Category: .NET

.NET (dotnet) is a developer platform made up of tools, programming languages, and libraries for building many different types of applications.

So, there are various implementations of .NET (dotnet). Each implementation allows .NET code to execute in different places—Linux, macOS, Windows, iOS, Android, and many more. This framework has two main versions:

  1. Framework is the original implementation of .NET. It supports running websites, services, desktop apps, and more on Windows.
  2. Core is a cross-platform implementation for running websites, services, and console apps on Windows, Linux, and macOS. .NET Core is open source on GitHub.

Then, Xamarin/Mono is a .NET (dotnet) implementation for running apps on all the major mobile operating systems, including iOS and Android.

The .NET Standard is a formal specification of the APIs that are common across .NET implementations. This allows the same code and libraries to run on different implementations.

Therefore, the two major components of .NET (dotnet) Framework are the Common Language Runtime and the .NET Framework Class Library.

  • The Common Language Runtime (CLR) is the execution engine that handles running applications. It provides services like thread management, garbage collection, type-safety, exception handling, and more.
  • The Class Library provides a set of APIs and types for common functionality. It provides types for strings, dates, numbers, etc. The Class Library includes APIs for reading and writing files, connecting to databases, drawing, and more.

Summarize, .NET (dotnet) applications are written in the C#, F#, or Visual Basic programming language. Code is compiled into a language-agnostic Common Intermediate Language (CIL). Compiled code is stored in assemblies—files with a .dll or .exe file extension.

At the end, when an app runs, the CLR takes the assembly and uses a just-in-time compiler (JIT) to turn it into machine code that can execute on the specific architecture of the computer it is running on.

Android.Content.Res.Resources+NotFoundException: Resource ID #0x0

Enrico

I’ve just created a simple MasterDetailPage and in the code I inserted an icon for the left page with: public MainPage() { InitializeComponent(); BackgroundColor = Color.FromHex("#007acc"); Icon = "settings.png"; } I tried to deploy my app on an Android emulator but I can’t deploy it because Android.Content.Res.Resources+NotFoundException: Resource ID #0x0. I checked everthing and evething seemed fine. The problem is the icon! You have to remove Icon from the code and in the XAML page type the following code: <ContentPage.Icon> <OnPlatform x:TypeArguments=”FileImageSource”> <OnPlatform.iOS>settings.png</OnPlatform.iOS> </OnPlatform> </ContentPage.Icon> Happy coding!

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Visual Studio updates Xamarin

Enrico

When you open Visual Studio 2015 and there is a pop windows to invite you to click on it for updating Xamarin and you click, nothing happends. There is a bug but clicking the update available popup was fixed in one of the recent releases. You can manually update in the Options menu under Tools. As for the errors, I get those all the time. Support packages can often be a problem. Update to the latest XF package. Try deleting bin, obj, and the contents of packages folders and rebuild.

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Start Edge Animate when is in the screen

Enrico

I’ve come across a few sites that will tie window scrolling with animation. When used in a subtle, small fashion, this is kind of cool. When used to change large portions of the view or really screw with scrolling, I detect it. Like most things, it all comes down to how you use it I suppose. But I was thinking recently – how can we do this with Edge Animate? Change edgePreload.js In a file calles something_edgePreload.js you find a line similar to the follow: if (AdobeEdge.bootstrapLoading) { signaledLoading =…

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How to update the data in listview in Xamarin.Forms?

Enrico

First you add a new class as a ViewModel like: public class RoomViewModel : BaseViewModel { [here following code] } If you don’t have BaseViewModel try to download from nuget Refractored.MvvmHelpers. Then in your class define an observable collection like public ObservableCollection<RoomRecommandation> _roomSuggestionList = new ObservableCollection<RoomRecommandation>(); public ObservableCollection<RoomRecommandation> Recommendations { get { return _roomSuggestionList; } } In your ContentPage add a listview like: <ListView ItemsSource="{Binding Recommendations}"> <ListView.ItemTemplate> <DataTemplate> <ViewCell> <Grid Padding="10" RowSpacing="10" ColumnSpacing="10"> <Grid.RowDefinitions> <RowDefinition Height="" /> </Grid.RowDefinitions> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" /> <ColumnDefinition Width="" /> <ColumnDefinition Width="Auto" /> </Grid.ColumnDefinitions> <controls:CircleImage…

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Xamarin Forms MasterDetail Page Navigation Recipe

Enrico

In this recipe I will show you how to add a hamburger menu to your Xamarin Forms application using the MasterDetailPage class. The Xamarin.Forms MasterDetail Page consists of one page for the master and one or more pages for the detail. When used for the main navigation, as in this recipe, we will have a single master page and 4 detail pages. The code for this recipe comes from the Xamarin Forms CRM sample. I have simplified and streamlined the code, and a full Xamarin Studio solution is included at…

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Xamarin Studio: complete uninstall on Mac

