcnGetMemberImage(). Ok, so all good so far until it complains about...
"Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class"
when referring to the Server.MapPath()
But the problem is that if I don't make it a Shared Function, I can't access it from my other pages. But if I do make it a Shared Function, it throws this error. The fix is supposed to be that I either don't share the function, or
"add the shared keyword to the member declaration", according to Microsoft at
http://msdn.microsoft.com/en-us/library/xfsswe45.aspx
But I'm not exactly sure how to "add the shared keyword to the member declaration" or what this means exactly and how this might affect other parts of my code?
Or is there a better way to work around this dilemma?
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Jul 9, 2010
Whenever I create a new folder in my website (VS008) and add an item (Class) it can't be seen by the other pages, even though new class is public. Only if I add the class to the app_code folder or create a bin folder for it then it could be shared from these folders however I want to create my own custom named folders for organization and keep my classes there.
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Feb 20, 2011
VWD 2010 Express.
We have shared CSharp classes put into a shared folders for re-use. Now I want to add those classes into my project by creating a new folder:
1) Right click the solution,
Add -> New Folder
Give it a new, eg. SharedClasses
2) Right click the new folder "SharedClasses"
Add- > Existing Item...
Browse to the "Shared Folder", include those shared classes. But those files are added physically into the folder "SharedClasses" rather than a reference. How do I just add a link to those shared files? Since these files might be modified from time to time, I don't want to delete and add those file frequently.
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Aug 20, 2010
I get this error: Cannot refer to an instance member of a class from within a shared method or shared member initializer without an explicit instance of the class.
Partial Class _Default
Inherits System.Web.UI.Page
<WebMethod()> _
Public Shared Function ParseData() As String
Dim value as string = GetValue()
End Function
Private Function GetValue() as String
Return "halp"
End Function
End Class
I know it has something to do with the fact that the first function is shared and the second function should probably be Public as well but I don't fully understand the reason behind it. Probably not relevant but I'm calling the web method from some javascript.
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Nov 11, 2010
For reasons I would rather not discuss, I need to create a custom authentication system for my app. I was just reviewing the system and am having some doubts if my solution is thread safe. My goal was to create a solution that would allow my app to authenticate a user one time and that users authentication info would be shared by all master pages, pages, classes, user controls, etc that are used. (But not share the same info between users) Here is my setup: PageHttpModule.cs - this is added to the web.config as a httpModule.
public class PageHttpModule : IHttpModule
{
public void Init(HttpApplication app)
{
app.AuthenticateRequest += new EventHandler(OnAuthenticateRequest);
}
public void OnAuthenticateRequest(Object s, EventArgs e)
{
CurrentUser.Initialize();
}
public void Dispose() { }
}
CurrentUser.cs
public static class CurrentUser
{
public static bool IsAuthenticated { get; private set; }
public static string Email {get; set;}
public static string RealName {get; set;
public static string UserId {get; set;}
public static void Initialize()
{
CurrentUser.AuthenticateUser();
}
Note: this is a scaled down version of my authentication code.
public static void AuthenticateUser()
{
UserAuthentication user = new UserAuthentication();
user.AuthenticateUser();
if (user.IsAuthenticated)
{
CurrentUser.IsAuthenticated = true;
CurrentUser.UserId = user.UserId;
CurrentUser.Email = user.Email;
CurrentUser.RealName = user.RealName;
}
}
}
UserAuthentication.cs
public class UserAuthentication
{
public string Email { get; set; }
public string RealName { get; set; }
public string UserId { get; set; }
public bool IsAuthenticated { get; private set; }
public UserAuthentication()
{
IsAuthenticated = false;
Email = String.Empty;
RealName = String.Empty;
UserId = String.Empty;
}
public void AuthenticateUser()
{
//do some logic here.. if the user is ok then
IsAuthenticated = true
Email = address from db
UserId = userid from db;
Realname = name from db;
}
}
I have tested between 3 different browsers and it seems to work fine, but I am still learning and don't want to make a huge mistake. If my logic is totally wrong, then how should I do it so I dont have to put user lookups on every page directly?
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Apr 30, 2010
If for example you have a function Public shared function GetStockByID(StockID as Guid) as Stock Is that function common to all current users of your application? Or is the shared function only specific to the current user and shared in the context of ONLY that current user? So more specifically my question is this, besides database concurrency issues such as table locking do I need to concern myself with threading issues in shared functions in an ASP.Net application?In my head; let's say my application namespace is MyTestApplicationNamespace. Everytime a new user connects to my site a new instance of the MyTestApplicationNamespace is created and therefore all shared functions are common to that instance and user but NOT common across multiple users. Is this correct?
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Sep 16, 2010
my understanding static/shared objects will be saved in a memory that is shared by all instances of the asp.net application,so if we set a value to shared object from inst1 & i should be able to access it via instance2(may be in same computer or anywhere)Actually:In my vb.net application,previously they defined shared dataset to hold some information specific to the user,still now i cant reproduce the error that same value shared across all application instances.Please help me to solve or clarify this.
