Show option group in Angular with select and align group items properly. There is nothing special to Angular if you already know the ngFor loop. You are just missing the HTML part `optgroup`. We are going to see some working examples by using JSON data to show, you can use any service or data from anywhere. First we will see some pure HTML examples with hard coded values so we can understand... By Ali Adravi On 04 Apr 2019 Viewed: 4,357
Catch every error in applicatoin and log either to a file or in database is a good idiea. But how to catch every error in application and show a proper error page or page not found page? We will try to see how easily we can acheive it and how to log error in a file by using the microsoft provided logger feature to log error in a text (.txt) file. If you will open the startup.cs file in any... By Ali Adravi On 30 Jan 2019 Viewed: 1,886
I am going to demonstrate the use of a very popular mocking framework, Moq, to mock database calls. The example in the article is an Order Processing class, mimicking the order processing system. For the sake of simplicity, I am focusing on fetching an order from database (by order Id), adding 10% GST on the amount and then saving it back to database. public class OrderProcessing ... By Chinmay C Dey On 28 Nov 2018 Viewed: 833
Security is the main feature of any application, we will use in this article Web API 2 bearer token, created through Owin oAuth, which we created in our previous article. Pass Bearer token with every HttpRequest with the help of HttpInterceptor. In this article we will see only the authentication and guard the pages. We will implement refresh token in next article because might be you are here... By Ali Adravi On 14 Oct 2018 Viewed: 3,809
Token base authentication expires over a fixed time, to overcome on it we need to use the refresh token. We will try to create the token as well as the refresh token after successful login, refresh token will be used to generate a new token if current token is already expired and it is not too late. If you are at this page after reading many online articles on how to implement Owin, OAuth,... By Ali Adravi On 08 Oct 2018 Viewed: 5,889
Create Token with user credential & roles and authorize action methods based on role in Web API is the topic we will cover in this article. We would need to pass token in every request and decorate action methods with [Authorize(Roles = "Admin, Manager") etc. that's only the code we will need to complete our role based authentication. Check my previous article [OAuth Web API token based... By Ali Adravi On 04 Oct 2018 Viewed: 2,910
Angular 4.3.1 introduced HttpInterceptor, we will use HttpClient and new HttpInterceptor feature to handle error globally for entire application. When calling the service method, we might get some kind of server error. It can be any kind, like poor network connection to reach to the server, method itself through error due to any logical error, or unable to connect to the database, in that... By Ali Adravi On 10 Aug 2018 Viewed: 12,241
Lazy loading in angular is introduced to load the source and pages on demand. Concept is to group the feature in modules and when user load any page from that module, load the complete module only then rather than to load everything on application start. Let's try to understand the concept with example: Say we have a website which have users, customers, products etc. For lazy Loading, we will... By Ali Adravi On 30 Jul 2018 Viewed: 3,339
React WebPack and TypeScript environment setup is the first step to learn react, it is easy but seems too much settings. In this article we will see how can we do it without knowing anything about React, Webpack and typescript, rest of the things we can learn latter, once we will have environment setup. We will do it by using Visual Studio Code. Create a folder where you want to keep the... By Alicia Gonzalez On 24 Jul 2018 Viewed: 412
Validation of Entity with Entity Framework is a tricky way, but it is really simple. In this article we will try to understand how easily we can add the validation with any entity created by Entity Framework with database first approach by using partial classes and pure DataAnnotation. We will not use any if.. else... or switch... case statement to validate different property. It will work with... By Ali Adravi On 08 Jul 2018 Viewed: 889
Singleton is a design pattern in which we allow a class to be instantiated only once and use again and again from entire application. In this article we will try to see different ways to create and Singleton class and pros & cons of all the ways, we will also write some code to test it, so we can understand what's going on **1. Singleton - Not Thread Safe **: Let's write the very basic... By Ali Adravi On 03 Jul 2018 Viewed: 1,766
MVC Search Sort and Paging is common feature we need to use, so let's write the HTML Paging Helper for our project, which will work faster than anyother build-in costum grid system because they contain many other features we don't need for our application and don't support many features we want. In this article we will try to create custom HTML paging helper which will work with paging, sorting... By Ali Adravi On 07 May 2018 Viewed: 2,732
Angular animation document give some very good example to add the animation in component but it looks messy. What if we want to keep all the animation in separate file and use wherever we want. Keeping all animation in a separate file will be good idea because it will be easy to maintain and reuse the same animation as many times as we want. In this article we will create some basic animation... By Ali Adravi On 27 Mar 2018 Viewed: 2,360
Constructor is a special method, having the same name as the class/struct. When an object of class or struct is created, its constructor is called, and they usually used to initialize the data members of the new object. There are different types of constructors which we will see in detail in this article, like, default constructor, parameterized constructor, copy constructor, static constructor... By Ali Adravi On 14 Feb 2018 Viewed: 1,614
Angular email validation can be done in many different ways, by using the built-in directive, by using patterns or by creating custom directive. In this article we will try to see all the three different ways with working code in plunker. We will use our previous example and add three email text boxes to validate 1. by built-in directive, 2. by using pattern and finally we will write our own... By Ali Adravi On 23 Jan 2018 Viewed: 14,285
Angular make form validation easier than ever, we are going to check with Angular FormBuilder, FormGroup and validation together in this article, We will also see how to validate email without writing any custom directive or any other code because it is already there. Some tricky way to show and hide the error on page load and on save. We will use plunker for example: First we need to update... By Ali Adravi On 23 Jan 2018 Viewed: 2,991
Angularjs jquery calendar with minimum code to attach datepicker, how to extend to restrict the dates from a particular day, month or year, how to make calendar to validate start and end date from one control to other after user selection, how to format date before rendering or how to disable datepicker with the help of angular ngDisabled properties are some of the common points we are going to... By Ali Adravi On 26 Dec 2017 Viewed: 2,519
Angularjs 1.5 introduced component which can be used for reuseable component similar to user control in ASP.Net. We will create a component and see how we can use with different pages by just adding a single element. If we will try to creat the same as a directive then will be complicated but with component it will be very easy. **Advantages of Components**: - simpler configuration than... By Ali Adravi On 23 Oct 2017 Viewed: 1,838
Checkbox list at least one is required, checkbox list minimum 3 is required, gender at least one is required are the basic requirement for any situation. We will use the toggle trick to add remove the selected items from the list of checkbox values. In this article we are going to see the examples: 1- Radiobutton list, at least one value is required 2- Checkbox list, at least one value... By Ali Adravi On 22 Oct 2017 Viewed: 5,569
Multiple submit button in ASP.Net MVC is the common and mostly asked question in interview. In this article we will try to see different ways to use the Multiple submit button in a form and what is the best way to use multiple submit button. What we are going to try: 1. HTML5 FormAction and FormMethod attribute in submit buttons 2. Multiple Submit Buttons With Action Selector Attribute 3.... By Ali Adravi On 08 Oct 2017 Viewed: 3,411