Saturday, February 25, 2017

Visual C# Technical Guru - January 2017

Another month as a judge in Microsoft TechNet Guru Awards under Visual C# category. The TechNet Guru Awards celebrate the technical articles on Microsoft TechNet.

Post in WikiNinjas Official Blog,
Visual C# Technical Guru - January 2017
Happy Coding.


Thursday, February 16, 2017

Creating a MVC ASP.NET Core Application Powered by React

Recently I have started to explore React and this morning, I saw this blog post Building Single Page Applications on ASP.NET Core with JavaScriptServices published on .NET Web Development and Tools Blog. And when I started to read this post, I got quite surprised and amazed.

Basically the summary is with the latest version of .NET Core SDK, you can use following templates to create a project using dotnet new.
dotnet new --list
While there are a lot of information about all of this in above mentioned post, in this post, I am going to explore the React project template. (Not React with Redux, at least not on this post). Of course, to start exploring , first you need to create it.

I have the latest .NET Core SDK and Node installed.
dotnet  and Node version
And I have installed Single Page Application (SPA) templates as per the original blog post.
Now let’s start some React time.
dotnet new react
Once the project is created, let’s see what dotnet exactly has created for us.
Project Structure
You can see that basically the structure is more or less the same to web application projects created using Visual Studio.

In addition you have webpack, babel and TypeScript configuration files (if you haven’t worked with webpack, and babel before, may be you can read this previous post of mine: Getting Started with React, Babel and Webpack). And of course there is a Dockerfile as well.

Your familiar files which bootstraps ASP.NET Core and MVC (Program.cs, Startup.cs, Controllers and Views folders etc.) are there. React components are placed inside ClientApp folder.

While all the client side dependencies are listed in package.json, server side dependencies are listed in the .csproj it self (you can find more information about the project.json to .csproj migration in this previous post of mine: Where is project.json in Default .NET Core Application Templates in Visual Studio 2017). On the server side dependencies, one of the important thing to note is, reference to “Microsoft.AspNetCore.SpaServices”.

Server Side Dependencies
If you open up Startup.cs, inside Configure method which configures the HTTP request pipeline, while the environment is Development, we are using the Webpack Dev Server along with it’s HMR (Hot Module Replacement) feature.
Use of Webpack Dev Server
This is made all possible by using “Microsoft.AspNetCore.SpaServices” package.  And that is a very handy thing when it comes to development, you don’t have to refresh the page after making client side code changes.

So now let’s run the application and see what happens. Open up a command prompt inside the project folder and run the following commands to restore/install server side and client side packages.
dotnet restore
npm install
Finally it’s the command of joy.
dotnet run
dotnet run
Let’s navigate to http://localhost:5000 from the browser.
MVC ASP.NET Core with React
Isn’t it marvelous!

Happy Coding.


Wednesday, February 1, 2017

Getting Started with React, Babel and Webpack

React is getting popular everyday and I believe you can find many articles to know what React is. In this post let’s see how we can setup a HelloWorld React application using some set of nice tools.

To build this sample, I am going to use following set of tools and libraries.
This is the editor that I am going to use, and of course, you can use any editor you prefer. But I suggest you try out Visual Studio Code as it offers great features for JavaScript developers. All these features are made possible by the new JavaScript Language Service (Code name : “Salsa”)  which is also getting shipped with Visual Studio 2017.
I am going to use npm as the JavaScript package manager.
Babel is the transpiler here. We can use all the great features in ECMAScript 6, also known as ECMAScript 2015 (ES6/ES2015) and Babel will make sure they will get transpiled to ES5 which will work on all browser versions.
Webpack is the module bundler that I am using, it will be responsible for effectively bundling the files based on the configuration I provide.
I will be using webpack-dev-server to test and host my application. It provides nice features such as hot reloading. We just need to modify the code and changes will get reflected. We don’t need to refresh the browser.

