C# - Is Using Private Shared Objects/variables On Class Level Harmful
May 28, 2010
In page behind classes I am using a private and shared object and variables (list or just client or simplay int id) to temporary hold data coming from database or class library. This object is used temporarily to catch data and than to return, pass to some function or binding a control.1st: Can this approach harm any way ? I couldn't analyze it but a thought was using such shared variables may replace data in it when multiple users may be sending request at a time?
In page behind classes I am using a private and shared object (list<client> or just client) to temporary hold data coming from database or class library. This object is used temporarily to catch data and than to return, pass to some function or binding acontrol. 1st: Can this approach harm any way ? I couldnt analyse it but a thought was using such shared variables may replace data in it ?2nd: Please comment also on using such variables in BLL (to hold data coming from database) where new object of BLL class will be made everytime.
Since we can access the private data member of base class in the derived class with the help of friend function. How can we do the same in C# asp.net? I mean whats the alternative of friend function in C# asp.net
I'm developing a server control and I'd like to set some cache and application level variables but I don't want them to be visible from outside the control. Is this possible?
In an ASP.NET web app written in VB.NET, I need to load and store a large read-only hash table that is frequently accessed by the application. It only needs to be loaded once on application start, is never updated and can be accessed by any session at any time.
If I load the hash table into a private member in a (global) module, a lookup to it takes one 20th of the time compared to storing the hash table in the Application or Cache object. Is there any reason why I should not do this, or should Application or Cache always be used to store in-memory objects in an ASP.NET web application?
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?
I'm working on a page with two sets of collapsable panels. using nHibernate) I get category objects with a list of items in them, and for each category generate a left panel and right panel. In both panels, there is a ListBox. Items are pre-populated to the left list box and the user can select and move items into the right list box (under the corresponding category.) As I've built and worked on it, I ended up with a lot of generic methods like buildPanel(side,categoryID) and then ended up with a lot of repeated if statements inside them to differentiate between the two sides
if type=PanelType.Left then set these 5 id strings to access components else ...
The code got messy, so I moved a lot of the logic and static builder strings for the component ids into a private helper class in order to make other parts of the main class easier to read and follow. The problem I see is that the private class is extremely dependant on specific structures in the parent class. There's a very minimal amount of encapsulation going on and I'm possibly making the logic harder to follow even if the individual components in the code are easier to read.
My question is: When you're using a private class like this, is it acceptable to have it tightly integrated with the parent class (since it's private and implemented in the same file), am I better to refactor again and find a way of either simplifying my original code to be as short as possible without the helper class (stick all category/panel functions in one spot and hide them in their own region when I'm not using them), or should I move towards putting more of the logic in the helper class and simply mapping my events directly to the subclass. After typing all this out, I'm leaning towards the last option, but I'm still torn/confused about the whole thing...
I want to retrieve private (implementation and other) methods of a class which implements an interface and also is derived from (inherits) a base class.
How can I achieve this using reflection? Is there anyother way to achieve this?
This is wat m tryin to do. I need to view these private methods and their contents, I don't want to invoke them.
Dim assembly As System.Reflection.Assembly Dim assemblyName As String assemblyName = System.IO.Path.GetFullPath("xyz.dll") assembly = System.Reflection.Assembly.LoadFile(assemblyName) assembly.GetType("myClass").Getmethods(Bindings.NonPublic) assembly.GetType("myClass").GetMethods(BindingFlags.NonPublic) isn't working
I am playing with Asp.net MVC 3, I was wondering how do you acheive a collection rendering in the view when the collection is made of 'real world' objects. Let's say I have a collection of client, each client may have an address and an adress may have a country.
When I write the following code it crashs if one of the client has a null address (or a null country). Object reference not set to an instance of an object.
I am part of a team that is developing a SharePoint web part. My task is to create a user control which will ultimately be wrapped in another class for presentation in a web part. Because of these requirements, I must fit all of my code in a single user control.To organize my code in the code-behind, I created a few private classes for the different objects which are represented in the database. I want to add some exception handling whereby if some sort of DB exception is thrown I can update a message on the page informing the user of the problem.
My problem is that the page-level controls are inaccessible from the private class where I'm issuing the query, so even if I catch the exception I have no way of directly accessing a Label control to populate the error. I tried to create a baseclass with an EventHandler defined, but when I throw events from the private class I'm not able to catch them for whatever reason. I'm far from an OOP expert Here is a snippet: ASP Code: using System; using System.Collections; [code]....
im developing a silverlight project using silverlight 3, vs2008 and linq2sql. when projects starts, im storing all the data from database into some static list variables. so when ever i need data, im reading it from those static list variables. all i want to know is, is it good to store data in static list variables and use it when ever necessary or is it good to get data directly from DataClassesDataContext object like db.mytable. which is the rite and fastest way or retrieving data. i mean which will use less connections to database?
