List of Posts under C#

Following are my top 6 interview questions on the "init" accessor introduced recently in C# 9. The answers have all been fully explained through code examples. All the examples have been kept as short as possible.

Simplest explanation of AJAX based Edit, Update, Cancel operations on a row of an HTML table. An ASP.NET Core POST handler receives the updated values that can be processed for an update to a database.

In brief: Just two additions are required to implement AJAX based authorization in your existing ASP.NET Core application - first is on the javascript side - where the response code should be tested, and second on the server side where User.IsInRole has to be tested. The concept is explained in the text that follows, and a working example is described in the appended youtube video!

THE CRUX: record types are meant for storing read-only, init-once data. They serve the purpose of ValueTypes, but in reality they are reference types; they have best of both the worlds. They, being reference types, can be efficiently passed as function arguments(like class objects), and yet they carry data like structs [though read-only] but the data doesn't get copied during function calls - this promotes efficiency. They are 2-in-1: they are RefTypes but they perform the task of ValueTypes (though read-only, init-once). So with C# 9.0 we have a triad - class, struct and record. Two different instances of records are equal if they contain the same data (like structs, and un-like the classes!) The "positional record" syntax makes it easier to create their objects, and the newly introduced "with" expressions make it even easier to create their exact copies, possibly with just-in-time alterations to some of their properties.

This project is about creating an Admin Panel that would be suitable for a reporting project or an EBook that shows a table of links on the left and the corresponding content on the right side. The content is obtained by an Ajax call to an ASP.NET Core application. Source code for all the three files has been given and explained below.

In nutshell: The selection change event of the master dropdown is used to send the "id" of the selected item to the server, which sends back a collection of items for the slave dropdown. A javascript based Ajax GET request is used for this communication with the server.

The following project has a textbox with a send button. The click event fires an AJAX GET request and sends a string parameter to an ASP.NET Core application, which responds by converting the parameter to its uppercase equivalent. The client side script has been written using pure javascript.

How to POST an ASP.NET Core Razor FORM through an Ajax Request. We discuss a practical approach that is to-the-point and easy to understand. The given code is ready to copy-paste!

Some, not all, routes need a daily downtime between 17 hrs to 18 hrs. So they have to be shut during that period so that no requests are processed. Any request has to be redirected to another page or a website, say, hoven.in. How should that be implemented?

Write an ASP.NET Core application such that the route "/home/index/N", where N is any int number, executes only if the website is hosted on port 67291 of "hoven.in" or "www.hoven.in". It should return 404 even if it is hosted on any subdomain like "*.hoven.in:67291"?

This is a summary of the concepts of routing and route templates in asp.net core. We have taken a practical exercise to develop the concepts in an interesting way.

Use the concepts learnt till now, and without using razor, and without mvc framework, create a contact form that has a text box (cusName) and a date picker (meetOn), and that posts data to your asp.net core application. The application echoes this data back to the browser.

This tutorial explains everything necessary to get you started with the middleware in ASPNET Core. We explain the built-in middleware components as well as the Use, Map and Run extension methods through practical code.

This tutorial explains the Startup class in ASP.NET, along with the methods of this class. We also explain how a custom middleware can be attached by IStartupFilter.