Now it’s time to write some code. I will start by installing the global dependencies that I need. I am going to install webpack-dev-server as a global npm package.
npm install webpack-dev-server -g
Now I am creating a folder for the application “HelloWorldReact” and inside there creating another folder named “app” and that’s where I am going to have all my code files.

From the “HelloWorldReact” folder, I am opening up a command prompt and running the npm init command to create the package.json file. On the prompts, I am just keeping the default values as it is.

Now let’s install the packages using npm.

npm install react react-dom --save
npm install webpack babel-core babel-loader file-loader react-hot-loader babel-preset-es2015 babel-preset-react --save-dev
As you already know upon the installation, package.json will get updated. I am further modifying the package.json as follows adding a script.
  "name": "helloworldreact",
  "version": "1.0.0",
  "description": "",
  "scripts": {
    "start-webpack-server": "webpack-dev-server --hot --inline --colors --progress"
  "author": "",
  "license": "ISC",
  "dependencies": {
    "react": "^15.4.2",
    "react-dom": "^15.4.2"
  "devDependencies": {
    "babel-core": "^6.22.1",
    "babel-loader": "^6.2.10",
    "babel-preset-es2015": "^6.22.0",
    "babel-preset-react": "^6.22.0",
    "file-loader": "^0.9.0",
    "react-hot-loader": "^1.3.1",
    "webpack": "^1.14.0"
Here, the packages listed under dependencies are only needed when running the application in production. The packages listed under both dependencies and devDependencies are need when developing the application. Under devDependencies, I have installed,
  • Core Babel package
  • Babel loader for Webpack
  • Two presets to make sure ES6/ES2015 and react transpilation
  • File loader for Webpack
  • Webpack & react-hot-loader to enable webpack dev servers hot loading for React (webpack-dev-server should be running with --hot flag).
The script is for running webpack-dev-server with some set of flags. To know about what these flags are visit webpack-dev-server CLI.

Now let’s create a js file to configure webpack. I am naming it as webpack.config.js.

var path = require('path');
var webpack = require('webpack');
module.exports = {
  context: path.join(__dirname, 'app'),
  entry: {
    javascript: './app.js',
    html: './index.html'
  output: {
    path: path.join(__dirname, 'dist'),
    filename: 'bundle.js'
  devServer: {
    inline: true,
    port: 9999
  module: {
    loaders: [
        test: /.js?$/,
        loader: 'babel-loader',
        exclude: /node_modules/,
        query: {
          presets: ['es2015', 'react']
        test: /\.html$/,
        loader: "file?name=[name].[ext]",
Here I have specified the entry files, bundle output directory, devServer information and loaders. And for js files, I have set the loader as Babel. So what happens in the js loader here is when you come across a path that resolves to a '.js' inside of a require()/import statement, use the babel-loader to transform it before you add it to the bundle. For more information about webpack loaders, go to

Now let’s create the entry files. Navigate to the “app” folder, and let’s create a app.js and index.html files.

import React from 'react';
import ReactDOM from 'react-dom';
class App extends React.Component {
  render() {
    return (
        <h1>Hello World</h1>
ReactDOM.render(<App />, document.getElementById('main'))
<!DOCTYPE html>
<html lang="en">
  <meta charset="UTF-8">
  <title>Hello World</title>
  <div id="main">
  <script src="/bundle.js"></script>

Now I am almost good. From the command prompt run the following command.
npm run start-webpack-server 
Now you should be able to see that bundling is happening and webpack dev server is starting. Once completed, navigate to http://localhost:9999 and if all is good you should see something like below.

Now try changing the text inside our React component and just save the file, you should be able to see the changes in the browser without refreshing the browser.

Still the bundled files are not outputted to the destination (HelloWorldReact/dist). When you are ready for the deployment, from the command prompt, you can run webpack -d command to output files.

I have made the code available on GitHub. Feel free to fork.

Happy Coding.