Enrico

Remove these directories: /Applications/Xamarin Studio.app /Developer/MonoTouch /Developer/MonoAndroid /Library/Frameworks/Mono.framework /Library/Frameworks/Xamarin.Mac.framework /Library/Frameworks/Xamarin.Android.framework Locations in your user directory: ~/Library/Caches/Xamarin ~/Library/Caches/XamarinStudio-4.0 ~/Library/Developer/Xamarin ~/Library/Developer/XamarinStudio ~/Library/Logs/Xamarin ~/Library/Logs/XamarinStudio-4.0 ~/Library/Preferences/Xamarin ~/Library/Preferences/XamarinStudio-4.0 ~/Library/Xamarin ~/Library/Xamarin.Mac ~/Library/MonoTouch ~/Library/MonoAndroid ~/Library/XamarinStudio-4.0 That’s all there is afaik.

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ASP.NET LinkButton: children disappears after postback

Enrico

I have a LinkButton with image and label inside it or tags i and span as in the following picture. The code in the page is: <asp:LinkButton ID="LinkButton1" runat="server"> <i class="glyphicon glyphicon-plus"></i> <span class="js-add-button" runat="server" id="Span1">Add New</span> </asp:LinkButton> After a postback everything inside the LinkButton disappeared. I’ve spent two days to understand why and the solution is very easy. <asp:LinkButton ID="LinkButton1" runat="server"> <i class="glyphicon glyphicon-plus" runat="server"></i> <span class="js-add-button" runat="server" id="Span1">Add New</span> </asp:LinkButton> The tag i doesn’t have runat="server" and for that you lost all content inside the LinkButton. Happy coding!

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Remove multiple line in the same file with C#

Enrico

Read the file, remove the multiple line (but it saves one of them) in memory and put the contents back to the file (overwriting) and create a backup file with the original file.   using System; using System.Collections.Generic; using System.IO; using System.Linq; namespace DelMultiLine { class Program { static void Main(string[] args) { if (args.Count() == 0 || args.Count() > 2) { Console.WriteLine(“\nDelMultiLine (by Enrico Rossini – puresourcecode.com)”); Console.WriteLine(“———————————————————————–“); Console.WriteLine(“Remove duplicate line in a file\n”); Console.WriteLine(“Usage:”); Console.WriteLine(” delmultiline <Filename> <resultFilename>\n”); Console.WriteLine(“filename: define a full path for the file you want…

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Dijkstra’s Algorithm in C# with Generics

Enrico

I recently needed to to implement a shortest-path algorithm (to identify preferred domain controllers using site link costs) and I found Dijkstra’s Algorithm Path class using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace DijkstraAlgorithm { public class Path<T> { public T Source { get; set; } public T Destination { get; set; } /// <summary> /// Cost of using this path from Source to Destination /// </summary> /// /// Lower costs are preferable to higher costs /// </remarks> public int Cost { get; set; } } }…

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DistinctBy in Linq (Find Distinct object by Property)

Enrico

public class Size { public string Name { get; set; } public int Height { get; set; } public int Width { get; set; } } Consider that we have Size Class for advertisement which is having Heigth, Width and Name as property in it. Now Requirement is I have to find out the all product with distinct Name values. Size[] adv = { new Size { Name = “Leaderboard”, Height = 90, Width = 728 }, new Size { Name = “Large Rectangle”, Height = 280, Width = 336…

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Data and data access technologies

Enrico

In my previous post I spoke about key layers of distributed applications. Now we will go through the most crucial layer of any distributed application, the data layer. In this part, you will be introduced to various database technologies, along with .NET-related technologies. Data can be stored in a wide range of data sources such as relational databases, files on the local filesystems, on the distributed filesystems, in a caching system, in storage located on the cloud, and in memory. Relational databases (SQL server): This is the traditional data source…

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Key layers of distributed applications

Enrico

Every application that is going to be used by end users should be designed appropriately as users are expecting to process information from various data sources that might be geographically distributed. They are also expecting this information to be up-to-date and capable of being inflected very fast. Designing such applications is not an easy task and involves integration among different groups of components. Let’s review the layers that form a typical distributed application. The responsibilities in a distributed system can be divided into four layers: The data layer The business…

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C# and HTML5: drag and Drop elements

Enrico

HTML5 API includes Drag and Drop (DnD) native functionality. The event listener methods for all the drag and drop events accept Event object which has a readonly attribute called dataTransfer. The event.dataTransfer returns DataTransfer object associated with the event This is the list of events fired during the different stages: Event Description dragstart Fires when the user starts dragging of the object. dragenter Fired when the mouse is first moved over the target element while a drag is occuring. A listener for this event should indicate whether a drop is…

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World’s First Autonomous Drone, The DJI Phantom 4, Revealed