[URL]
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Feb 8, 2010
I am using DataClassesDataContext to map all the tables from the db into my asp.net application.For doing CRUD operations i have made static classes with methods, and inside every method a instantiate DataClassesDataContext.For instance:
public static class UserQ
{
public static User getUserById(int userId)
[code]...
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Jul 3, 2010
Currently I have my data cached in Datasets in a static class. I was talking to my cousin's husband, who works as a C# developer for our local Telecom company.
Basically, I'm pretty new to ASP.NET and although to me having cached data in a static class makes sense to me, when I talked to him about it, he said there might be a problem when the site goes live, as on a web server more than one instance of the class may be created.
He did say this was a theory, and it was an area he didn't know an awful lot about, so I thought I'd ask some of you ASP.NET gurus to see if what I've done is totally wrong or not.
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Jan 11, 2010
So I started working on my first asp.net application that involves logging in and databases, and soon after i started messing around with a static class. I "discovered" that if you make a variable static, all sessions share that variable (I for some reason was originally assuming that each session had its own copy of that "static" class). Anyway, after discovering this I thought to myself "how could this possibly be useful to me" and thought that itmight be a good idea to make a single static database connection for all of the sessions, rather than storing that as a session variable for each session. Does anybody know what would be the pros and cons of this approach?
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Aug 16, 2010
I have an extension method as follows:
public static class PageExtensions
{
public static int GetUserId(this Page targetPage)
{
var user = Membership.GetUser(targetPage.User.Identity.Name);
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Now in a page I need to use this method in a static WebMethod, so I have added another 'extension method' to PageExtensions:
public static int GetUserId()
{
return (int)Membership.GetUser(HttpContext.Current.User.Identity.Name).ProviderUserKey;
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Jan 5, 2010
let me know what does these access modifiers means.private shared vs public shared vs protected shared
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Jan 11, 2010
I am new to LINQ. when we drag tables we get a dbml file and designer file.
For example DataClasses1.dbml and DataClasses1.designer.cs.
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In my company project I do not see this designer files and instead there are .tt files which were used as templates to greate ABC.generated.cs files. Is this same as designer class?
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May 17, 2010
I am following the Nerd Dinner tutorial as I'm learning ASP.NET MVC, and I am currently on Step 3: Building the Model. One part of this section discusses how to integrate validation and business rule logic with the model classes. All this makes perfect sense. However, in the case of this source code, the author only validates one class: Dinner.
What I am wondering is, say I have multiple classes that need validation (Dinner, Guest, etc). It doesn't seem smart to me to repeatedly write these two methods in the partial class:
[code]....
This doesn't "feel" right, but I wanted to check with SO to get opinions of individuals smarter than me on this. I also tested it out, and it seems that the partial keyword on the OnValidate method is causing problems (understandably so). This doesn't seem possible to fix (but I could very well be wrong).
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Aug 11, 2010
I don't know if this has to do with how FindControl works or how scope works. But my base class is having a hard time seeing the fields of child classes. Currently I'm planning have the derived class set a property in the base class, but there are a lot of derived classes, so that isn't a very attractive solution.
[code]....
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Mar 24, 2010
Can I use VB and C# classes together in the same asp.net 3.5 project?
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May 10, 2010
Is it safe to access asp.net session variables through static properties of a static object?Here is what I mean:
public static class SessionHelper
{
public static int Age
{
get
{
[code]...
Is it possible that userA could access userB's session data this way?
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Dec 15, 2010
I'm curious as to what people consider better practice, between duplicating model structure in the view model and using a mapping tool to move data between the two, or aggregate the model inside the view model, i.e. have a property on the view model class that is a reference to the actual model. Which is considered a better approach in general?
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Mar 26, 2011
I have a private static field in my Controller class in an MVC web application.
I have a static method in that controller that assigns some value to that static field, I want to apply lock on that static field until some other instance method in the controller uses the value stored in the static field and then releases it.
DETAILS:
I have a controller named BaseController having a static ClientId field as follows and two methods as follows:-
public static string ClientId = "";
static void OnClientConnected(string clientId, ref Dictionary<string, object> list)
{
list.Add("a", "b");
// I want the ClientId to be locked here, so that it can not be accessed by other requests coming to the server and wait for ClientId to be released:-
BaseController.clientId = clientId;
}
public ActionResult Handler()
{
if (something)
{
// use the static ClientId here
}
// Release the ClientId here, so it can now be used by other web requests coming to the server.
return View();
}
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Jun 30, 2010
I did some research after posting. All I found was simple examples for no-layer architectures, like connecting to a database from your aspx page, so, in a corporate environment, it is unnaceptable.
I need to call a server-side method (using ASP.NET Ajax) in a 3-layer architecture.
For example, my Default.aspx contains a method LoadProducts().
[Code]....
[Code]....
This cannot change. There is no way to convert Business and Data layers to static.
How can I call the LoadProducts() method using ASP.NET Ajax?
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Jan 27, 2011
I have a question about C Sharp ASP.NET:Is there a difference (in code speed, resources) between:public static variable declared in public static class MyGlobals in a 'Code File' template;and the variable declared in a normal 'Class File' template;I use this variable in 2 different Class Files and also in _Default Page codebehind cs file.In fact in my case I need about 20 global variables of type List<string>.
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