Suppose we declare and define the variable in one class let say FirstClass and we want to use that variable in another class let say SecondClass which is outside of FirstClass .how to do this?
I've noticed that once I've instantiated 3-4 objects now, my ASPX page is running slower. The response from the server (which is my own PC) is taking longer.
With one or two objects, the performance is same. After I instantiate 3, it slows a little, and 4 just completely wears it down.
I've read this article: [URL]
that says to avoid using session variables especially storing objects into them. Well thats exactly what I'm doing. My object has about 10 methods(~30 lines of code each) and 20 fields.
My question is, if I want to persist object in memory for each user session, how else could I store them on each postback if not in the session variable>? I can't use application variable because thats shared and not thread safe.
Google usually solves my problems for me, but this one has me stumped. I have a page with the following code, in which lstPayments is a listview control:
As you can see, I'm trying to get an alert box displayed after a new payment is entered. As I expect, lstPayments_ItemInserted is executed first, and paymentWarning is duly set to true. However, when Page_PreRender subsequently executes, paymentWarning has been re-initialised: it's false again!
The only way I can get the class-level variable paymentWarning to retain it's value between the two event handlers is to declare it static, which I don't want to do for obvious reasons. There must be something I am failing to understand about how class-level variables work in aspx pages.
I have a public shared function and I'm trying to access the values of a text box and a session variable.
I'm getting the 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."
Is there any way I can get to the values in the textboxes or session variables from within the method?
I've created a nice menu class and used it in my MasterPage like "using My.GeneralRoutines".This class is working well and everything is fine UNTIL I want to access this same instance of that class that was created at MasterPage level on "a_page.aspx.cs" (this page is using the MasterPage like :)
I would like to know how to relate my shared class to my web User controls?? For example say I add a new class my project to run a game. How do I get infomation I need from my web controls to be used in my class.Say my user select easy for the difficult mode on a radio control. I want the class to be able to see that the user control has been set to easy or have the class modify values for my web controls
I'm having a hard time understanding why the following code doesn't work. I'm sure it's something remedial that I'm missing or not understanding. I currently have a page that asks for user input. If, based on the input and logged in user, I find data from this page already in the database, I need to update the existing records rather than creating new ones, so I set a class-level bool to true. The problem is, when MyNextButton is clicked, PreviouslySubmitted is still false. So, I'm not sure how to make the value of this variable persist.
public partial class MyForm : System.Web.UI.Page { private bool PreviouslySubmitted; protected void Page_Load(object sender, EventArgs e) { MyButton.Click += (o, i) => { q = from a in db.TableA where (a.SomeField == SomeValue) select a; if(q.Any()) { PreviouslySubmitted = true; //populate the form's fields with values from database for user to revise } } MyNextButton.Click += (o, i) => { //the value of PreviouslySubmitted is false at this point, //even if I made sure it was set to true the previous postback if(PreviouslySubmitted) { //update database } else { //insert into database } }
I have custom class level validation attribute, inheriting from ValidationAttribute, on my model.
How come it doesn't register a key in the ModelState when its IsValid is false? I can see the the error message in the ModelState.Values collection, but the ModelState.Keys collection only shows an empty string "". Can I provide a key for it - presumably this is because its not assigned to a property?
I wanna be able to use ModelState.Remove in my controller to remove this error upon a certain condition, but I have no Key!
I'm getting started with Astoria/ADO.NET Data Services/WCF Data Services. Looking through a lot of the code samples out there, it appears that the MimeType attribute used to be a method level attribute. After installing the latest update, it is now a class level attribute.
If I have more than one Service Operation that I want to return as a certain MimeType, then it appears now that I have to create a new service for each operation. Is this correct?
Most examples are like this:
[WebGet] [SingleResult] [MimeType("application/pdf")] public IQueryable<byte[]> FooPDF() { var result = from p in this.CurrentDataSource.MyPDFs where p.FooID == 2 select p; return result.Take(1).Select(p => p.PDF); }
I get "Attribute 'MimeType' is not valid on this declaration type. It is only valid on 'class' declarations." when I compile, because now I can't do this.
Now, I have to do this:
[MimeType("FooPDF", "application/pdf")] public class FooService : DataService<FooDBEntities> { public static void InitializeService(DataServiceConfiguration config) { config.SetServiceOperationAccessRule("FooPDF", ServiceOperationRights.All); } [WebGet] [SingleResult] public IQueryable<byte[]> FooPDF() { var result = from p in this.CurrentDataSource.MyPDFs where p.FooID == 2 select p; return result.Take(1).Select(p => p.PDF); } }
What's worse is that I can't add duplicate MimeType attributes to my class.
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(); }