Enrico

Recently, the Irish Internet of Things chip maker Movidius, has won a multi-million dollar deal with Google, and it has been revealed as the brain behind the breakthrough autonomous drone, the DJI Phantom 4. This autonomous drone, which went on sale in Apple Stores across the US last week, features a new visual guidance facet, which sticks to and follows a subject, and can stay in a fixed position without the need of a GPS signal. Described as the first in the industry, the addition of Movidius chips technology and…

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Integration with C# and ReactJS

Enrico

The goal for this project is to show a list of books with ReactJS from a WebAPI written in C#. You can download this project from Github. New project Start by creating a new ASP.NET MVC 4 project: 1. File → New → Project 2. Select ".NET Framework 4" and Templates → Visual C# → Web → ASP.NET MVC 4 Web Application. Call it "CSReact" 3. In the "New ASP.NET MVC 5 (or 4) Project" dialog, select the MVC (or empty) template. Install ReactJS.NET We need to install ReactJS.NET to…

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ReactJS: component Lifecycle and Rendering

Enrico

These are the functions that will be, or can be, included in your specification object when you’re creating a component. Part of these specification functions are lifecycle functions, which when encountered, will show the details as to when they execute during the life of a component. Function invocation order during the initial render of a React component Component lifecycle that happens when the state changes on a component Lifecycle of a component when it has altered props render Every React component must have a render function. This render function will…

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How to check if IsNumeric?

Enrico

If you need to check if something is a number, in C# doesn’t exist a function for that. That I’ve created the following code. public bool IsNumeric(object Expression) { if (Expression == null || Expression is DateTime) return false; if (Expression is Int16 || Expression is Int32 || Expression is Int64 || Expression is Decimal || Expression is Single || Expression is Double || Expression is Boolean) return true; try { if (Expression is string) Double.Parse(Expression as string); else Double.Parse(Expression.ToString()); return true; } catch { } // just dismiss errors…

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Customize Json result in Web API

Enrico

If you work with Visual Studio 2015 and WebAPI, this short post is for you! We have to make our Web API project easy to debug so, I’m going to remove the XML formatter. I’m doing that because I’m in a test project and I’d like to see the response in the browser. The easily way to force the response to Json for all Web API requests is to remove the XML. Obviously you shouldn’t do it in production. Global.asax var formatters = GlobalConfiguration.Configuration.Formatters; formatters.Remove(formatters.XmlFormatter); Now we can start change…

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Creating a URL shortener using ASP.NET WepAPI and MVC: error handling

Enrico

In the two previous post I discussed about the first step to creare this application and the implementation of the business logic. Now we can implement the error handling. We have two custom exception classes: ShorturlConflictException (when a segment already exists) and ShorturlNotFoundException (when a segment isn’t found in the database). There is also a third type: an unexpected exception, for example when there is no database connection. Normally, the user will see these errors. We have to build a mechanism where these exceptions are caught and a nice error…

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Creating a URL shortener using ASP.NET WepAPI and MVC: implementing the business layer

Enrico

In my previsious post I discussed the first implementation of this application. In this post I’m explained how to implement the business layer. First of all you make sure the Business project references the Data, Entities and Exceptions projects. In the Exceptions project you add two new classes: ShorturlConflictException using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace PSC.Shorturl.Web.Exceptions { public class ShorturlConflictException : Exception { } } ShorturlNotFoundException using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace PSC.Shorturl.Web.Exceptions { public class ShorturlNotFoundException : Exception {…

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Agile approaches

Enrico
Agile Wallpaper

There are a number of specific Agile approaches, as well as a generic agile style of working. Extreme Programming is a software development methodology, containing mainly programming practices such as Test Driven Development, Pair programming and Continuous Integration, but little management. Lean, which came from the manufacturing environment, is all about efficient processes. The focus is on eliminating waste from the production line and thereby reducing cost. Scrum is a very simple agile process, designed for delivering software in small chunks, taken from a backlog of work to be done.…

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Davos: Smart machines set to transform society

Enrico

Artificial intelligence will spur economic growth and create new wealth. Machines that “think” like humans will help solve huge problems, from curing cancer to climate change. Yet millions of human workers will need to retrain, as robots make their existing jobs redundant. These are the contrasting messages provided by the world’s leading technologists during the World Economic Forum in Davos this week, as political and business leaders ponder how best to respond to the rise of smart machines. Sebastian Thrun, the inventor of Google’s self-driving cars and an honorary professor…

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Creating a URL shortener using ASP.NET WepAPI and MVC

Enrico

In this tutorial, I use several techniques and tools. I use Microsoft Visual Studio 2015 and the latest version of all components. ASP.NET MVC: Microsoft’s modern web application framework. As the name says, it pushes you to use the MVC (model view controller) software design principle. ASP.NET Web API: Web API and MVC are used together in many applications. With MVC, the HTML of the web pages are rendered on the server, and with Web API you can, like the name says, create an API. Web API also uses the…

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