Configuration Error Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately. Parser Error Message: Cannot create an abstract class.
Source Error:
Line 150: <providers>
Line 151: <clear/>
Line 152: <add name="NDMSMembershipProvider"
type="CSW.Web.Security.NDMSMemberProvider"/>
Line 153: </providers>
Line 154: </membership>
Why do we use the reference of abstract class (or base class) to create object of it's sub-class. eg: TextWriter is the abstract class for StreamWriter & StreamWriter.
From the following URL i got some doubts about the Recommendations for using Abstract class vs interfaces
[URL]
1. If you anticipate creating multiple versions of your component, create an abstract class. Abstract classes provide a simple and easy way to version your components. By updating the base class, all inheriting classes are automatically updated with the change. Interfaces, on the other hand, cannot be changed once created. If a new version of an interface is required, you must create a whole new interface. { Is there any example for this t ounderstand throughly ?} If you are designing small, concise bits of functionality, use interfaces. If you are designing large functional units, use an abstract class. If you want to provide common, implemented functionality among all implementations of your component, use an abstract class. Abstract classes allow you to partially implement your class, whereas interfaces contain no implementation for any members. { Is there any example for this t ounderstand throughly?
I just want to know that how can I utilize the concept of Abstract class, virtual class etc. in my shopping cart website. I have read the tutorial out there on internet and I saw some examples too, but those examples are so general that they dosen't fit into real world scenerio like I am searching for a shopping website. Same questions again and again comes to my mind that why to made a class only to give the declaration of methods and property.
I know what Singleton Pattern means and Abstract class means.What I wanted to know was how would this apply to real world.Could anyone give me any good example or simple explanation.Say I have a simple website, why would I use any of the above if any.Why would it simplify my architechture.
I am developing a couple of small ASP.NET application and would like to know what pattern. approach do you use in your projects.
My projects involve databases, using Data access and Business logic layers.
The data-access approach that I was using so far is the following(I read in some book and liked it):
For DAL layer:
Creating an abstract class that will define all database manipulation methods to implement. The abstract class will contain a static "Instance" property, that will load (if instance == null) an instance (Activator.CreateInstance) of the needed type (a class that implements it).
Creating a classes that implement this abstract class, the implementation will be according to the databases (SQL, mySQL and etc) in use.
With this I can create different implementation according to database in use.
For BLL layer:
A class that encapsulates all all retrieved fields , and static methods that will call the DAL classes.
I am attempting to bind a Repeater (but it could be a GridView or ListView) to a list of objects. The List's type is an abstract type, which has two different classes derived from it, both with different properties. Because they have different properties, I cannot just have one ItemTemplate. If I bind a control to a property of one type of class and the other type doesn't have it, it throws an error.
Here's where I'm at:
I cannot use <% if (whatever) { %> some stuff <% } else { %> some other stuff <% } %> because I cannot access the databound item to make the choice based on its type. I cannot use the <%# %> syntax, which lets me use the databound information, because you cannot code logic like if...then...else. I cannot (rather not) call a function and return a string with the code because what I want to render is complex and contains further nested databound controls. Has anyone found an ingenious way of doing if it is this type of object, display these controls, else display these other controls?
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).
I have a table which houses two entities. StaticProgram and DynamicProgram. There is one column in that table called ProgramType which determines if a program is of Type static or Dynamic. Though these two entities are stored in one table (I am guessing because the primitive fields for Static and Dynamic programs are exactly the same) but from a business point of view these are two VERY different entities.
So, I created two Classes StaticProgram and DynamicProgram. However, I donot want to create two seperate Data Access Classes because it is going to be the exact same code replicated twice. I tried creating a "Program" class as base class and inherited StaticProgram and DynamicProgram classes but down casting is not supported so I can't return a "Program" object from the data access class and cast it to "StaticProgram" class.So, what are my options? Can I create an IProgram interface and have StaticProgram and DynamicProgram implement that interface and have my Data Access class return IProgram?
I'm building a web app that will keep a events in a database and add the event to a Google calendar on insertion.
I have three types of events, PendingEvents, ApprovedEvents, and DeniedEvents. I'm using single table inheritance through LINQ-to-SQL, with the Event class being abstract and the 3 types inheriting from it
Each type of Event is stored in calendars differently. I would like to use an abstract member function in Event called AddToCalendar.
I'm trying to set this up in a separate class file because I'm using the LINQ-to-SQL designer and I don't want these to be overwritten if I change the LINQ diagram.
However, I get an error from all three inherited classes that "'WebCal.ApprovedEvents' does not implement inherited abstract member 'Edu.Northwestern.WebCal.Event.AddEventToCalendar()' WebCalendarWebApplication1App_CodeWebCalDataSource.designer.cs"
It looks like it won't check my outside file and only looks at the designer.
The non-designer partial class file looks something like this:
public partial class WebCalDataSourceDataContext : System.Data.Linq.DataContext {
i have the below code i want to put in a global method set as static so that i can build a couple tree views on my asp.net web app. now i have each building its own tree view using the code below. i was thinking to make a global static method to generate the node structure such as this and then just assign them to the tree view in my pages... or something like this. i dotn care about the details of the actual solution as long as i can have a single method to call like "buildTree()" that will be able to be used to bind the tree view controls to.toughs?
DataTable dtProjects = new DataTable(); DataTable dtRelease = new DataTable(); using (SqlConnection con = Global.GetConnection())
All I want to do is learn how to create a class procedure. And then. How to call it. As an example, A + B = C is the procedure. I would create a class. Right? Then do I name the procedure and put it in the class? Or create a new class for each procedure? Then I would want to, on a local level, substitue values for A & B to return C. So, if the public procedure exists, how to I call it? I know that this is really simple stuff, but I need examples to be simple.
I am trying to create a pageBase class where I can dynamically pull data from the database and display it on a web page. Each page I specifically set an ID for the sql query which pulls back the information such as page title and page text.
my problem is that I can't seem to pass the information captured from the query to the page. I get problems such as can't convert string type to literal and I need to declare a new keyword to an object.
A instance of a class is created in the partial class of an aspx page.Under page_load or button click method I'm trying to set the value to the class. but when each postback takes place new instance is created and I'm losing the previous value.
public partial class DatabaseSelection : System.Web.UI.Page { DBProperties dbpro; Metadata obmeta; protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { dbpro = new DBProperties(); }
Yet when I try to create an object of this control type in a class (in my app_code folder) it doesn't allow me.
Controls_MyUserControl dummy = new Controls_MyUserControl();
The potentially strange thing is when I put this code into a code behind of a page, it works.
what I need to do to have the usercontrol to be able to be created in my class in the app_code folder?
My guess is, is that I need to reference the control in a "using" statement at the top, but I'm not sure what that'd be.
It's not in a namespace to my knowledge (at least there's no namespace, in the code behind of the actually user controls). Though I'm not sure if it inherits one from the System.Web.UI.UserControl.
I am using vs 2010, mvc, linq to sqlMy Model is .dbmliletbl_teacher,tbl_class,tbl_subject etc are involvedI write code in my controller for table join.